Merge seed-compat (item-table cross-validation vs C reference)

Instrumented the C game on modern-rogue with a DUMP mode (patch in
testdata/c_seedcompat.patch) that forces the RNG seed and prints the
per-seed item appearance tables — potion colors, scroll names, ring
stones, wand/staff materials — in the normal init order, before initscr
so no terminal is needed. Captured its output for four seeds as
testdata/item_tables.golden.

TestSeedCompatItemTables regenerates the same tables from the Go port
via New(Params{Seed, Wizard: true}) and checks they match the golden
byte for byte. They do, for all four seeds — proving the LCG and its
consumption order through the whole init sequence (init_probs →
init_player → init_names → init_colors → init_stones → init_materials,
including init_player's arrow rnd(8)+rnd(15)) agree with C exactly.

testdata/README.md documents how to regenerate the golden.

.golangci.yml

@@ -0,0 +1,38 @@
+version: "2"
+
+run:
+  timeout: 5m
+  modules-download-mode: readonly
+
+linters:
+  default: all
+  disable:
+    # Genuinely incompatible with project patterns
+    - exhaustruct      # Requires all struct fields
+    - depguard         # Dependency allow/block lists
+    - godot            # Requires comments to end with periods
+    - wsl              # Deprecated, replaced by wsl_v5
+    - wrapcheck        # Too verbose for internal packages
+    - varnamelen       # Short names like db, id are idiomatic Go
+    # Repo-specific exceptions approved by sneak (2026-07-06)
+    - paralleltest     # Requires t.Parallel() in every test
+    # Approved by sneak 2026-07-07
+    - testpackage      # Tests use internal package game to reach unexported state
+    - exhaustive       # C-faithful switches handle only the cases C handled
+    - mnd              # C-faithful gameplay literals; naming them hurts C-greppability
+
+linters-settings:
+  lll:
+    line-length: 88
+  funlen:
+    lines: 80
+    statements: 50
+  cyclop:
+    max-complexity: 15
+  dupl:
+    threshold: 100
+
+issues:
+  exclude-use-default: false
+  max-issues-per-linter: 0
+  max-same-issues: 0

MEMORY.md

@@ -0,0 +1,41 @@
+# Project Memory
+
+Working notes for agents on this repo. Read this alongside TODO.md (which holds
+the step queue and workflow) before starting work.
+
+## Error handling
+
+Panicking on bad/unexpected errors is allowed and preferred over threading
+unlikely error returns through game code — e.g. write-side Close/encode failures
+where continuing would mean corrupt state. The game already unwinds C's exit()
+calls via a gameEnd panic recovered in Run. Return errors where a caller
+genuinely handles them (save-file prompts, restore validation). Reserve
+deliberate `_ =` discards for true best-effort paths (scorefile writes,
+signal-time autosave), always with a comment saying why.
+
+## Linting
+
+The .golangci.yml is the house standard and may only be modified with sneak's
+explicit permission. To disable a linter, ask, explaining what the linter does;
+he approves specific exceptions, which are recorded in the config's
+"Repo-specific exceptions" block with the approval date. Approved so far:
+paralleltest (2026-07-06); testpackage, exhaustive, and mnd (2026-07-07). The
+complexity linters (cyclop, gocognit, nestif) are enabled and clean as of
+refactor step 7 (2026-07-07): the whole golangci-lint run is 0 issues, so keep
+it that way — decompose new hot spots rather than reaching for a nolint.
+Line-level //nolint with a reason is used sparingly for C-faithfulness (e.g. the
+authentic "missle" message spellings) and provably-safe gosec conversions; each
+needs a justifying comment.
+
+## Faithfulness
+
+Behavior must not change during the idiomatic-Go refactor unless a TODO step
+says so. The 80x24 seed-compatible gameplay, message text (including original
+typos), RNG call order, and C quirks (documented in tests like
+TestHoldScrollGreedyMonsterQuirk) are contract. Doc comments keep their "(file.c
+func_name)" breadcrumbs.
+
+## Debugging
+
+Write real, committed test files with t.Logf output and run plain `go test -v`;
+no throwaway scratch scripts. Successful debug probes become regression tests.

Makefile

@@ -0,0 +1,35 @@
+# Development convenience targets. This repo is exempt from the standard
+# policy scaffold (no Dockerfile, CI, or REPO_POLICIES.md); this Makefile
+# is only a thin wrapper around the Go toolchain, golangci-lint, and
+# prettier so `make fmt` / `make check` behave the same as in sneak's
+# other repos.
+
+GO_PKGS  := ./...
+MD_FILES := $(shell git ls-files '*.md')
+PRETTIER := prettier --tab-width 4 --prose-wrap always
+
+.PHONY: check fmt fmt-check lint test
+
+# Format, lint, and test — the full local pre-commit gate.
+check: fmt-check lint test
+
+# Format Go and Markdown in place.
+fmt:
+	gofmt -w .
+	$(PRETTIER) --write $(MD_FILES)
+
+# Fail if any Go or Markdown file is not formatted.
+fmt-check:
+	@unformatted="$$(gofmt -l .)"; \
+	if [ -n "$$unformatted" ]; then \
+		echo "gofmt needed on:"; echo "$$unformatted"; exit 1; \
+	fi
+	$(PRETTIER) --check $(MD_FILES)
+
+# Run the house linter (config in .golangci.yml).
+lint:
+	golangci-lint run $(GO_PKGS)
+
+# Run the test suite.
+test:
+	go test $(GO_PKGS)

README.md

@@ -2,19 +2,19 @@
 
 [![License](https://img.shields.io/badge/license-BSD-blue.svg)](LICENSE.TXT)
 
-**Rogue** is the original dungeon-crawling adventure game that spawned an
-entire genre. This branch is a faithful Go port of Rogue 5.4.4: explore
-procedurally generated dungeons, fight monsters, collect treasure, and
-attempt to retrieve the Amulet of Yendor.
+**Rogue** is the original dungeon-crawling adventure game that spawned an entire
+genre. This branch is a faithful Go port of Rogue 5.4.4: explore procedurally
+generated dungeons, fight monsters, collect treasure, and attempt to retrieve
+the Amulet of Yendor.
 
-**Original authors:** Michael Toy, Ken Arnold, and Glenn Wichman
-(1980–1983, 1985, 1999).
+**Original authors:** Michael Toy, Ken Arnold, and Glenn Wichman (1980–1983,
+1985, 1999).
 
 The port is function-by-function faithful to the classic C sources — same
-dungeon generation (seed-compatible RNG), same combat math, same item
-tables, same messages. The C reference implementation lives on the
-`master` and `modern-rogue` branches; [ARCHITECTURE.md](ARCHITECTURE.md)
-documents both the original program structure and the design of this port.
+dungeon generation (seed-compatible RNG), same combat math, same item tables,
+same messages. The C reference implementation lives on the `master` and
+`modern-rogue` branches; [ARCHITECTURE.md](ARCHITECTURE.md) documents both the
+original program structure and the design of this port.
 
 ## Building and running
 
@@ -40,13 +40,12 @@ go build ./cmd/rogue
 
 Press `?` in game for the full list.
 
-- **arrows** or **h/j/k/l/y/u/b/n** — move (shift to run, ctrl to run
-  until adjacent)
+- **arrows** or **h/j/k/l/y/u/b/n** — move (shift to run, ctrl to run until
+  adjacent)
 - **`.`** rest, **`s`** search for hidden doors and traps
 - **`i`** inventory, **`,`** pick up, **`d`** drop
 - **`q`** quaff potion, **`r`** read scroll, **`e`** eat food
-- **`w`** wield weapon, **`W`** wear armor, **`P`**/**`R`** put on /
-  remove ring
+- **`w`** wield weapon, **`W`** wear armor, **`P`**/**`R`** put on / remove ring
 - **`t`** throw, **`z`** zap a wand, **`f`**/**`F`** fight
 - **`>`**/**`<`** take the stairs
 - **`S`** save, **`Q`** quit
@@ -61,8 +60,8 @@ export ROGUEOPTS="name=YourName,terse,jump,fruit=mango"
 ROGUE_WIZARD=1 SEED=12345 ./rogue
 ```
 
-The scoreboard is kept in `~/.rogue.scores`. Save files are Go gob
-snapshots and, as in the original, are deleted when restored.
+The scoreboard is kept in `~/.rogue.scores`. Save files are Go gob snapshots
+and, as in the original, are deleted when restored.
 
 ## Code layout
 
@@ -73,13 +72,17 @@ term/        tcell-backed terminal, replacing curses
 cmd/rogue/   the executable
 ```
 
-The engine package is fully headless-testable: `go test ./game/` runs
-scripted game sessions, dungeon-generation golden checks, and an RNG
-compatibility test against the original C generator.
+The engine package is fully headless-testable: `go test ./game/` runs scripted
+command sequences, dungeon-generation golden checks, and an RNG compatibility
+test against the original C generator.
+
+For development, the `Makefile` wraps the toolchain: `make fmt` (gofmt +
+prettier), `make lint` (golangci-lint), `make test`, and `make check` (all
+three).
 
 ## License
 
 BSD-style; see [LICENSE.TXT](LICENSE.TXT).
 
-Copyright (C) 1980-1983, 1985, 1999 Michael Toy, Ken Arnold and Glenn
-Wichman. All rights reserved.
+Copyright (C) 1980-1983, 1985, 1999 Michael Toy, Ken Arnold and Glenn Wichman.
+All rights reserved.

TODO.md

@@ -1,120 +1,188 @@
 # Workflow
 
-* branch (from `main`)
-* do the work in Next Step
-* move Next Step to the top of Completed Steps
-* move the top item of Future Steps into Next Step
-* commit (`TODO.md` changes in the same commit as the work)
-* merge to `main` if the branch is not protected, otherwise open a PR
-* push
+- branch (from `main`)
+- do the work in Next Step
+- move Next Step to the top of Completed Steps
+- move the top item of Future Steps into Next Step
+- commit (`TODO.md` changes in the same commit as the work)
+- merge to `main` if the branch is not protected, otherwise open a PR
+- push
 
 # Status
 
 pre-1.0
 
-The port on main is complete and faithful (function-by-function from
-Rogue 5.4.4 C; reference sources on c-master/modern-rogue). Current
-phase: refactor from a transliterated port into idiomatic Go — one
-feature branch per step below, descriptive naming, real types, house
-style per ~/dev/prompts/prompts/CODE_STYLEGUIDE_GO.md.
+The port on main is complete and faithful (function-by-function from Rogue 5.4.4
+C; reference sources on c-master/modern-rogue). Current phase: refactor from a
+transliterated port into idiomatic Go — one feature branch per step below,
+descriptive naming, real types, house style per
+~/dev/prompts/prompts/CODE_STYLEGUIDE_GO.md.
 
 Refactor ground rules:
 
-- Behavior must not change unless a step says so. The full test suite
-  (scripted sessions, generation invariants, C-compatible RNG goldens)
-  gates every step; 80x24 seed-compatible gameplay stays intact.
-- Renames keep the C lineage greppable: doc comments retain their
-  "(file.c func_name)" breadcrumbs, and the docs refresh step adds a
-  C-name → Go-name table to ARCHITECTURE.md.
+- Behavior must not change unless a step says so. The full test suite (scripted
+  sessions, generation invariants, C-compatible RNG goldens) gates every step;
+  80x24 seed-compatible gameplay stays intact.
+- Renames keep the C lineage greppable: doc comments retain their "(file.c
+  func_name)" breadcrumbs, and the docs refresh step adds a C-name → Go-name
+  table to ARCHITECTURE.md.
 
 # Next Step
 
-Refactor step 1 (branch refactor/descriptive-constants): rename
-constants to descriptive, less C-like names. Creature/object/room/place
-flag bits (IsHuh→Confused, IsHalu→Hallucinating, CanHuh→CanConfuse,
-SeeMonst→SenseMonsters, ObjIsFound→WasFound, IsCanc→Cancelled, ...),
-trap types (TMyst→TrapMystery), item subtype constants
-(PLSD→PotionLSD, SIDRorS→ScrollIdentifyRingOrStick,
-RAddHit→RingDexterity, WsHasteM→WandHasteMonster,
-TwoSword→WeaponTwoHandedSword, ...), Max* count constants →
-Num*Types, and the Level.NTraps field → TrapCount. Pure rename; no
-behavior change; tests unchanged.
+Broaden unit test coverage where playtesting finds thin spots (rings, sticks,
+wizard commands).
 
 # Completed Steps
 
+- 2026-07-24 Seed compatibility — item tables (seed-compat): instrumented the C
+  reference on modern-rogue with a DUMP mode (testdata/c_seedcompat.patch) that
+  forces the RNG seed and prints the per-seed item appearance tables (potion
+  colors, scroll names, ring stones, wand/staff materials) before initscr, and
+  captured its output for four seeds as testdata/item_tables.golden.
+  TestSeedCompatItemTables regenerates the same tables from the Go port and they
+  match byte for byte — proving the LCG and its consumption order through the
+  whole init sequence agree with C. The remaining "same dungeon (map)" half
+  would need the harder headless-curses C dump (new_level draws to curses);
+  deferred — the item-table match already validates RNG-order faithfulness
+  through init, and the Go generation goldens guard determinism thereafter.
+
+- 2026-07-23 Playtest hardening (playtest-hardening): added two death-safe
+  crash-sweep drives through the real turn loop, within the step-8 os.Exit
+  constraint (a fortify() helper pins HP/food/exp and clears the freeze/stuck
+  counters each turn so no death exits the test binary; fixed seeds keep them
+  deterministic). TestDeepPlaythrough uses quaff/read/zap through command
+  dispatch, then descends to depth 8 with a save/restore at depth 4;
+  TestTurnLoopCrashSweep mashes movement/search/rest for 200 turns on four
+  seeds. Neither surfaced a panic. The interactive "play several games at a real
+  tcell terminal" portion needs a human at an 80x24 terminal and is left to the
+  maintainer; the binary's non-interactive paths (`-s` scores) were
+  smoke-tested.
+
+- 2026-07-23 Docs refresh (docs-refresh): rewrote ARCHITECTURE.md Part 2 (the
+  pre-implementation design sketch) to match the final code — current type/field
+  names (ObjectKind, DiceSpec, split o_arm, step-1 flag names, TrapCount, Level
+  list methods), the static tables now on the per-game gameData struct, the
+  daemon/effect handler tables, the MessageLine extraction, the Terminal
+  interface, the flat gob SaveState, and the New(Params) + os.Exit design. Added
+  §7.1, a C-name → Go-name rename table, and a README note on the make targets.
+
+- 2026-07-23 Refactor step 8 (refactor/constructor-style): constructor and exit
+  pass. NewGame(Config) → New(Params) and Restore takes Params, so the package's
+  primary type gets the canonical New() constructor with a named-field Params
+  struct (styleguide 139/159). The gameEnd panic unwind is gone: one game run is
+  one process, so myExit restores the terminal (new Terminal.Fini) and calls
+  os.Exit(0), and Run() no longer returns; the four Run()-to-completion tests
+  were reworked/dropped since death (combat or starvation) now exits the process
+  (TestScoreRendersList and TestRunDownStairs preserve what is still drivable;
+  save/restore stays covered by TestSaveRestoreRoundTrip). The 77-column wrap
+  sweep was dropped per sneak (2026-07-23): line lengths left as-is (lll caps at
+  88 and passes).
+
+- 2026-07-07 Refactor step 7 (refactor/effects-dispatch): effects dispatch
+  tables plus a full decomposition sweep — the quaff / readScroll / doZap
+  switches, the attack monster-power switch, the be_trapped switch, the daemon
+  d_func switch, and the command-key switch all became handler tables on
+  gameData (quaffHandlers, readHandlers, zapHandlers, hitHandlers, trapHandlers,
+  daemonHandlers, commandHandlers), one small named method per case. Every
+  remaining cyclop/gocognit/nestif hot spot was split into named helpers across
+  fight, misc (look), command, chase, move, passages, options, pack, things,
+  save, daemons, rooms, score, monsters, rings, rip, io, object, weapons,
+  wizard, and term/tcell, plus three test functions. Effect order and RNG call
+  sequence preserved throughout; the whole golangci-lint run is now 0 issues.
+
+- 2026-07-07 Refactor step 6 (refactor/god-object-extraction): MessageLine (was
+  MsgLine) owns the msg/addmsg/endmsg machinery, wired to its screen/look/input
+  needs via attach(); RogueGame keeps one-line msg/addmsgf/endmsg shorthands so
+  call sites are unchanged. Player owns pack bookkeeping (nextPackChar,
+  removeFromPack — the state half of leave_pack; leavePack keeps only LastPick
+  tracking). Level owns object/monster list management and lookup (ObjectAt
+  replaces findObj; AddObject/RemoveObject/AddMonster/RemoveMonster replace
+  direct attachObj/detachObj/attachMon/detachMon on level lists).
+  Inventory/pickup UI flows stay on RogueGame deliberately: they are display and
+  turn orchestration, not state surgery.
+
+- 2026-07-07 Refactor step 5 (refactor/item-combat-ui-renames, three commits,
+  one subsystem each): items — getItem→promptPackItem now returning (obj, ok),
+  invName→inventoryName, doPot→applyPotionFuse; combat — rollEm→rollAttacks,
+  attack/moveMonster/chaseStep return (removed bool) instead of C -1/0 int
+  codes; UI — getDir→promptDirection. C breadcrumbs kept; suite green.
+
+- 2026-07-07 Refactor step 4 (refactor/movement-renames): movement/world renames
+  (doMove→moveHero, beTrapped→springTrap, rndmove→randomStep,
+  doRooms/doPassages/doMaze→digRooms/digPassages/digMaze, chgStr→changeStrength,
+  doRun→startRun, moveStuff→finishMove, turnref→turnRefresh,
+  moveMonst→moveMonster, doChase→chaseStep, setOldch→setOldChar, cansee→canSee,
+  roomin→roomIn, runto→runTo, conn→connectRooms, putpass→putPassage,
+  passnum→numberPassages, numpass→numberPassage, rndPos→randomPos,
+  rndRoom→randomRoom, treasRoom→treasureRoom, accntMaze→accountMaze); all
+  goto/label flows replaced with loops (moveHero retry loop + extracted
+  passageTurn, dispatch re-dispatch loop, chaseStep passage loop, saveGame
+  labeled prompt loop); C breadcrumbs kept in doc comments.
+- 2026-07-07 Lint adoption finished (refactor/no-package-globals): all 37
+  package-level vars moved into `gameData` (built by `newGameData`, hung on
+  RogueGame as `g.data`, set in NewGame and Restore); ObjectKind
+  Glyph()/objectKindForGlyph became switches; the table-reading subtype
+  Stringers were removed; isMagic became a RogueGame method; goconst fixed with
+  named word constants (potionName, goldName, staffName, ripWall, ...);
+  testpackage and exhaustive disabled in .golangci.yml with sneak's approval
+  (2026-07-07); misspell's corruption of the "ther" scroll syllable reverted.
+  mnd disabled with sneak's approval (2026-07-07, follow-up commit). Remaining
+  red: cyclop (36), nestif (30), gocognit (23) stay until step 7 fixes them per
+  sneak's ruling.
+- 2026-07-06 Lint adoption bulk (refactor/lint-adoption, 5ba9fe8): .golangci.yml
+  copied verbatim from the prompts repo (plus the sneak-approved paralleltest
+  exception, 2026-07-06); ~1,500 findings fixed (autofix formatting sweep,
+  errcheck/err113/noinlineerr error handling, forbidigo, funcorder, recvcheck
+  pointer receivers, goprintffuncname renames msg helpers to *f, revive doc
+  comments, gocritic switch rewrites, gosec real fixes plus justified nolints,
+  unparam signature tightening, C-faithful "missle" spellings restored after
+  misspell autofix changed game text).
+- 2026-07-06 Module base path updated to git.eeqj.de/sneak/rgoue (go.mod, term/
+  and cmd/ imports, ARCHITECTURE.md, version string).
+- 2026-07-06 Refactor step 3 (refactor/object-fields): Object.Arm split into
+  ArmorClass/Charges/GoldValue/Bonus (rings); Stats.Arm → ArmorClass; damage
+  strings parsed once into DiceSpec at table definition (ParseDice keeps C
+  roll_em parse semantics, incl. "%%%x0" and "000x0" edge cases,
+  regression-tested); save format 5.4.4-go3.
+- 2026-07-06 Refactor step 2 (refactor/typed-kinds, b940cfc): ObjectKind
+  separates item category from map glyph (Object.Type byte → Kind ObjectKind
+  with Glyph()); PotionKind/ScrollKind/RingKind/
+  WandKind/WeaponKind/ArmorKind/TrapKind typed iota enums with Stringer; typed
+  accessors on Object; getItem/inventory/whatis filters take ObjectKind
+  (KindCallable/KindRingOrStick replace CALLABLE/R_OR_S); save format bumped to
+  5.4.4-go2. Suite green.
+- 2026-07-06 Refactor step 1 (refactor/descriptive-constants): renamed all flag
+  bits, trap types, item subtype constants, and Max* counts to descriptive names
+  (IsHuh→Confused, SeeMonst→SenseMonsters, WsHasteM→WandHasteMonster,
+  MaxSticks→NumWandTypes, ...); Level.NTraps→TrapCount; C names kept as comment
+  breadcrumbs. Pure rename, suite green.
 - 2026-07-06 Made the rgoue branch Go-only: removed C sources and the
-  autoconf/VS build system (they remain on master and modern-rogue),
-  ported the last wizard command (item-probability listing), rewrote
-  README.md for the Go port (c0b533e)
-- 2026-07-06 Ported the command loop, save/restore, the tcell terminal
-  layer, and the playable binary at cmd/rogue (41fc104)
-- 2026-07-06 Ported item effects: potions, scrolls, options, call_it
-  (cdf9bf7)
-- 2026-07-06 Ported combat, the chase driver, traps, zapping, death and
-  scores (3c5add8)
-- 2026-07-06 Ported dungeon generation, base items, the pack, and
-  monster creation (a69ef7d)
-- 2026-07-06 Ported the foundation: types, seed-compatible RNG, item
-  tables, daemon scheduler (7fa2048)
-- 2026-07-06 Wrote ARCHITECTURE.md Parts 1 and 2: complete map of the C
-  program and the Go port design (91eeee0, 45dba95)
-- Fork base: Davidslv/rogue C 5.4.4 with modernization fixes (C23
-  prototypes, ncurses compat), preserved on master/modern-rogue
+  autoconf/VS build system (they remain on master and modern-rogue), ported the
+  last wizard command (item-probability listing), rewrote README.md for the Go
+  port (c0b533e)
+- 2026-07-06 Ported the command loop, save/restore, the tcell terminal layer,
+  and the playable binary at cmd/rogue (41fc104)
+- 2026-07-06 Ported item effects: potions, scrolls, options, call_it (cdf9bf7)
+- 2026-07-06 Ported combat, the chase driver, traps, zapping, death and scores
+  (3c5add8)
+- 2026-07-06 Ported dungeon generation, base items, the pack, and monster
+  creation (a69ef7d)
+- 2026-07-06 Ported the foundation: types, seed-compatible RNG, item tables,
+  daemon scheduler (7fa2048)
+- 2026-07-06 Wrote ARCHITECTURE.md Parts 1 and 2: complete map of the C program
+  and the Go port design (91eeee0, 45dba95)
+- Fork base: Davidslv/rogue C 5.4.4 with modernization fixes (C23 prototypes,
+  ncurses compat), preserved on master/modern-rogue
 
 # Future Steps
 
-1. Refactor step 2: typed kind enums — PotionKind, ScrollKind,
-   RingKind, WandKind, WeaponKind, ArmorKind, TrapKind as iota enums
-   with fmt.Stringer; Object.Which and the ObjInfo tables move to the
-   typed kinds; the object category glyph bytes ('!', '?', ...) become
-   an ObjectKind with a Glyph() method so item category and map
-   character stop sharing one byte namespace.
-2. Refactor step 3: un-overload Object fields — split Object.Arm into
-   ArmorClass/Charges/GoldValue; parse damage dice ("1x4/1x2") once
-   into a DiceSpec type at table definition instead of per swing;
-   save-format update with round-trip test migration.
-3. Adopt the house Go linting standards: copy .golangci.yml from the
-   prompts repo and bring game/, term/, and cmd/ lint-clean (the port
-   is greenfield code, so no exemptions apply).
-4. Refactor step 4: method renames, movement/world subsystem
-   (doMove→moveHero, beTrapped→springTrap, rndmove→randomStep,
-   doRooms/doPassages/doMaze→digRooms/digPassages/digMaze,
-   chgStr→changeStrength, ...); remove the goto/label flows in doMove,
-   dispatch, and saveGame in favor of loops and helpers.
-5. Refactor step 5: method renames, items/combat/UI subsystems
-   (invName→inventoryName, rollEm→rollAttacks, doPot→applyPotionFuse,
-   getItem→promptPackItem returning (obj, ok), getDir→promptDirection);
-   int status codes (attack returning -1) become named results. Two or
-   three commits, one subsystem each.
-6. Refactor step 6: extract types from the god object — MessageLine
-   owns the msg/addmsg/endmsg machinery; pack/inventory operations move
-   onto *Player; monster/object list management and map queries
-   consolidate onto *Level; RogueGame keeps turn orchestration and
-   cross-system effects only.
-7. Refactor step 7: effects dispatch — the giant quaff/readScroll/doZap
-   switches become per-kind handler tables of small named methods,
-   keeping effect order and RNG call sequence identical.
-8. Refactor step 8: constructor and style pass per the house
-   styleguide — game.New(game.Params{...}) replacing NewGame(Config);
-   replace the gameEnd panic unwind with error-based turn results where
-   feasible; 77-column wrap sweep.
-9. Docs refresh: update ARCHITECTURE.md Part 2 and README.md for the
-   post-refactor names; add the C name → Go name rename table.
-10. Playtest hardening pass: play several full games with the tcell
-    binary and extend run_test.go to script a deeper multi-level
-    playthrough (descend past level 5, use potions, scrolls, zapping,
-    save/restore). Fix any panics, message mismatches, or divergences
-    from the C behavior that this uncovers, with regression tests.
-11. Verify the seed-compatibility claim against the C reference on
-    c-master: same seed, same dungeon, same item tables, for several
-    seeds.
-12. Broaden unit test coverage where playtesting finds thin spots
-    (rings, sticks, wizard commands).
-13. Tag a release once a full game (Amulet retrieval and score entry)
-    completes without defects.
-14. Full-terminal-size support (deferred by explicit decision
-    2026-07-06): per-game dungeon dimensions instead of the 80x24
-    constants; open design questions are resize policy, gameplay
-    tuning at larger sizes, and a --classic 80x24 mode.
-15. Note: this repo is exempt from the standard policy scaffold. Do not
-    add Makefile, Dockerfile, or REPO_POLICIES.md.
+1. Tag a release once a full game (Amulet retrieval and score entry) completes
+   without defects.
+2. Full-terminal-size support (deferred by explicit decision 2026-07-06):
+   per-game dungeon dimensions instead of the 80x24 constants; open design
+   questions are resize policy, gameplay tuning at larger sizes, and a --classic
+   80x24 mode.
+3. Note: this repo is exempt from the standard policy scaffold. A minimal dev
+   Makefile (fmt/fmt-check/lint/test/check targets) exists per sneak's
+   2026-07-07 request, but do not add a Dockerfile, CI config, or
+   REPO_POLICIES.md.

cmd/rogue/main.go

@@ -13,89 +13,121 @@ import (
 	"syscall"
 	"time"
 
-	"sneak.berlin/go/rogue/game"
-	"sneak.berlin/go/rogue/term"
+	"git.eeqj.de/sneak/rgoue/game"
+	"git.eeqj.de/sneak/rgoue/term"
 )
 
 func main() {
+	os.Exit(run())
+}
+
+// run does the real work and returns an exit code. It only returns on a
+// startup error; once the game starts, it ends by exiting the process
+// from within (game.myExit restores the terminal first). The deferred
+// Fini covers the early-return paths.
+func run() int {
 	scores := flag.Bool("s", false, "print the scoreboard and exit")
 	deathDemo := flag.Bool("d", false, "die a random death (demo)")
+
 	flag.Parse()
 
-	home, _ := os.UserHomeDir()
-
-	// get options from environment (main.c)
-	rogueOpts := os.Getenv("ROGUEOPTS")
-	name := ""
-	if u, err := user.Current(); err == nil {
-		name = u.Username
-	}
-
-	wizard := os.Getenv("ROGUE_WIZARD") != ""
-	// dungeon number: SEED for reproducible dungeons (wizard mode in C),
-	// else time+pid
-	var seed int32
-	if env := os.Getenv("SEED"); env != "" && wizard {
-		n, _ := strconv.Atoi(env)
-		seed = int32(n)
-	} else {
-		seed = int32(time.Now().Unix()) + int32(os.Getpid())
-	}
-
-	cfg := game.Config{
-		Seed:      seed,
-		Name:      name,
-		RogueOpts: rogueOpts,
-		Home:      home,
-		ScorePath: home + "/.rogue.scores",
-		Wizard:    wizard,
-	}
+	params := loadParams()
 
 	if *scores {
-		g := game.NewGame(cfg)
-		g.ShowScores()
-		return
+		game.New(params).ShowScores()
+
+		return 0
 	}
 
 	t, err := term.New()
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
+
+		return 1
 	}
 	defer t.Fini()
-	cfg.Term = t
+
+	params.Term = t
 
 	var g *game.RogueGame
+
 	if args := flag.Args(); len(args) == 1 && !*deathDemo {
 		// restore a saved game
-		g, err = game.Restore(args[0], cfg)
+		g, err = game.Restore(args[0], params)
 		if err != nil {
-			t.Fini()
-			fmt.Fprintln(os.Stderr, err)
-			os.Exit(1)
+			fmt.Fprintln(os.Stderr, err) // deferred Fini restores the terminal
+
+			return 1
 		}
 	} else {
-		g = game.NewGame(cfg)
+		g = game.New(params)
 	}
 
 	if *deathDemo {
-		g.DeathDemo()
-		return
+		g.DeathDemo() // does not return: death exits the process
+
+		return 0
 	}
 
-	// SIGHUP/SIGTERM autosave (save.c auto_save)
+	installAutosave(g, t)
+
+	g.Run() // does not return: the game ends by exiting the process
+
+	return 0
+}
+
+// loadParams gathers the game parameters from the environment: home
+// directory, ROGUEOPTS, user name, wizard mode, and the dungeon seed
+// (main.c's startup).
+func loadParams() game.Params {
+	home, _ := os.UserHomeDir()
+
+	name := ""
+
+	u, userErr := user.Current()
+	if userErr == nil {
+		name = u.Username
+	}
+
+	wizard := os.Getenv("ROGUE_WIZARD") != ""
+
+	return game.Params{
+		Seed:      chooseSeed(wizard),
+		Name:      name,
+		RogueOpts: os.Getenv("ROGUEOPTS"),
+		Home:      home,
+		ScorePath: home + "/.rogue.scores",
+		Wizard:    wizard,
+	}
+}
+
+// installAutosave saves the game and exits on SIGHUP/SIGTERM (save.c
+// auto_save).
+func installAutosave(g *game.RogueGame, t *term.Tcell) {
 	sig := make(chan os.Signal, 1)
+
 	signal.Notify(sig, syscall.SIGHUP, syscall.SIGTERM)
+
 	go func() {
 		<-sig
 		g.AutoSave()
 		t.Fini()
 		os.Exit(0)
 	}()
-
-	if err := g.Run(); err != nil {
-		t.Fini()
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
+}
+
+// chooseSeed picks the dungeon number: SEED for reproducible dungeons
+// (wizard mode, as in the C game), else time+pid (main.c).
+func chooseSeed(wizard bool) int32 {
+	if env := os.Getenv("SEED"); env != "" && wizard {
+		n, err := strconv.ParseInt(env, 10, 32)
+		if err == nil {
+			return int32(n)
+		}
+	}
+
+	// The C game computed `lowtime + getpid()` in int; the truncation to
+	// 32 bits is the same wraparound the C int arithmetic performed.
+	return int32(time.Now().Unix()&0x7fffffff) +
+		int32(os.Getpid()&0x7fffffff)
 }

game/armor.go

@@ -5,36 +5,47 @@ package game
 // wear lets the player put armor on (armor.c wear).
 func (g *RogueGame) wear() {
 	p := &g.Player
-	obj := g.getItem("wear", int(Armor))
-	if obj == nil {
+
+	obj, ok := g.promptPackItem("wear", KindArmor)
+	if !ok {
 		return
 	}
+
 	if p.CurArmor != nil {
-		g.addmsg("you are already wearing some")
+		g.addmsgf("you are already wearing some")
+
 		if !g.Options.Terse {
-			g.addmsg(".  You'll have to take it off first")
+			g.addmsgf(".  You'll have to take it off first")
 		}
+
 		g.endmsg()
 		g.After = false
+
 		return
 	}
-	if obj.Type != Armor {
+
+	if obj.Kind != KindArmor {
 		g.msg("you can't wear that")
+
 		return
 	}
+
 	g.wasteTime()
-	obj.Flags.Set(IsKnow)
-	sp := g.invName(obj, true)
+	obj.Flags.Set(Known)
+	sp := g.inventoryName(obj, true)
 	p.CurArmor = obj
+
 	if !g.Options.Terse {
-		g.addmsg("you are now ")
+		g.addmsgf("you are now ")
 	}
+
 	g.msg("wearing %s", sp)
 }
 
 // takeOff gets the armor off of the player's back (armor.c take_off).
 func (g *RogueGame) takeOff() {
 	p := &g.Player
+
 	obj := p.CurArmor
 	if obj == nil {
 		g.After = false
@@ -43,18 +54,23 @@ func (g *RogueGame) takeOff() {
 		} else {
 			g.msg("you aren't wearing any armor")
 		}
+
 		return
 	}
+
 	if !g.dropCheck(p.CurArmor) {
 		return
 	}
+
 	p.CurArmor = nil
+
 	if g.Options.Terse {
-		g.addmsg("was")
+		g.addmsgf("was")
 	} else {
-		g.addmsg("you used to be")
+		g.addmsgf("you used to be")
 	}
-	g.msg(" wearing %c) %s", obj.PackCh, g.invName(obj, true))
+
+	g.msg(" wearing %c) %s", obj.PackCh, g.inventoryName(obj, true))
 }
 
 // wasteTime does nothing but let other things happen (armor.c waste_time).

game/chase.go

@@ -9,44 +9,61 @@ const dragonShot = 5
 func (g *RogueGame) runners(int) {
 	list := append([]*Monster(nil), g.Level.Monsters...)
 	for _, tp := range list {
-		if !tp.On(IsHeld) && tp.On(IsRun) {
-			origPos := tp.Pos
-			wastarget := tp.On(IsTarget)
-			if g.moveMonst(tp) == -1 {
-				continue
-			}
-			if tp.On(IsFly) && distCp(g.Player.Pos, tp.Pos) >= 3 {
-				if g.moveMonst(tp) == -1 {
-					continue
-				}
-			}
-			if wastarget && origPos != tp.Pos {
-				tp.Flags.Clear(IsTarget)
-				g.ToDeath = false
-			}
-		}
+		g.runnerTurn(tp)
 	}
+
 	if g.HasHit {
 		g.endmsg()
 		g.HasHit = false
 	}
 }
 
-// moveMonst executes a single turn of running for a monster (chase.c
-// move_monst). Returns -1 if the monster died or left the level.
-func (g *RogueGame) moveMonst(tp *Monster) int {
-	if !tp.On(IsSlow) || tp.Turn {
-		if g.doChase(tp) == -1 {
-			return -1
+// runnerTurn gives one monster its motion for the turn; flying monsters
+// far from the hero move twice (the loop body of chase.c runners).
+func (g *RogueGame) runnerTurn(tp *Monster) {
+	if tp.On(Held) || !tp.On(Awake) {
+		return
+	}
+
+	origPos := tp.Pos
+
+	wastarget := tp.On(Targeted)
+	if removed := g.moveMonster(tp); removed {
+		return
+	}
+
+	if tp.On(Flying) && distCp(g.Player.Pos, tp.Pos) >= 3 {
+		if removed := g.moveMonster(tp); removed {
+			return
 		}
 	}
-	if tp.On(IsHaste) {
-		if g.doChase(tp) == -1 {
-			return -1
+
+	if wastarget && origPos != tp.Pos {
+		tp.Flags.Clear(Targeted)
+
+		g.ToDeath = false
+	}
+}
+
+// moveMonster executes a single turn of running for a monster (chase.c
+// move_monst). The result reports that the monster died or left the
+// level (the C -1 return).
+func (g *RogueGame) moveMonster(tp *Monster) bool {
+	if !tp.On(Slowed) || tp.Turn {
+		if g.chaseStep(tp) {
+			return true
 		}
 	}
+
+	if tp.On(Hasted) {
+		if g.chaseStep(tp) {
+			return true
+		}
+	}
+
 	tp.Turn = !tp.Turn
-	return 0
+
+	return false
 }
 
 // relocate makes the monster's new location be the specified one, updating
@@ -54,52 +71,104 @@ func (g *RogueGame) moveMonst(tp *Monster) int {
 func (g *RogueGame) relocate(th *Monster, newLoc Coord) {
 	if newLoc != th.Pos {
 		g.mvaddch(th.Pos.Y, th.Pos.X, th.OldCh)
-		th.Room = g.roomin(newLoc)
-		g.setOldch(th, newLoc)
+		th.Room = g.roomIn(newLoc)
+		g.setOldChar(th, newLoc)
 		oroom := th.Room
 		g.Level.SetMonsterAt(th.Pos.Y, th.Pos.X, nil)
 
 		if oroom != th.Room {
 			th.Dest = g.findDest(th)
 		}
+
 		th.Pos = newLoc
 		g.Level.SetMonsterAt(newLoc.Y, newLoc.X, th)
 	}
+
 	g.move(newLoc.Y, newLoc.X)
+
 	if g.seeMonst(th) {
 		g.addch(th.Disguise)
-	} else if g.Player.On(SeeMonst) {
+	} else if g.Player.On(SenseMonsters) {
 		g.standout()
 		g.addch(th.Type)
 		g.standend()
 	}
 }
 
-// doChase makes one thing chase another (chase.c do_chase). Returns -1 if
-// the chaser died in the attempt.
-func (g *RogueGame) doChase(th *Monster) int {
-	p := &g.Player
+// chaseStep makes one thing chase another (chase.c do_chase). The
+// result reports that the chaser died or left the level in the attempt
+// (the C -1 return).
+func (g *RogueGame) chaseStep(th *Monster) bool {
 	stoprun := false // true means we are there
-	mindist := 32767
+
+	rer, ree, door := g.chaseRooms(th)
+
+	this, shot := g.chaseGoal(th, rer, ree, door, 32767)
+	if shot {
+		return false
+	}
+	// This now contains what we want to run to this time so we run to it.
+	// If we hit it we either want to fight it or stop running
+	if g.chase(th, this) {
+		if th.Type == 'F' {
+			return false
+		}
+	} else {
+		switch this {
+		case g.Player.Pos:
+			return g.attack(th)
+		case *th.Dest:
+			g.chaseTakeObject(th)
+
+			stoprun = th.Type != 'F'
+		}
+	}
+
+	g.relocate(th, g.chRet)
+	// And stop running if need be
+	if stoprun && th.Pos == *th.Dest {
+		th.Flags.Clear(Awake)
+	}
+
+	return false
+}
+
+// chaseRooms finds the rooms of the chaser and its desire; doors do not
+// count as inside rooms here (the setup of chase.c do_chase).
+func (g *RogueGame) chaseRooms(th *Monster) (*Room, *Room, bool) {
+	p := &g.Player
 
 	rer := th.Room // find room of chaser
-	if th.On(IsGreed) && rer.GoldVal == 0 {
+	if th.On(Greedy) && rer.GoldVal == 0 {
 		th.Dest = &p.Pos // if gold has been taken, run after hero
 	}
+
 	var ree *Room // find room of chasee
 	if th.Dest == &p.Pos {
 		ree = p.Room
 	} else {
-		ree = g.roomin(*th.Dest)
+		ree = g.roomIn(*th.Dest)
 	}
-	// We don't count doors as inside rooms for this routine
-	door := g.Level.Char(th.Pos.Y, th.Pos.X) == Door
+
+	return rer, ree, g.Level.Char(th.Pos.Y, th.Pos.X) == Door
+}
+
+// chaseGoal picks the spot the chaser runs toward this turn: the
+// nearest exit toward its desire when it is in a different room, or the
+// desire itself. shot means a dragon breathed flame instead of moving
+// (the goal loop of chase.c do_chase).
+func (g *RogueGame) chaseGoal(th *Monster, rer, ree *Room, door bool, mindist int) (Coord, bool) {
 	var this Coord
 
-over:
-	// If the object of our desire is in a different room, and we are not
-	// in a corridor, run to the door nearest to our goal.
-	if rer != ree {
+	for {
+		// If the object of our desire is in a different room, and we are
+		// not in a corridor, run to the door nearest to our goal.
+		if rer == ree {
+			this = *th.Dest
+
+			return this, g.dragonBreath(th)
+		}
+
 		for i := range rer.Exits {
 			curdist := distCp(*th.Dest, rer.Exits[i])
 			if curdist < mindist {
@@ -107,169 +176,206 @@ over:
 				mindist = curdist
 			}
 		}
-		if door {
-			rer = &g.Level.Passages[*g.Level.FlagsAt(th.Pos.Y, th.Pos.X)&FPNum]
-			door = false
-			goto over
+
+		if !door {
+			return this, false
 		}
-	} else {
-		this = *th.Dest
-		// For dragons check and see if (a) the hero is on a straight line
-		// from it, and (b) that it is within shooting distance, but
-		// outside of striking range.
-		if th.Type == 'D' && (th.Pos.Y == p.Pos.Y || th.Pos.X == p.Pos.X ||
-			abs(th.Pos.Y-p.Pos.Y) == abs(th.Pos.X-p.Pos.X)) &&
-			distCp(th.Pos, p.Pos) <= BoltLength*BoltLength &&
-			!th.On(IsCanc) && g.rnd(dragonShot) == 0 {
-			g.Delta.Y = sign(p.Pos.Y - th.Pos.Y)
-			g.Delta.X = sign(p.Pos.X - th.Pos.X)
-			if g.HasHit {
-				g.endmsg()
+
+		rer = &g.Level.Passages[*g.Level.FlagsAt(th.Pos.Y, th.Pos.X)&FPassNum]
+		door = false
+		// the C goto over: redo with the passage as room
+	}
+}
+
+// dragonBreath checks whether a dragon shoots flame at the hero instead
+// of moving, and shoots it (the D block of chase.c do_chase).
+func (g *RogueGame) dragonBreath(th *Monster) bool {
+	if th.Type != 'D' || !g.dragonShoots(th) {
+		return false
+	}
+
+	p := &g.Player
+
+	g.Delta.Y = sign(p.Pos.Y - th.Pos.Y)
+
+	g.Delta.X = sign(p.Pos.X - th.Pos.X)
+	if g.HasHit {
+		g.endmsg()
+	}
+
+	g.fireBolt(th.Pos, &g.Delta, "flame")
+	g.Running = false
+	g.Count = 0
+
+	g.Quiet = 0
+	if g.ToDeath && !th.On(Targeted) {
+		g.ToDeath = false
+		g.Kamikaze = false
+	}
+
+	return true
+}
+
+// dragonShoots decides whether the dragon takes the shot: the hero is
+// on a straight line from it, within shooting distance but outside
+// striking range, it is not cancelled, and the shot roll comes up
+// (chase.c do_chase).
+func (g *RogueGame) dragonShoots(th *Monster) bool {
+	p := &g.Player
+	if th.Pos.Y != p.Pos.Y && th.Pos.X != p.Pos.X &&
+		abs(th.Pos.Y-p.Pos.Y) != abs(th.Pos.X-p.Pos.X) {
+		return false
+	}
+
+	return distCp(th.Pos, p.Pos) <= BoltLength*BoltLength &&
+		!th.On(Cancelled) && g.rnd(dragonShot) == 0
+}
+
+// chaseTakeObject has the monster pick up the object it was running to
+// (the dest arm of chase.c do_chase).
+func (g *RogueGame) chaseTakeObject(th *Monster) {
+	for _, obj := range g.Level.Objects {
+		if th.Dest == &obj.Pos {
+			g.Level.RemoveObject(obj)
+			attachObj(&th.Pack, obj)
+
+			if th.Room.Flags.Has(Gone) {
+				g.Level.SetChar(obj.Pos.Y, obj.Pos.X, Passage)
+			} else {
+				g.Level.SetChar(obj.Pos.Y, obj.Pos.X, Floor)
 			}
-			g.fireBolt(th.Pos, &g.Delta, "flame")
-			g.Running = false
-			g.Count = 0
-			g.Quiet = 0
-			if g.ToDeath && !th.On(IsTarget) {
-				g.ToDeath = false
-				g.Kamikaze = false
-			}
-			return 0
+
+			th.Dest = g.findDest(th)
+
+			break
 		}
 	}
-	// This now contains what we want to run to this time so we run to it.
-	// If we hit it we either want to fight it or stop running
-	if !g.chase(th, this) {
-		if this == p.Pos {
-			return g.attack(th)
-		} else if this == *th.Dest {
-			for _, obj := range g.Level.Objects {
-				if th.Dest == &obj.Pos {
-					detachObj(&g.Level.Objects, obj)
-					attachObj(&th.Pack, obj)
-					if th.Room.Flags.Has(IsGone) {
-						g.Level.SetChar(obj.Pos.Y, obj.Pos.X, Passage)
-					} else {
-						g.Level.SetChar(obj.Pos.Y, obj.Pos.X, Floor)
-					}
-					th.Dest = g.findDest(th)
-					break
-				}
-			}
-			if th.Type != 'F' {
-				stoprun = true
-			}
-		}
-	} else {
-		if th.Type == 'F' {
-			return 0
-		}
-	}
-	g.relocate(th, g.chRet)
-	// And stop running if need be
-	if stoprun && th.Pos == *th.Dest {
-		th.Flags.Clear(IsRun)
-	}
-	return 0
 }
 
 // chase finds the spot for the chaser to move closer to the chasee
 // (chase.c chase). Returns true if we want to keep on chasing later, false
 // if we reach the goal. The chosen spot lands in g.chRet.
 func (g *RogueGame) chase(tp *Monster, ee Coord) bool {
-	p := &g.Player
-	er := tp.Pos
-	plcnt := 1
 	var curdist int
 
 	// If the thing is confused, let it move randomly. Invisible Stalkers
 	// are slightly confused all of the time, and bats are quite confused
 	// all the time
-	if (tp.On(IsHuh) && g.rnd(5) != 0) || (tp.Type == 'P' && g.rnd(5) == 0) ||
+	if (tp.On(Confused) && g.rnd(5) != 0) || (tp.Type == 'P' && g.rnd(5) == 0) ||
 		(tp.Type == 'B' && g.rnd(2) == 0) {
 		// get a valid random move
-		g.chRet = g.rndmove(&tp.Creature)
+		g.chRet = g.randomStep(&tp.Creature)
 		curdist = distCp(g.chRet, ee)
 		// Small chance that it will become un-confused
 		if g.rnd(20) == 0 {
-			tp.Flags.Clear(IsHuh)
+			tp.Flags.Clear(Confused)
 		}
 	} else {
-		// Otherwise, find the empty spot next to the chaser that is
-		// closest to the chasee. This will eventually hold where we move
-		// to get closer. If we can't find an empty spot, we stay where we
-		// are.
-		curdist = distCp(er, ee)
-		g.chRet = er
-
-		ey := er.Y + 1
-		if ey >= NumLines-1 {
-			ey = NumLines - 2
-		}
-		ex := er.X + 1
-		if ex >= NumCols {
-			ex = NumCols - 1
-		}
-
-		for x := er.X - 1; x <= ex; x++ {
-			if x < 0 {
-				continue
-			}
-			for y := er.Y - 1; y <= ey; y++ {
-				tryp := Coord{X: x, Y: y}
-				if !g.diagOk(er, tryp) {
-					continue
-				}
-				ch := g.Level.VisibleChar(y, x)
-				if stepOk(ch) {
-					// If it is a scroll, it might be a scare monster
-					// scroll so we need to look it up to see what type
-					// it is.
-					if ch == Scroll {
-						var found *Object
-						for _, obj := range g.Level.Objects {
-							if y == obj.Pos.Y && x == obj.Pos.X {
-								found = obj
-								break
-							}
-						}
-						if found != nil && found.Which == SScare {
-							continue
-						}
-					}
-					// It can also be a Xeroc, which we shouldn't step on
-					if m := g.Level.MonsterAt(y, x); m != nil && m.Type == 'X' {
-						continue
-					}
-					// If we didn't find any scrolls at this place or it
-					// wasn't a scare scroll, then this place counts
-					thisdist := distance(y, x, ee.Y, ee.X)
-					if thisdist < curdist {
-						plcnt = 1
-						g.chRet = tryp
-						curdist = thisdist
-					} else if thisdist == curdist {
-						if plcnt++; g.rnd(plcnt) == 0 {
-							g.chRet = tryp
-							curdist = thisdist
-						}
-					}
-				}
-			}
-		}
+		curdist = g.chaseBestSpot(tp, ee)
 	}
-	return curdist != 0 && g.chRet != p.Pos
+
+	return curdist != 0 && g.chRet != g.Player.Pos
 }
 
-// setOldch sets the oldch character for the monster (chase.c set_oldch).
-func (g *RogueGame) setOldch(tp *Monster, cp Coord) {
+// chaseSearch is the scan state while chase looks for the step that
+// gets a monster closest to its chasee.
+type chaseSearch struct {
+	er      Coord // where the chaser is
+	ee      Coord // where it wants to go
+	curdist int
+	plcnt   int
+}
+
+// chaseBestSpot finds the empty spot next to the chaser that is closest
+// to the chasee, leaving it in g.chRet; if there is none, the chaser
+// stays where it is (the search half of chase.c chase).
+func (g *RogueGame) chaseBestSpot(tp *Monster, ee Coord) int {
+	er := tp.Pos
+	s := chaseSearch{er: er, ee: ee, curdist: distCp(er, ee), plcnt: 1}
+	g.chRet = er
+
+	ey := er.Y + 1
+	if ey >= NumLines-1 {
+		ey = NumLines - 2
+	}
+
+	ex := er.X + 1
+	if ex >= NumCols {
+		ex = NumCols - 1
+	}
+
+	for x := er.X - 1; x <= ex; x++ {
+		if x < 0 {
+			continue
+		}
+
+		for y := er.Y - 1; y <= ey; y++ {
+			g.chaseTry(&s, y, x)
+		}
+	}
+
+	return s.curdist
+}
+
+// chaseTry scores one candidate square, reservoir-sampling among ties
+// (the scan body of chase.c chase).
+func (g *RogueGame) chaseTry(s *chaseSearch, y, x int) {
+	tryp := Coord{X: x, Y: y}
+	if !g.diagOk(s.er, tryp) {
+		return
+	}
+
+	ch := g.Level.VisibleChar(y, x)
+	if !stepOk(ch) {
+		return
+	}
+	// If it is a scroll, it might be a scare monster scroll so we need
+	// to look it up to see what type it is.
+	if ch == Scroll && g.scareScrollAt(y, x) {
+		return
+	}
+	// It can also be a Xeroc, which we shouldn't step on
+	if m := g.Level.MonsterAt(y, x); m != nil && m.Type == 'X' {
+		return
+	}
+	// If we didn't find any scrolls at this place or it wasn't a scare
+	// scroll, then this place counts
+	thisdist := distance(y, x, s.ee.Y, s.ee.X)
+	if thisdist < s.curdist {
+		s.plcnt = 1
+		g.chRet = tryp
+		s.curdist = thisdist
+	} else if thisdist == s.curdist {
+		if s.plcnt++; g.rnd(s.plcnt) == 0 {
+			g.chRet = tryp
+			s.curdist = thisdist
+		}
+	}
+}
+
+// scareScrollAt reports whether the object lying at (y, x) is a scare
+// monster scroll (chase.c chase).
+func (g *RogueGame) scareScrollAt(y, x int) bool {
+	for _, obj := range g.Level.Objects {
+		if y == obj.Pos.Y && x == obj.Pos.X {
+			return obj.ScrollKind() == ScrollScareMonster
+		}
+	}
+
+	return false
+}
+
+// setOldChar sets the oldch character for the monster (chase.c set_oldch).
+func (g *RogueGame) setOldChar(tp *Monster, cp Coord) {
 	if tp.Pos == cp {
 		return
 	}
+
 	sch := tp.OldCh
+
 	tp.OldCh = g.mvinch(cp.Y, cp.X)
-	if !g.Player.On(IsBlind) {
-		if (sch == Floor || tp.OldCh == Floor) && tp.Room.Flags.Has(IsDark) {
+	if !g.Player.On(Blind) {
+		if (sch == Floor || tp.OldCh == Floor) && tp.Room.Flags.Has(Dark) {
 			tp.OldCh = ' '
 		} else if distCp(cp, g.Player.Pos) <= LampDist && g.Options.SeeFloor {
 			tp.OldCh = g.Level.Char(cp.Y, cp.X)
@@ -281,44 +387,49 @@ func (g *RogueGame) setOldch(tp *Monster, cp Coord) {
 // see_monst).
 func (g *RogueGame) seeMonst(mp *Monster) bool {
 	p := &g.Player
-	if p.On(IsBlind) {
+	if p.On(Blind) {
 		return false
 	}
-	if mp.On(IsInvis) && !p.On(CanSee) {
+
+	if mp.On(Invisible) && !p.On(CanSeeInvisible) {
 		return false
 	}
+
 	y, x := mp.Pos.Y, mp.Pos.X
 	if distance(y, x, p.Pos.Y, p.Pos.X) < LampDist {
 		if y != p.Pos.Y && x != p.Pos.X &&
 			!stepOk(g.Level.Char(y, p.Pos.X)) && !stepOk(g.Level.Char(p.Pos.Y, x)) {
 			return false
 		}
+
 		return true
 	}
+
 	if mp.Room != p.Room {
 		return false
 	}
-	return !mp.Room.Flags.Has(IsDark)
+
+	return !mp.Room.Flags.Has(Dark)
 }
 
-// runto sets a monster running after the hero (chase.c runto).
-func (g *RogueGame) runto(runner Coord) {
+// runTo sets a monster running after the hero (chase.c runto).
+func (g *RogueGame) runTo(runner Coord) {
 	tp := g.Level.MonsterAt(runner.Y, runner.X)
 	if tp == nil {
 		return
 	}
 	// Start the beastie running
-	tp.Flags.Set(IsRun)
-	tp.Flags.Clear(IsHeld)
+	tp.Flags.Set(Awake)
+	tp.Flags.Clear(Held)
 	tp.Dest = g.findDest(tp)
 }
 
-// roomin finds what room some coordinates are in; nil means they aren't in
+// roomIn finds what room some coordinates are in; nil means they aren't in
 // any room (chase.c roomin).
-func (g *RogueGame) roomin(cp Coord) *Room {
+func (g *RogueGame) roomIn(cp Coord) *Room {
 	fp := *g.Level.FlagsAt(cp.Y, cp.X)
-	if fp.Has(FPass) {
-		return &g.Level.Passages[fp&FPNum]
+	if fp.Has(FPassage) {
+		return &g.Level.Passages[fp&FPassNum]
 	}
 
 	for i := range g.Level.Rooms {
@@ -330,6 +441,7 @@ func (g *RogueGame) roomin(cp Coord) *Room {
 	}
 
 	g.msg("in some bizarre place (%d, %d)", cp.Y, cp.X)
+
 	return nil
 }
 
@@ -338,33 +450,38 @@ func (g *RogueGame) diagOk(sp, ep Coord) bool {
 	if ep.X < 0 || ep.X >= NumCols || ep.Y <= 0 || ep.Y >= NumLines-1 {
 		return false
 	}
+
 	if ep.X == sp.X || ep.Y == sp.Y {
 		return true
 	}
+
 	return stepOk(g.Level.Char(ep.Y, sp.X)) && stepOk(g.Level.Char(sp.Y, ep.X))
 }
 
-// cansee returns true if the hero can see a certain coordinate (chase.c
+// canSee returns true if the hero can see a certain coordinate (chase.c
 // cansee).
-func (g *RogueGame) cansee(y, x int) bool {
+func (g *RogueGame) canSee(y, x int) bool {
 	p := &g.Player
-	if p.On(IsBlind) {
+	if p.On(Blind) {
 		return false
 	}
+
 	if distance(y, x, p.Pos.Y, p.Pos.X) < LampDist {
-		if g.Level.FlagsAt(y, x).Has(FPass) {
+		if g.Level.FlagsAt(y, x).Has(FPassage) {
 			if y != p.Pos.Y && x != p.Pos.X &&
 				!stepOk(g.Level.Char(y, p.Pos.X)) &&
 				!stepOk(g.Level.Char(p.Pos.Y, x)) {
 				return false
 			}
 		}
+
 		return true
 	}
 	// We can only see if the hero is in the same room as the coordinate
 	// and the room is lit, or if it is close.
-	rer := g.roomin(Coord{X: x, Y: y})
-	return rer == p.Room && !rer.Flags.Has(IsDark)
+	rer := g.roomIn(Coord{X: x, Y: y})
+
+	return rer == p.Room && !rer.Flags.Has(Dark)
 }
 
 // findDest finds the proper destination for the monster (chase.c
@@ -374,22 +491,29 @@ func (g *RogueGame) findDest(tp *Monster) *Coord {
 	if prob <= 0 || tp.Room == g.Player.Room || g.seeMonst(tp) {
 		return &g.Player.Pos
 	}
+
 	for _, obj := range g.Level.Objects {
-		if obj.Type == Scroll && obj.Which == SScare {
+		if obj.Kind == KindScroll && obj.ScrollKind() == ScrollScareMonster {
 			continue
 		}
-		if g.roomin(obj.Pos) == tp.Room && g.rnd(100) < prob {
-			claimed := false
-			for _, other := range g.Level.Monsters {
-				if other.Dest == &obj.Pos {
-					claimed = true
-					break
-				}
-			}
-			if !claimed {
-				return &obj.Pos
-			}
+
+		if g.roomIn(obj.Pos) == tp.Room && g.rnd(100) < prob &&
+			!g.objectClaimed(obj) {
+			return &obj.Pos
 		}
 	}
+
 	return &g.Player.Pos
 }
+
+// objectClaimed reports whether some monster already runs toward this
+// object (chase.c find_dest).
+func (g *RogueGame) objectClaimed(obj *Object) bool {
+	for _, other := range g.Level.Monsters {
+		if other.Dest == &obj.Pos {
+			return true
+		}
+	}
+
+	return false
+}

game/creature.go

@@ -23,6 +23,7 @@ type Monster struct {
 // in the C sources (cur_armor, purse, food_left, ...).
 type Player struct {
 	Creature
+
 	CurArmor    *Object    // what he is wearing
 	CurWeapon   *Object    // which weapon he is wielding
 	CurRing     [2]*Object // which rings are being worn (Left/Right)
@@ -40,15 +41,56 @@ type Player struct {
 func (c *Creature) On(f CreatureFlags) bool { return c.Flags.Has(f) }
 
 // IsRing is the C ISRING(hand, ring) macro.
-func (p *Player) IsRing(hand, ring int) bool {
-	return p.CurRing[hand] != nil && p.CurRing[hand].Which == ring
+func (p *Player) IsRing(hand int, ring RingKind) bool {
+	return p.CurRing[hand] != nil && p.CurRing[hand].RingKind() == ring
 }
 
 // IsWearing is the C ISWEARING(ring) macro: is the ring on either hand.
-func (p *Player) IsWearing(ring int) bool {
+func (p *Player) IsWearing(ring RingKind) bool {
 	return p.IsRing(Left, ring) || p.IsRing(Right, ring)
 }
 
+// nextPackChar claims and returns the next unused pack character (pack.c
+// pack_char).
+func (p *Player) nextPackChar() byte {
+	for i := range p.PackUsed {
+		if !p.PackUsed[i] {
+			p.PackUsed[i] = true
+
+			return byte(i) + 'a'
+		}
+	}
+
+	return byte(len(p.PackUsed)) + 'a' // C would walk off the array here
+}
+
+// removeFromPack takes an item out of the pack: the whole entry, or one
+// of a stack when all is false (the bookkeeping half of pack.c
+// leave_pack). It returns the object that left the pack — a copy when
+// newobj asks for a split.
+func (p *Player) removeFromPack(obj *Object, newobj, all bool) *Object {
+	p.Inpack--
+
+	nobj := obj
+	if obj.Count > 1 && !all {
+		obj.Count--
+		if obj.Group != 0 {
+			p.Inpack++
+		}
+
+		if newobj {
+			copied := *obj
+			nobj = &copied
+			nobj.Count = 1
+		}
+	} else {
+		p.PackUsed[obj.PackCh-'a'] = false
+		detachObj(&p.Pack, obj)
+	}
+
+	return nobj
+}
+
 // attachMon pushes a monster onto the front of a list (list.c attach).
 func attachMon(list *[]*Monster, item *Monster) {
 	*list = append([]*Monster{item}, *list...)
@@ -59,6 +101,7 @@ func detachMon(list *[]*Monster, item *Monster) {
 	for i, m := range *list {
 		if m == item {
 			*list = append((*list)[:i], (*list)[i+1:]...)
+
 			return
 		}
 	}

game/daemon.go

@@ -10,6 +10,10 @@ package game
 // function-pointer-to-int mapping in state.c rs_write_daemons.
 type DaemonID int
 
+// Daemon and fuse callback identifiers. The first block's numeric values
+// match the function-pointer-to-int mapping in state.c rs_write_daemons;
+// the second block covers fuses state.c never saved (the Go save format
+// handles them all uniformly).
 const (
 	DNone      DaemonID = 0
 	DRollwand  DaemonID = 1
@@ -21,12 +25,10 @@ const (
 	DUnconfuse DaemonID = 7
 	DUnsee     DaemonID = 8
 	DSight     DaemonID = 9
-	// Fuses beyond the C save map (state.c never saved these; the Go save
-	// format handles them uniformly).
-	DVisuals  DaemonID = 10
-	DComeDown DaemonID = 11
-	DLand     DaemonID = 12
-	DTurnSee  DaemonID = 13 // potions.c casts turn_see to a fuse callback
+	DVisuals   DaemonID = 10
+	DComeDown  DaemonID = 11
+	DLand      DaemonID = 12
+	DTurnSee   DaemonID = 13 // potions.c casts turn_see to a fuse callback
 )
 
 // Scheduling phases and slot states (daemon.c).
@@ -59,6 +61,7 @@ func (g *RogueGame) dSlot() *delayedAction {
 			return &g.Daemons.List[i]
 		}
 	}
+
 	panic("ran out of fuse slots") // C: debug message in MASTER, NULL deref otherwise
 }
 
@@ -70,6 +73,7 @@ func (g *RogueGame) findSlot(f DaemonID) *delayedAction {
 			return d
 		}
 	}
+
 	return nil
 }
 

game/daemons.go

@@ -5,38 +5,14 @@ package game
 
 // runDaemon invokes the callback named by id (the call through d_func in C).
 func (g *RogueGame) runDaemon(id DaemonID, arg int) {
-	switch id {
-	case DRollwand:
-		g.rollwand(arg)
-	case DDoctor:
-		g.doctor(arg)
-	case DStomach:
-		g.stomach(arg)
-	case DRunners:
-		g.runners(arg)
-	case DSwander:
-		g.swander(arg)
-	case DNohaste:
-		g.nohaste(arg)
-	case DUnconfuse:
-		g.unconfuse(arg)
-	case DUnsee:
-		g.unsee(arg)
-	case DSight:
-		g.sight(arg)
-	case DVisuals:
-		g.visuals(arg)
-	case DComeDown:
-		g.comeDown(arg)
-	case DLand:
-		g.land(arg)
-	case DTurnSee:
-		g.turnSee(arg != 0)
-	default:
-		// Callbacks are added to this switch as their subsystems are
-		// ported; reaching one that isn't here is a porting bug.
+	h := g.data.daemonHandlers[id]
+	if h == nil {
+		// Handlers are added to the table as their subsystems are
+		// ported; reaching one that isn't there is a porting bug.
 		panic("daemon not yet ported")
 	}
+
+	h(g, arg)
 }
 
 // doctor is the healing daemon that restores hit points after rest
@@ -45,6 +21,7 @@ func (g *RogueGame) doctor(int) {
 	p := &g.Player
 	lv := p.Stats.Lvl
 	ohp := p.Stats.HP
+
 	g.Quiet++
 	if lv < 8 {
 		if g.Quiet+(lv<<1) > 20 {
@@ -53,16 +30,20 @@ func (g *RogueGame) doctor(int) {
 	} else if g.Quiet >= 3 {
 		p.Stats.HP += g.rnd(lv-7) + 1
 	}
-	if p.IsRing(Left, RRegen) {
+
+	if p.IsRing(Left, RingRegeneration) {
 		p.Stats.HP++
 	}
-	if p.IsRing(Right, RRegen) {
+
+	if p.IsRing(Right, RingRegeneration) {
 		p.Stats.HP++
 	}
+
 	if ohp != p.Stats.HP {
 		if p.Stats.HP > p.Stats.MaxHP {
 			p.Stats.HP = p.Stats.MaxHP
 		}
+
 		g.Quiet = 0
 	}
 }
@@ -82,6 +63,7 @@ func (g *RogueGame) rollwand(int) {
 			g.KillDaemon(DRollwand)
 			g.Fuse(DSwander, 0, wanderTime(g), Before)
 		}
+
 		g.Daemons.Between = 0
 	}
 }
@@ -92,29 +74,32 @@ func wanderTime(g *RogueGame) int { return g.spread(70) }
 // unconfuse releases the poor player from his confusion (daemons.c
 // unconfuse).
 func (g *RogueGame) unconfuse(int) {
-	g.Player.Flags.Clear(IsHuh)
+	g.Player.Flags.Clear(Confused)
 	g.msg("you feel less %s now", g.chooseStr("trippy", "confused"))
 }
 
 // unsee turns off the ability to see invisible (daemons.c unsee).
 func (g *RogueGame) unsee(int) {
 	for _, th := range g.Level.Monsters {
-		if th.On(IsInvis) && g.seeMonst(th) {
+		if th.On(Invisible) && g.seeMonst(th) {
 			g.mvaddch(th.Pos.Y, th.Pos.X, th.OldCh)
 		}
 	}
-	g.Player.Flags.Clear(CanSee)
+
+	g.Player.Flags.Clear(CanSeeInvisible)
 }
 
 // sight gives the hero his sight back (daemons.c sight).
 func (g *RogueGame) sight(int) {
 	p := &g.Player
-	if p.On(IsBlind) {
+	if p.On(Blind) {
 		g.Extinguish(DSight)
-		p.Flags.Clear(IsBlind)
-		if !p.Room.Flags.Has(IsGone) {
+		p.Flags.Clear(Blind)
+
+		if !p.Room.Flags.Has(Gone) {
 			g.enterRoom(p.Pos)
 		}
+
 		g.msg("%s", g.chooseStr("far out!  Everything is all cosmic again",
 			"the veil of darkness lifts"))
 	}
@@ -122,88 +107,114 @@ func (g *RogueGame) sight(int) {
 
 // nohaste ends the hasting (daemons.c nohaste).
 func (g *RogueGame) nohaste(int) {
-	g.Player.Flags.Clear(IsHaste)
+	g.Player.Flags.Clear(Hasted)
 	g.msg("you feel yourself slowing down")
 }
 
 // stomach digests the hero's food (daemons.c stomach).
 func (g *RogueGame) stomach(int) {
 	p := &g.Player
+
 	origHungry := p.HungryState
 	if p.FoodLeft <= 0 {
-		if p.FoodLeft--; p.FoodLeft < -StarveTime {
-			g.death('s')
-		}
-		// the hero is fainting
-		if g.NoCommand != 0 || g.rnd(5) != 0 {
-			return
-		}
-		g.NoCommand += g.rnd(8) + 4
-		p.HungryState = 3
-		if !g.Options.Terse {
-			g.addmsg("%s", g.chooseStr(
-				"the munchies overpower your motor capabilities.  ",
-				"you feel too weak from lack of food.  "))
-		}
-		g.msg("%s", g.chooseStr("You freak out", "You faint"))
+		g.stomachFaint()
 	} else {
-		oldfood := p.FoodLeft
-		amulet := 0
-		if g.HasAmulet {
-			amulet = 1
-		}
-		p.FoodLeft -= g.ringEat(Left) + g.ringEat(Right) + 1 - amulet
-
-		if p.FoodLeft < MoreTime && oldfood >= MoreTime {
-			p.HungryState = 2
-			g.msg("%s", g.chooseStr(
-				"the munchies are interfering with your motor capabilites",
-				"you are starting to feel weak"))
-		} else if p.FoodLeft < 2*MoreTime && oldfood >= 2*MoreTime {
-			p.HungryState = 1
-			if g.Options.Terse {
-				g.msg("%s", g.chooseStr("getting the munchies", "getting hungry"))
-			} else {
-				g.msg("%s", g.chooseStr("you are getting the munchies",
-					"you are starting to get hungry"))
-			}
-		}
+		g.stomachDigest()
 	}
+
 	if p.HungryState != origHungry {
-		p.Flags.Clear(IsRun)
+		p.Flags.Clear(Awake)
+
 		g.Running = false
 		g.ToDeath = false
 		g.Count = 0
 	}
 }
 
+// stomachFaint starves and possibly faints an empty-stomached hero (the
+// no-food arm of daemons.c stomach).
+func (g *RogueGame) stomachFaint() {
+	p := &g.Player
+	if p.FoodLeft--; p.FoodLeft < -StarveTime {
+		g.death('s')
+	}
+	// the hero is fainting
+	if g.NoCommand != 0 || g.rnd(5) != 0 {
+		return
+	}
+
+	g.NoCommand += g.rnd(8) + 4
+	p.HungryState = 3
+
+	if !g.Options.Terse {
+		g.addmsgf("%s", g.chooseStr(
+			"the munchies overpower your motor capabilities.  ",
+			"you feel too weak from lack of food.  "))
+	}
+
+	g.msg("%s", g.chooseStr("You freak out", "You faint"))
+}
+
+// stomachDigest burns food and reports growing hunger (the fed arm of
+// daemons.c stomach).
+func (g *RogueGame) stomachDigest() {
+	p := &g.Player
+	oldfood := p.FoodLeft
+
+	amulet := 0
+	if g.HasAmulet {
+		amulet = 1
+	}
+
+	p.FoodLeft -= g.ringEat(Left) + g.ringEat(Right) + 1 - amulet
+
+	if p.FoodLeft < MoreTime && oldfood >= MoreTime {
+		p.HungryState = 2
+
+		g.msg("%s", g.chooseStr(
+			"the munchies are interfering with your motor capabilities",
+			"you are starting to feel weak"))
+	} else if p.FoodLeft < 2*MoreTime && oldfood >= 2*MoreTime {
+		p.HungryState = 1
+
+		if g.Options.Terse {
+			g.msg("%s", g.chooseStr("getting the munchies", "getting hungry"))
+		} else {
+			g.msg("%s", g.chooseStr("you are getting the munchies",
+				"you are starting to get hungry"))
+		}
+	}
+}
+
 // comeDown takes the hero down off her acid trip (daemons.c come_down).
 func (g *RogueGame) comeDown(int) {
 	p := &g.Player
-	if !p.On(IsHalu) {
+	if !p.On(Hallucinating) {
 		return
 	}
 
 	g.KillDaemon(DVisuals)
-	p.Flags.Clear(IsHalu)
+	p.Flags.Clear(Hallucinating)
 
-	if p.On(IsBlind) {
+	if p.On(Blind) {
 		return
 	}
 
 	// undo the things
 	for _, tp := range g.Level.Objects {
-		if g.cansee(tp.Pos.Y, tp.Pos.X) {
-			g.mvaddch(tp.Pos.Y, tp.Pos.X, tp.Type)
+		if g.canSee(tp.Pos.Y, tp.Pos.X) {
+			g.mvaddch(tp.Pos.Y, tp.Pos.X, tp.Kind.Glyph())
 		}
 	}
 
 	// undo the monsters
-	seemonst := p.On(SeeMonst)
+	seemonst := p.On(SenseMonsters)
+
 	for _, tp := range g.Level.Monsters {
 		g.move(tp.Pos.Y, tp.Pos.X)
-		if g.cansee(tp.Pos.Y, tp.Pos.X) {
-			if !tp.On(IsInvis) || p.On(CanSee) {
+
+		if g.canSee(tp.Pos.Y, tp.Pos.X) {
+			if !tp.On(Invisible) || p.On(CanSeeInvisible) {
 				g.addch(tp.Disguise)
 			} else {
 				g.addch(g.Level.Char(tp.Pos.Y, tp.Pos.X))
@@ -214,41 +225,49 @@ func (g *RogueGame) comeDown(int) {
 			g.standend()
 		}
 	}
+
 	g.msg("Everything looks SO boring now.")
 }
 
 // visuals changes the characters for the player while hallucinating
 // (daemons.c visuals).
 func (g *RogueGame) visuals(int) {
-	p := &g.Player
 	if !g.After || (g.Running && g.Options.Jump) {
 		return
 	}
 	// change the things
 	for _, tp := range g.Level.Objects {
-		if g.cansee(tp.Pos.Y, tp.Pos.X) {
+		if g.canSee(tp.Pos.Y, tp.Pos.X) {
 			g.mvaddch(tp.Pos.Y, tp.Pos.X, g.rndThing())
 		}
 	}
 
 	// change the stairs
-	if !g.SeenStairs && g.cansee(g.Level.Stairs.Y, g.Level.Stairs.X) {
+	if !g.SeenStairs && g.canSee(g.Level.Stairs.Y, g.Level.Stairs.X) {
 		g.mvaddch(g.Level.Stairs.Y, g.Level.Stairs.X, g.rndThing())
 	}
 
 	// change the monsters
-	seemonst := p.On(SeeMonst)
+	g.visualMonsters()
+}
+
+// visualMonsters redraws the monsters through the hallucination (the
+// monster loop of daemons.c visuals).
+func (g *RogueGame) visualMonsters() {
+	seemonst := g.Player.On(SenseMonsters)
+
 	for _, tp := range g.Level.Monsters {
 		g.move(tp.Pos.Y, tp.Pos.X)
+
 		if g.seeMonst(tp) {
 			if tp.Type == 'X' && tp.Disguise != 'X' {
 				g.addch(g.rndThing())
 			} else {
-				g.addch(byte(g.rnd(26) + 'A'))
+				g.addch(g.randomMonsterLetter())
 			}
 		} else if seemonst {
 			g.standout()
-			g.addch(byte(g.rnd(26) + 'A'))
+			g.addch(g.randomMonsterLetter())
 			g.standend()
 		}
 	}
@@ -256,7 +275,7 @@ func (g *RogueGame) visuals(int) {
 
 // land lands the hero from a levitation potion (daemons.c land).
 func (g *RogueGame) land(int) {
-	g.Player.Flags.Clear(IsLevit)
+	g.Player.Flags.Clear(Levitating)
 	g.msg("%s", g.chooseStr("bummer!  You've hit the ground",
 		"you float gently to the ground"))
 }

game/dice.go

@@ -0,0 +1,67 @@
+package game
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Rogue expresses damage as strings like "1x4/3x6": one attack rolling
+// 1d4 and a second rolling 3d6. The C code re-parsed these with atoi on
+// every swing (fight.c roll_em); the port parses them once, at table
+// definition or item creation, into a DiceSpec.
+
+// DiceRoll is one attack's dice: Count rolls of a Sides-sided die.
+type DiceRoll struct {
+	Count int
+	Sides int
+}
+
+// DiceSpec is the sequence of attacks a damage string described.
+type DiceSpec []DiceRoll
+
+// ParseDice parses a C damage string with the exact semantics of the
+// roll_em loop: leading digits (C atoi) before and after each 'x', attacks
+// separated by '/'. Junk like the bestiary's "%%%x0" placeholder parses as
+// a single 0x0 attack, as it did in C.
+func ParseDice(s string) DiceSpec {
+	var spec DiceSpec
+
+	for s != "" {
+		count := cAtoi(s)
+
+		xi := strings.IndexByte(s, 'x')
+		if xi < 0 {
+			break
+		}
+
+		s = s[xi+1:]
+		spec = append(spec, DiceRoll{Count: count, Sides: cAtoi(s)})
+
+		si := strings.IndexByte(s, '/')
+		if si < 0 {
+			break
+		}
+
+		s = s[si+1:]
+	}
+
+	return spec
+}
+
+// dice is the table-definition shorthand for ParseDice.
+func dice(s string) DiceSpec { return ParseDice(s) }
+
+// String renders the spec back in the classic "NxM/NxM" form.
+func (d DiceSpec) String() string {
+	var sb strings.Builder
+
+	for i, r := range d {
+		if i > 0 {
+			sb.WriteByte('/')
+		}
+
+		fmt.Fprintf(&sb, "%dx%d", r.Count, r.Sides)
+	}
+
+	return sb.String()
+}

game/dice_test.go

@@ -0,0 +1,47 @@
+package game
+
+import "testing"
+
+// ParseDice must keep the exact semantics of the C roll_em parse loop,
+// including its junk-tolerant edges: the bestiary placeholder "%%%x0" and
+// the flytrap reset "000x0" both mean a single 0x0 attack.
+func TestParseDice(t *testing.T) {
+	cases := []struct {
+		in   string
+		want string
+		len  int
+	}{
+		{"1x4", "1x4", 1},
+		{"1x2/1x5/1x5", "1x2/1x5/1x5", 3},
+		{"2x12/2x4", "2x12/2x4", 2},
+		{"0x0", "0x0", 1},
+		{"000x0", "0x0", 1},
+		{"%%%x0", "0x0", 1},
+		{"", "", 0},
+		{"3", "", 0}, // no 'x': C parses nothing
+	}
+	for _, c := range cases {
+		got := ParseDice(c.in)
+		if len(got) != c.len || got.String() != c.want {
+			t.Errorf("ParseDice(%q) = %v (len %d), want %q (len %d)",
+				c.in, got, len(got), c.want, c.len)
+		}
+	}
+}
+
+// The bestiary and weapon tables must parse to at least one attack each so
+// every creature and weapon actually swings.
+func TestTablesHaveDice(t *testing.T) {
+	data := newGameData()
+	for i, m := range data.monsterTable {
+		if len(m.Stats.Dmg) == 0 {
+			t.Errorf("monster %c (%s) has no attacks", 'A'+i, m.Name)
+		}
+	}
+
+	for w, iw := range data.initWeaps {
+		if len(iw.dam) == 0 || len(iw.hrl) == 0 {
+			t.Errorf("weapon %d has empty dice", w)
+		}
+	}
+}

game/effects_test.go

@@ -2,13 +2,16 @@ package game
 
 import "testing"
 
-// mkGameInput builds a headless game whose input plays the given script.
-func mkGameInput(t *testing.T, seed int32, input string) *RogueGame {
+// mkGameInput builds a headless game; tests script it via setInput. The
+// fixed seed keeps the scripted item/monster interactions stable.
+func mkGameInput(t *testing.T) *RogueGame {
 	t.Helper()
-	g := NewGame(Config{Seed: seed, Term: &testTerm{input: []byte(input)}})
+
+	g := New(Params{Seed: 5, Term: &testTerm{}})
 	g.NewLevel()
 	g.Oldpos = g.Player.Pos
-	g.Oldrp = g.roomin(g.Player.Pos)
+	g.Oldrp = g.roomIn(g.Player.Pos)
+
 	return g
 }
 
@@ -16,42 +19,61 @@ func mkGameInput(t *testing.T, seed int32, input string) *RogueGame {
 func give(g *RogueGame, obj *Object) byte {
 	obj.Count = 1
 	g.addPack(obj, true)
+
 	return obj.PackCh
 }
 
+// setInput replaces the scripted terminal input.
+func setInput(t *testing.T, g *RogueGame, input ...byte) {
+	t.Helper()
+
+	tt, ok := g.scr.term.(*testTerm)
+	if !ok {
+		t.Fatal("game terminal is not a testTerm")
+	}
+
+	tt.input = input
+	tt.pos = 0
+}
+
 func TestQuaffHealingPotion(t *testing.T) {
-	g := mkGameInput(t, 5, "")
+	g := mkGameInput(t)
 	pot := newObject()
-	pot.Type = Potion
-	pot.Which = PHealing
+	pot.Kind = KindPotion
+	pot.Which = int(PotionHealing)
 	ch := give(g, pot)
-	g.scr.term.(*testTerm).input = []byte{ch}
+	setInput(t, g, ch)
 
 	g.Player.Stats.HP = 1
 	g.quaff()
+
 	if g.Player.Stats.HP <= 1 {
 		t.Error("healing potion did not heal")
 	}
-	if !g.Items.Potions[PHealing].Know {
+
+	if !g.Items.Potions[PotionHealing].Know {
 		t.Error("healing potion not identified after drinking")
 	}
+
 	if len(g.Player.Pack) != 5 {
 		t.Errorf("potion not consumed: %d items", len(g.Player.Pack))
 	}
 }
 
 func TestQuaffConfusionSetsFlagAndFuse(t *testing.T) {
-	g := mkGameInput(t, 5, "")
+	g := mkGameInput(t)
 	pot := newObject()
-	pot.Type = Potion
-	pot.Which = PConfuse
+	pot.Kind = KindPotion
+	pot.Which = int(PotionConfusion)
 	ch := give(g, pot)
-	g.scr.term.(*testTerm).input = []byte{ch}
+	setInput(t, g, ch)
 
 	g.quaff()
-	if !g.Player.On(IsHuh) {
+
+	if !g.Player.On(Confused) {
 		t.Error("confusion potion did not confuse")
 	}
+
 	if g.findSlot(DUnconfuse) == nil {
 		t.Error("no unconfuse fuse pending")
 	}
@@ -59,24 +81,26 @@ func TestQuaffConfusionSetsFlagAndFuse(t *testing.T) {
 	for range 30 {
 		g.DoFuses(After)
 	}
-	if g.Player.On(IsHuh) {
+
+	if g.Player.On(Confused) {
 		t.Error("confusion never wore off")
 	}
 }
 
 func TestReadEnchantArmor(t *testing.T) {
-	g := mkGameInput(t, 5, "")
+	g := mkGameInput(t)
 	scr := newObject()
-	scr.Type = Scroll
-	scr.Which = SArmor
+	scr.Kind = KindScroll
+	scr.Which = int(ScrollEnchantArmor)
 	ch := give(g, scr)
-	g.scr.term.(*testTerm).input = []byte{ch}
+	setInput(t, g, ch)
 
-	before := g.Player.CurArmor.Arm
+	before := g.Player.CurArmor.ArmorClass
 	g.readScroll()
-	if g.Player.CurArmor.Arm != before-1 {
+
+	if g.Player.CurArmor.ArmorClass != before-1 {
 		t.Errorf("enchant armor: AC %d -> %d, want %d",
-			before, g.Player.CurArmor.Arm, before-1)
+			before, g.Player.CurArmor.ArmorClass, before-1)
 	}
 }
 
@@ -86,18 +110,20 @@ func TestReadHoldMonsterFreezesAdjacent(t *testing.T) {
 	// look(TRUE) at the end of read_scroll immediately re-wakes greedy
 	// monsters. The port reproduces that quirk faithfully — see
 	// TestHoldScrollGreedyMonsterQuirk.
-	g := mkGameInput(t, 5, "")
+	g := mkGameInput(t)
 	tp := spawnAdjacent(g, 'Z')
-	tp.Flags.Set(IsRun)
+	tp.Flags.Set(Awake)
+
 	scr := newObject()
-	scr.Type = Scroll
-	scr.Which = SHold
+	scr.Kind = KindScroll
+	scr.Which = int(ScrollHoldMonster)
 	ch := give(g, scr)
-	g.scr.term.(*testTerm).input = []byte{ch}
+	setInput(t, g, ch)
 
 	g.readScroll()
 	t.Logf("after scroll: flags=%o huh=%q", tp.Flags, g.Msgs.Huh)
-	if tp.On(IsRun) || !tp.On(IsHeld) {
+
+	if tp.On(Awake) || !tp.On(Held) {
 		t.Error("hold monster scroll did not hold the adjacent monster")
 	}
 }
@@ -107,63 +133,75 @@ func TestReadHoldMonsterFreezesAdjacent(t *testing.T) {
 // (orc) held by a scroll is re-woken by the look(TRUE) that read_scroll
 // performs, ending up both held and running again.
 func TestHoldScrollGreedyMonsterQuirk(t *testing.T) {
-	g := mkGameInput(t, 5, "")
+	g := mkGameInput(t)
 	tp := spawnAdjacent(g, 'O')
-	tp.Flags.Set(IsRun)
+	tp.Flags.Set(Awake)
+
 	scr := newObject()
-	scr.Type = Scroll
-	scr.Which = SHold
+	scr.Kind = KindScroll
+	scr.Which = int(ScrollHoldMonster)
 	ch := give(g, scr)
-	g.scr.term.(*testTerm).input = []byte{ch}
+	setInput(t, g, ch)
 
 	g.readScroll()
-	t.Logf("orc after scroll: flags=%o (IsRun=%v IsHeld=%v)",
-		tp.Flags, tp.On(IsRun), tp.On(IsHeld))
-	if !tp.On(IsHeld) {
-		t.Error("orc lost IsHeld entirely")
+	t.Logf("orc after scroll: flags=%o (Awake=%v Held=%v)",
+		tp.Flags, tp.On(Awake), tp.On(Held))
+
+	if !tp.On(Held) {
+		t.Error("orc lost Held entirely")
 	}
-	if !tp.On(IsRun) {
+
+	if !tp.On(Awake) {
 		t.Error("quirk changed: greedy monster stayed held; if this is a " +
 			"deliberate fix, update this test and ARCHITECTURE.md")
 	}
 }
 
 func TestZapSlowMonster(t *testing.T) {
-	g := mkGameInput(t, 5, "")
+	g := mkGameInput(t)
 	tp := spawnAdjacent(g, 'Z')
 	stick := newObject()
-	stick.Type = Stick
-	stick.Which = WsSlowM
+	stick.Kind = KindWand
+	stick.Which = int(WandSlowMonster)
 	g.fixStick(stick)
 	ch := give(g, stick)
-	g.scr.term.(*testTerm).input = []byte{ch}
+	setInput(t, g, ch)
+
 	g.Delta = Coord{X: 1, Y: 0} // aim at the monster
 
-	charges := stick.Charges()
+	charges := stick.Charges
+
 	g.doZap()
-	if !tp.On(IsSlow) {
+
+	if !tp.On(Slowed) {
 		t.Error("slow monster wand did not slow")
 	}
-	if stick.Charges() != charges-1 {
+
+	if stick.Charges != charges-1 {
 		t.Error("zap did not use a charge")
 	}
 }
 
 func TestParseOpts(t *testing.T) {
-	g := NewGame(Config{Seed: 1})
+	g := New(Params{Seed: 1})
 	g.ParseOpts("terse,nojump,name=Conan,fruit=mango,inven=slow")
+
 	if !g.Options.Terse {
 		t.Error("terse not set")
 	}
+
 	if g.Options.Jump {
 		t.Error("nojump not honored")
 	}
+
 	if g.Whoami != "Conan" {
 		t.Errorf("name = %q", g.Whoami)
 	}
+
 	if g.Fruit != "mango" {
 		t.Errorf("fruit = %q", g.Fruit)
 	}
+
 	if g.Options.InvType != InvSlow {
 		t.Errorf("inven = %d", g.Options.InvType)
 	}

game/fight_test.go

@@ -6,10 +6,12 @@ import "testing"
 // look() state the way playit() does before the first command.
 func mkGame(t *testing.T, seed int32) *RogueGame {
 	t.Helper()
-	g := NewGame(Config{Seed: seed, Term: &testTerm{}})
+
+	g := New(Params{Seed: seed, Term: &testTerm{}})
 	g.NewLevel()
 	g.Oldpos = g.Player.Pos
-	g.Oldrp = g.roomin(g.Player.Pos)
+	g.Oldrp = g.roomIn(g.Player.Pos)
+
 	return g
 }
 
@@ -18,20 +20,22 @@ func spawnAdjacent(g *RogueGame, typ byte) *Monster {
 	pos := Coord{X: g.Player.Pos.X + 1, Y: g.Player.Pos.Y}
 	tp := &Monster{}
 	g.newMonster(tp, typ, pos)
+
 	return tp
 }
 
 func TestRollEmParsesMultiAttackDice(t *testing.T) {
 	g := mkGame(t, 42)
-	att := &Creature{Stats: Stats{Str: 16, Lvl: 20, Dmg: "1x4/1x4/1x4"}}
-	def := &Creature{Stats: Stats{Arm: 10, HP: 1000}}
-	def.Flags.Set(IsRun)
+	att := &Creature{Stats: Stats{Str: 16, Lvl: 20, Dmg: dice("1x4/1x4/1x4")}}
+	def := &Creature{Stats: Stats{ArmorClass: 10, HP: 1000}}
+	def.Flags.Set(Awake)
 	// With attacker level 20 vs armor 10, swing always hits
 	// (rnd(20)+wplus >= (20-20)-10 is always true), so three attacks of
 	// 1x4 + str bonus 1 each must deal between 6 and 15 damage.
-	if !g.rollEm(att, def, nil, false) {
+	if !g.rollAttacks(att, def, nil, false) {
 		t.Fatal("attack with guaranteed swing missed")
 	}
+
 	dmg := 1000 - def.Stats.HP
 	if dmg < 6 || dmg > 15 {
 		t.Errorf("three 1x4+1 attacks dealt %d damage, want 6..15", dmg)
@@ -45,12 +49,15 @@ func TestFightKillsMonster(t *testing.T) {
 	g.Player.Stats.Lvl = 20 // always hits
 	before := len(g.Level.Monsters)
 	g.fight(tp.Pos, g.Player.CurWeapon, false)
+
 	if len(g.Level.Monsters) != before-1 {
 		t.Error("monster not removed after fatal fight")
 	}
+
 	if g.Level.MonsterAt(tp.Pos.Y, tp.Pos.X) != nil {
 		t.Error("map still records dead monster")
 	}
+
 	if g.Player.Stats.Exp == 0 {
 		t.Error("no experience for the kill")
 	}
@@ -60,46 +67,37 @@ func TestAttackHurtsPlayer(t *testing.T) {
 	g := mkGame(t, 9)
 	tp := spawnAdjacent(g, 'T') // troll: 1x8/1x8/2x6
 	tp.Stats.Lvl = 20           // always hits
-	tp.Flags.Clear(IsCanc)
+	tp.Flags.Clear(Cancelled)
+
 	hpBefore := g.Player.Stats.HP
 	g.Player.Stats.HP = 500
 	g.Player.Stats.MaxHP = 500
 	g.attack(tp)
+
 	if g.Player.Stats.HP >= 500 {
 		t.Errorf("player HP unchanged (%d -> %d)", hpBefore, g.Player.Stats.HP)
 	}
 }
 
-func TestDeathUnwindsWithGameEnd(t *testing.T) {
-	g := mkGame(t, 11)
-	defer func() {
-		r := recover()
-		if _, ok := r.(gameEnd); !ok {
-			t.Fatalf("death did not unwind with gameEnd, got %v", r)
-		}
-		if g.Playing {
-			t.Error("still playing after death")
-		}
-	}()
-	g.Options.Tombstone = false
-	g.death('K')
-}
-
 func TestRunnersChaseHero(t *testing.T) {
 	g := mkGame(t, 3)
 	// Place a hobgoblin a few squares away in the hero's room and set it
 	// running at the hero.
 	p := &g.Player
+
 	pos := Coord{X: p.Pos.X + 3, Y: p.Pos.Y}
 	if !stepOk(g.Level.Char(pos.Y, pos.X)) || g.Level.MonsterAt(pos.Y, pos.X) != nil {
 		t.Skip("no clear lane on this seed")
 	}
+
 	tp := &Monster{}
 	g.newMonster(tp, 'H', pos)
-	tp.Flags.Set(IsRun)
+	tp.Flags.Set(Awake)
 	tp.Dest = &p.Pos
 	d0 := distCp(tp.Pos, p.Pos)
+
 	g.runners(0)
+
 	if d1 := distCp(tp.Pos, p.Pos); d1 >= d0 {
 		t.Errorf("monster did not close distance: %d -> %d", d0, d1)
 	}

game/game.go

@@ -3,19 +3,19 @@ package game
 // ItemLore is the per-game item identity state: the randomized appearance
 // names and the seven mutable ObjInfo tables (extern.c/init.c).
 type ItemLore struct {
-	PotColors  [MaxPotions]string // p_colors: colors of the potions
-	ScrNames   [MaxScrolls]string // s_names: names of the scrolls
-	RingStones [MaxRings]string   // r_stones: stone settings of the rings
-	WandMade   [MaxSticks]string  // ws_made: what sticks are made of
-	WandType   [MaxSticks]string  // ws_type: "wand" or "staff"
+	PotColors  [NumPotionTypes]string // p_colors: colors of the potions
+	ScrNames   [NumScrollTypes]string // s_names: names of the scrolls
+	RingStones [NumRingTypes]string   // r_stones: stone settings of the rings
+	WandMade   [NumWandTypes]string   // ws_made: what sticks are made of
+	WandType   [NumWandTypes]string   // ws_type: "wand" or "staff"
 
 	Things  [NumThings]ObjInfo
-	Potions [MaxPotions]ObjInfo
-	Scrolls [MaxScrolls]ObjInfo
-	Rings   [MaxRings]ObjInfo
-	Sticks  [MaxSticks]ObjInfo
-	Weapons [MaxWeapons + 1]ObjInfo
-	Armors  [MaxArmors]ObjInfo
+	Potions [NumPotionTypes]ObjInfo
+	Scrolls [NumScrollTypes]ObjInfo
+	Rings   [NumRingTypes]ObjInfo
+	Sticks  [NumWandTypes]ObjInfo
+	Weapons [NumWeaponTypes + 1]ObjInfo
+	Armors  [NumArmorTypes]ObjInfo
 
 	Group int // group number for the next stack of missiles (weapons.c `group`)
 }
@@ -31,9 +31,9 @@ type Options struct {
 	InvType    int  // inven: inventory style (InvOver/InvSlow/InvClear)
 }
 
-// Config carries everything needed to construct a game.
-type Config struct {
-	Seed      int32    // dungeon number; the caller derives it (time+pid or SEED env)
+// Params carries everything needed to construct a game.
+type Params struct {
+	Seed      int32    // dungeon number; caller derives it (time+pid or SEED)
 	Name      string   // player name (overridden by ROGUEOPTS name=)
 	RogueOpts string   // the ROGUEOPTS environment string
 	Home      string   // home directory (save file default location)
@@ -44,7 +44,7 @@ type Config struct {
 
 // RogueGame is one complete game of Rogue: every piece of state that was a
 // global (or file-scope static) in the C sources, plus the terminal it is
-// played on. Construct with NewGame, then call Run.
+// played on. Construct with New, then call Run.
 //
 // The struct grows with the port; fields appear in the phase that ports the
 // code owning them.
@@ -110,7 +110,7 @@ type RogueGame struct {
 
 	// screen / messages
 	scr         *Screen
-	Msgs        MsgLine
+	Msgs        MessageLine
 	statusCache statusCache
 	invPage     invPage // things.c discovery-list pagination statics
 
@@ -138,23 +138,27 @@ type RogueGame struct {
 
 	rogueOpts string // the ROGUEOPTS string, re-parsed by playit as in C
 	restored  bool   // game came from a save file; Run skips setup
+
+	// data is the game's copy of the static tables (extern.c and friends).
+	data *gameData
 }
 
-// NewGame builds a game from cfg, seeds the RNG, and randomizes the item
+// New builds a game from params, seeds the RNG, and randomizes the item
 // appearance tables (the front half of main.c main(); the player roll-up
 // and first level arrive with later porting phases).
-func NewGame(cfg Config) *RogueGame {
+func New(params Params) *RogueGame {
 	g := &RogueGame{
-		Rng:       &Rng{Seed: cfg.Seed},
-		Dnum:      int(cfg.Seed),
-		Whoami:    cfg.Name,
+		data:      newGameData(),
+		Rng:       &Rng{Seed: params.Seed},
+		Dnum:      int(params.Seed),
+		Whoami:    params.Name,
 		Fruit:     "slime-mold",
-		Home:      cfg.Home,
-		Wizard:    cfg.Wizard,
-		NoScore:   cfg.Wizard,
+		Home:      params.Home,
+		Wizard:    params.Wizard,
+		NoScore:   params.Wizard,
 		Playing:   true,
 		Depth:     1,
-		ScorePath: cfg.ScorePath,
+		ScorePath: params.ScorePath,
 		LastScore: -1,
 	}
 	g.Options = Options{
@@ -164,20 +168,24 @@ func NewGame(cfg Config) *RogueGame {
 	}
 	g.InvDescribe = true
 	g.Msgs.SaveMsg = true
-	g.scr = NewScreen(cfg.Term)
-	g.FileName = cfg.Home + "/rogue.save"
-	g.rogueOpts = cfg.RogueOpts
-	if cfg.Wizard {
-		g.Player.Flags.Set(SeeMonst)
-	}
-	if cfg.RogueOpts != "" {
-		g.ParseOpts(cfg.RogueOpts)
+	g.scr = NewScreen(params.Term)
+	g.Msgs.attach(g.scr, g.look, g.readchar)
+	g.FileName = params.Home + "/rogue.save"
+
+	g.rogueOpts = params.RogueOpts
+	if params.Wizard {
+		g.Player.Flags.Set(SenseMonsters)
 	}
 
-	g.Monsters = monsterTable
+	if params.RogueOpts != "" {
+		g.ParseOpts(params.RogueOpts)
+	}
+
+	g.Monsters = g.data.monsterTable
+
 	g.Items.Group = 2 // weapons.c: int group = 2
 	for i := range g.Level.Passages {
-		g.Level.Passages[i].Flags = IsGone | IsDark
+		g.Level.Passages[i].Flags = Gone | Dark
 	}
 
 	g.initProbs()     // set up prob tables for objects
@@ -186,34 +194,50 @@ func NewGame(cfg Config) *RogueGame {
 	g.initColors()    // set up colors of potions
 	g.initStones()    // set up stone settings of rings
 	g.initMaterials() // set up materials of wands
+
 	return g
 }
 
 // Run plays the game to its end: the back half of main.c main() plus
-// playit(). It returns after death, victory, quitting, or saving.
-func (g *RogueGame) Run() (err error) {
-	defer func() {
-		if r := recover(); r != nil {
-			if _, ok := r.(gameEnd); ok {
-				return // normal game over / save exit
-			}
-			panic(r)
-		}
-	}()
-	if !g.restored {
-		g.NewLevel() // draw current level
-		// Start up daemons and fuses
-		g.StartDaemon(DRunners, 0, After)
-		g.StartDaemon(DDoctor, 0, After)
-		g.Fuse(DSwander, 0, wanderTime(g), After)
-		g.StartDaemon(DStomach, 0, After)
-	}
+// playit(). It does not return — the game ends by exiting the process
+// (see myExit); one game run is one process.
+func (g *RogueGame) Run() {
+	g.startLevel()
 	g.playit()
-	return nil
+}
+
+// startLevel draws the first level and starts the standing daemons and
+// fuses for a fresh game; a restored game brings its own (the back half
+// of main.c main()).
+func (g *RogueGame) startLevel() {
+	if g.restored {
+		return
+	}
+
+	g.NewLevel() // draw current level
+	// Start up daemons and fuses
+	g.StartDaemon(DRunners, 0, After)
+	g.StartDaemon(DDoctor, 0, After)
+	g.Fuse(DSwander, 0, wanderTime(g), After)
+	g.StartDaemon(DStomach, 0, After)
 }
 
 // playit is the main loop of the program (main.c playit).
 func (g *RogueGame) playit() {
+	g.prePlay()
+
+	for g.Playing {
+		g.command() // command execution
+	}
+
+	g.endit()
+}
+
+// prePlay does the option and position setup at the top of playit,
+// before the command loop (main.c playit). It is split out so tests can
+// drive a bounded number of turns; the loop itself never returns,
+// because game-over exits the process.
+func (g *RogueGame) prePlay() {
 	// set up defaults for modern terminals: curses' md_hasclreol() is
 	// always true, so the C default inventory style applies
 	if !g.restored {
@@ -226,11 +250,7 @@ func (g *RogueGame) playit() {
 	}
 
 	g.Oldpos = g.Player.Pos
-	g.Oldrp = g.roomin(g.Player.Pos)
-	for g.Playing {
-		g.command() // command execution
-	}
-	g.endit()
+	g.Oldrp = g.roomIn(g.Player.Pos)
 }
 
 // endit exits the game (main.c endit).
@@ -242,7 +262,7 @@ func (g *RogueGame) endit() {
 func (g *RogueGame) fatal(s string) {
 	g.mvaddstr(NumLines-2, 0, s)
 	g.refresh()
-	g.myExit(0)
+	g.myExit()
 }
 
 // quit has the player make certain, then exits (main.c quit). The final
@@ -252,17 +272,21 @@ func (g *RogueGame) quit(int) {
 	if !g.QComm {
 		g.Msgs.Mpos = 0
 	}
+
 	oy, ox := g.scr.Std.GetYX()
 	g.msg("really quit?")
+
 	if g.readchar() == 'y' {
 		g.clear()
-		g.scr.Std.MvPrintw(NumLines-2, 0, "You quit with %d gold pieces", g.Player.Purse)
+		g.scr.Std.MvPrintwf(NumLines-2, 0, "You quit with %d gold pieces", g.Player.Purse)
 		g.move(NumLines-1, 0)
 		g.refresh()
 		g.score(g.Player.Purse, 1, 0)
-		g.myExit(0)
+		g.myExit()
+
 		return
 	}
+
 	g.move(0, 0)
 	g.clrtoeol()
 	g.status()

game/init.go

@@ -8,78 +8,84 @@ import "strings"
 // initPlayer rolls her up (init.c init_player).
 func (g *RogueGame) initPlayer() {
 	p := &g.Player
-	p.MaxStats = initStats
+	p.MaxStats = g.data.initStats
 	p.Stats = p.MaxStats
 	p.FoodLeft = HungerTime
 	// Give him some food
 	obj := newObject()
-	obj.Type = Food
+	obj.Kind = KindFood
 	obj.Count = 1
 	g.addPack(obj, true)
 	// And his suit of armor
 	obj = newObject()
-	obj.Type = Armor
-	obj.Which = RingMail
-	obj.Arm = aClass[RingMail] - 1
-	obj.Flags.Set(IsKnow)
+	obj.Kind = KindArmor
+	obj.Which = int(ArmorRingMail)
+	obj.ArmorClass = g.data.aClass[ArmorRingMail] - 1
+	obj.Flags.Set(Known)
 	obj.Count = 1
 	p.CurArmor = obj
 	g.addPack(obj, true)
 	// Give him his weaponry.  First a mace.
 	obj = newObject()
-	g.initWeapon(obj, Mace)
+	g.initWeapon(obj, WeaponMace)
 	obj.HPlus = 1
 	obj.DPlus = 1
-	obj.Flags.Set(IsKnow)
+	obj.Flags.Set(Known)
 	g.addPack(obj, true)
 	p.CurWeapon = obj
 	// Now a +1 bow
 	obj = newObject()
-	g.initWeapon(obj, Bow)
+	g.initWeapon(obj, WeaponBow)
 	obj.HPlus = 1
-	obj.Flags.Set(IsKnow)
+	obj.Flags.Set(Known)
 	g.addPack(obj, true)
 	// Now some arrows
 	obj = newObject()
-	g.initWeapon(obj, Arrow)
+	g.initWeapon(obj, WeaponArrow)
 	obj.Count = g.rnd(15) + 25
-	obj.Flags.Set(IsKnow)
+	obj.Flags.Set(Known)
 	g.addPack(obj, true)
 }
 
 // initColors initializes the potion color scheme for this game
 // (init.c init_colors).
 func (g *RogueGame) initColors() {
-	used := make([]bool, len(rainbow))
-	for i := 0; i < MaxPotions; i++ {
+	used := make([]bool, len(g.data.rainbow))
+
+	for i := range NumPotionTypes {
 		var j int
 		for {
-			j = g.rnd(len(rainbow))
+			j = g.rnd(len(g.data.rainbow))
 			if !used[j] {
 				break
 			}
 		}
+
 		used[j] = true
-		g.Items.PotColors[i] = rainbow[j]
+		g.Items.PotColors[i] = g.data.rainbow[j]
 	}
 }
 
 // initNames generates the names of the various scrolls (init.c init_names).
 func (g *RogueGame) initNames() {
-	for i := 0; i < MaxScrolls; i++ {
+	for i := range NumScrollTypes {
 		var cp strings.Builder
+
 		nwords := g.rnd(3) + 2
 		for ; nwords > 0; nwords-- {
 			nsyl := g.rnd(3) + 1
 			for ; nsyl > 0; nsyl-- {
-				sp := sylls[g.rnd(len(sylls))]
+				sp := g.data.sylls[g.rnd(len(g.data.sylls))]
 				if cp.Len()+len(sp) > MaxNameLen {
 					break
 				}
+
 				cp.WriteString(sp)
 			}
+
 			cp.WriteByte(' ')
 		}
+
 		g.Items.ScrNames[i] = strings.TrimSuffix(cp.String(), " ")
 	}
 }
@@ -87,47 +93,54 @@ func (g *RogueGame) initNames() {
 // initStones initializes the ring stone setting scheme for this game
 // (init.c init_stones).
 func (g *RogueGame) initStones() {
-	used := make([]bool, len(stoneTable))
-	for i := 0; i < MaxRings; i++ {
+	used := make([]bool, len(g.data.stoneTable))
+
+	for i := range NumRingTypes {
 		var j int
 		for {
-			j = g.rnd(len(stoneTable))
+			j = g.rnd(len(g.data.stoneTable))
 			if !used[j] {
 				break
 			}
 		}
+
 		used[j] = true
-		g.Items.RingStones[i] = stoneTable[j].Name
-		g.Items.Rings[i].Worth += stoneTable[j].Value
+		g.Items.RingStones[i] = g.data.stoneTable[j].Name
+		g.Items.Rings[i].Worth += g.data.stoneTable[j].Value
 	}
 }
 
 // initMaterials initializes the construction materials for wands and staffs
 // (init.c init_materials).
 func (g *RogueGame) initMaterials() {
-	used := make([]bool, len(woods))
-	metused := make([]bool, len(metals))
-	for i := 0; i < MaxSticks; i++ {
+	used := make([]bool, len(g.data.woods))
+	metused := make([]bool, len(g.data.metals))
+
+	for i := range NumWandTypes {
 		var str string
+
 		for {
 			if g.rnd(2) == 0 {
-				j := g.rnd(len(metals))
+				j := g.rnd(len(g.data.metals))
 				if !metused[j] {
-					g.Items.WandType[i] = "wand"
-					str = metals[j]
+					g.Items.WandType[i] = wandName
+					str = g.data.metals[j]
 					metused[j] = true
+
 					break
 				}
 			} else {
-				j := g.rnd(len(woods))
+				j := g.rnd(len(g.data.woods))
 				if !used[j] {
-					g.Items.WandType[i] = "staff"
-					str = woods[j]
+					g.Items.WandType[i] = staffName
+					str = g.data.woods[j]
 					used[j] = true
+
 					break
 				}
 			}
 		}
+
 		g.Items.WandMade[i] = str
 	}
 }
@@ -143,28 +156,29 @@ func sumProbs(info []ObjInfo) {
 // initProbs copies the base tables into the game and initializes the
 // probabilities for the various items (init.c init_probs).
 func (g *RogueGame) initProbs() {
-	g.Items.Things = baseThings
-	g.Items.Potions = basePotInfo
-	g.Items.Scrolls = baseScrInfo
-	g.Items.Rings = baseRingInfo
-	g.Items.Sticks = baseWsInfo
-	g.Items.Weapons = baseWeapInfo
-	g.Items.Armors = baseArmInfo
+	g.Items.Things = g.data.baseThings
+	g.Items.Potions = g.data.basePotInfo
+	g.Items.Scrolls = g.data.baseScrInfo
+	g.Items.Rings = g.data.baseRingInfo
+	g.Items.Sticks = g.data.baseWsInfo
+	g.Items.Weapons = g.data.baseWeapInfo
+	g.Items.Armors = g.data.baseArmInfo
 
 	sumProbs(g.Items.Things[:])
 	sumProbs(g.Items.Potions[:])
 	sumProbs(g.Items.Scrolls[:])
 	sumProbs(g.Items.Rings[:])
 	sumProbs(g.Items.Sticks[:])
-	sumProbs(g.Items.Weapons[:MaxWeapons]) // C sums MAXWEAPONS, excluding the flame entry
+	sumProbs(g.Items.Weapons[:NumWeaponTypes]) // C sums MAXWEAPONS, excluding the flame entry
 	sumProbs(g.Items.Armors[:])
 }
 
 // pickColor returns the given color, or a random one if the hero is
 // hallucinating (init.c pick_color).
 func (g *RogueGame) pickColor(col string) string {
-	if g.Player.On(IsHalu) {
-		return rainbow[g.rnd(len(rainbow))]
+	if g.Player.On(Hallucinating) {
+		return g.data.rainbow[g.rnd(len(g.data.rainbow))]
 	}
+
 	return col
 }

game/io.go

@@ -10,9 +10,11 @@ import (
 // maxMsg is io.c MAXMSG: how much message fits before --More--.
 const maxMsg = NumCols - len("--More--") - 1
 
-// MsgLine is the io.c message machinery: the static msgbuf/newpos pair plus
-// the related globals (mpos, huh, and the message-behavior flags).
-type MsgLine struct {
+// MessageLine is the io.c message machinery: the static msgbuf/newpos
+// pair plus the related globals (mpos, huh, and the message-behavior
+// flags). It owns the top line of the screen; attach wires in the
+// display and input it needs.
+type MessageLine struct {
 	buf      strings.Builder // msgbuf
 	newpos   int
 	Mpos     int    // where cursor is on top line
@@ -20,84 +22,137 @@ type MsgLine struct {
 	SaveMsg  bool   // remember last msg
 	LowerMsg bool   // messages should start w/lower case
 	MsgEsc   bool   // check for ESC from msg's --More--
+
+	scr      *Screen           // the top line lives on scr.Std
+	look     func(wakeup bool) // redraw before a --More-- (misc.c look)
+	readChar func() byte       // input for --More-- prompts
 }
 
 // Msg displays a message at the top of the screen (io.c msg). It returns
-// Escape if the player escaped out of a --More--, ^Escape otherwise (the C
-// convention: callers compare against ESCAPE).
-func (g *RogueGame) msg(format string, a ...any) int {
+// Escape if the player escaped out of a --More--, ^Escape otherwise (the
+// C convention: callers compare against ESCAPE).
+func (m *MessageLine) Msg(format string, a ...any) int {
 	// if the string is "", just clear the line
 	if format == "" {
-		g.move(0, 0)
-		g.clrtoeol()
-		g.Msgs.Mpos = 0
+		m.scr.Std.Move(0, 0)
+		m.scr.Std.Clrtoeol()
+		m.Mpos = 0
+
 		return ^Escape
 	}
 	// otherwise add to the message and flush it out
-	g.doadd(format, a...)
-	return g.endmsg()
+	m.doaddf(format, a...)
+
+	return m.End()
 }
 
-// addmsg adds things to the current message (io.c addmsg).
-func (g *RogueGame) addmsg(format string, a ...any) {
-	g.doadd(format, a...)
+// Addf adds things to the current message (io.c addmsg).
+func (m *MessageLine) Addf(format string, a ...any) {
+	m.doaddf(format, a...)
 }
 
-// endmsg displays a new msg, giving the player a chance to see the previous
+// End displays a new msg, giving the player a chance to see the previous
 // one if it is up there with the --More-- (io.c endmsg).
-func (g *RogueGame) endmsg() int {
-	m := &g.Msgs
+func (m *MessageLine) End() int {
 	if m.SaveMsg {
 		m.Huh = m.buf.String()
 	}
-	if m.Mpos != 0 {
-		g.look(false)
-		g.mvaddstr(0, m.Mpos, "--More--")
-		g.refresh()
-		if !m.MsgEsc {
-			g.waitFor(' ')
-		} else {
-			for {
-				ch := g.readchar()
-				if ch == ' ' {
-					break
-				}
-				if ch == Escape {
-					m.buf.Reset()
-					m.Mpos = 0
-					m.newpos = 0
-					return Escape
-				}
-			}
-		}
+
+	if m.Mpos != 0 && m.promptMore() == Escape {
+		return Escape
 	}
 	// All messages should start with uppercase, except ones that start
 	// with a pack addressing character
 	out := m.buf.String()
 	if len(out) > 0 && isLower(out[0]) && !m.LowerMsg &&
-		!(len(out) > 1 && out[1] == ')') {
+		(len(out) <= 1 || out[1] != ')') {
 		out = string(toUpper(out[0])) + out[1:]
 	}
-	g.mvaddstr(0, 0, out)
-	g.clrtoeol()
+
+	m.scr.Std.MvAddStr(0, 0, out)
+	m.scr.Std.Clrtoeol()
+
 	m.Mpos = m.newpos
 	m.newpos = 0
 	m.buf.Reset()
-	g.refresh()
+	m.scr.Refresh()
+
 	return ^Escape
 }
 
-// doadd performs an add onto the message buffer (io.c doadd).
-func (g *RogueGame) doadd(format string, a ...any) {
-	m := &g.Msgs
+// promptMore shows the --More-- prompt and waits for the reader to
+// acknowledge; Escape means the player bailed out (the Mpos block of
+// io.c endmsg).
+func (m *MessageLine) promptMore() int {
+	m.look(false)
+	m.scr.Std.MvAddStr(0, m.Mpos, "--More--")
+	m.scr.Refresh()
+
+	if !m.MsgEsc {
+		m.waitForSpace()
+
+		return ^Escape
+	}
+
+	for {
+		ch := m.readChar()
+		if ch == ' ' {
+			return ^Escape
+		}
+
+		if ch == Escape {
+			m.buf.Reset()
+			m.Mpos = 0
+			m.newpos = 0
+
+			return Escape
+		}
+	}
+}
+
+// attach wires the message line to its display and input; NewGame and
+// Restore call it once the screen and game exist.
+func (m *MessageLine) attach(scr *Screen, look func(bool), readChar func() byte) {
+	m.scr = scr
+	m.look = look
+	m.readChar = readChar
+}
+
+// waitForSpace absorbs input until the player types a space: the
+// --More-- acknowledgement (io.c wait_for).
+func (m *MessageLine) waitForSpace() {
+	for {
+		if m.readChar() == ' ' {
+			return
+		}
+	}
+}
+
+// doaddf performs an add onto the message buffer (io.c doadd).
+func (m *MessageLine) doaddf(format string, a ...any) {
 	s := fmt.Sprintf(format, a...)
 	if len(s)+m.newpos >= maxMsg {
-		g.endmsg()
+		m.End()
 	}
+
 	m.buf.WriteString(s)
 	m.newpos = m.buf.Len()
 }
 
+// msg, addmsgf, and endmsg are the game-side shorthands for the message
+// line; the machinery lives on MessageLine.
+func (g *RogueGame) msg(format string, a ...any) int {
+	return g.Msgs.Msg(format, a...)
+}
+
+func (g *RogueGame) addmsgf(format string, a ...any) {
+	g.Msgs.Addf(format, a...)
+}
+
+func (g *RogueGame) endmsg() {
+	g.Msgs.End()
+}
+
 // stepOk returns true if it is ok to step on ch (io.c step_ok).
 func stepOk(ch byte) bool {
 	switch ch {
@@ -114,8 +169,10 @@ func (g *RogueGame) readchar() byte {
 	ch := g.scr.term.ReadChar()
 	if ch == 3 { // ^C
 		g.quit(0)
+
 		return 27
 	}
+
 	return ch
 }
 
@@ -133,8 +190,6 @@ type statusCache struct {
 	init    bool
 }
 
-var hungerStateName = [...]string{"", "Hungry", "Weak", "Faint"}
-
 // status displays the important stats line, keeping the cursor where it was
 // (io.c status).
 func (g *RogueGame) status() {
@@ -142,21 +197,23 @@ func (g *RogueGame) status() {
 	p := &g.Player
 
 	// If nothing has changed since the last status, don't bother.
-	temp := p.Stats.Arm
+	temp := p.Stats.ArmorClass
 	if p.CurArmor != nil {
-		temp = p.CurArmor.Arm
+		temp = p.CurArmor.ArmorClass
 	}
-	if s.init && s.hp == p.Stats.HP && s.exp == p.Stats.Exp &&
-		s.pur == p.Purse && s.arm == temp && s.str == p.Stats.Str &&
-		s.lvl == g.Depth && s.hungry == p.HungryState && !g.StatMsg {
+
+	if g.statusUnchanged(temp) {
 		return
 	}
+
 	s.init = true
 	s.arm = temp
 
 	oy, ox := g.scr.Std.GetYX()
+
 	if s.hp != p.Stats.MaxHP {
 		s.hp = p.Stats.MaxHP
+
 		s.hpwidth = 0
 		for t := p.Stats.MaxHP; t != 0; t /= 10 {
 			s.hpwidth++
@@ -175,7 +232,7 @@ func (g *RogueGame) status() {
 		"Level: %d  Gold: %-5d  Hp: %*d(%*d)  Str: %2d(%d)  Arm: %-2d  Exp: %d/%d  %s",
 		g.Depth, p.Purse, s.hpwidth, p.Stats.HP, s.hpwidth, p.Stats.MaxHP,
 		p.Stats.Str, p.MaxStats.Str, 10-s.arm, p.Stats.Lvl, p.Stats.Exp,
-		hungerStateName[p.HungryState])
+		g.data.hungerStateName[p.HungryState])
 	if g.StatMsg {
 		g.move(0, 0)
 		g.msg("%s", line)
@@ -183,10 +240,23 @@ func (g *RogueGame) status() {
 		g.move(StatLine, 0)
 		g.addstr(line)
 	}
+
 	g.clrtoeol()
 	g.move(oy, ox)
 }
 
+// statusUnchanged reports whether the status line still shows current
+// values, so it need not be redrawn (the shadow-variable check of io.c
+// status). temp is the effective armor class.
+func (g *RogueGame) statusUnchanged(temp int) bool {
+	s := &g.statusCache
+	p := &g.Player
+
+	return s.init && s.hp == p.Stats.HP && s.exp == p.Stats.Exp &&
+		s.pur == p.Purse && s.arm == temp && s.str == p.Stats.Str &&
+		s.lvl == g.Depth && s.hungry == p.HungryState && !g.StatMsg
+}
+
 // waitFor sits around until the guy types the right key (io.c wait_for).
 func (g *RogueGame) waitFor(ch byte) {
 	if ch == '\n' {
@@ -197,7 +267,11 @@ func (g *RogueGame) waitFor(ch byte) {
 			}
 		}
 	}
-	for g.readchar() != ch {
+
+	for {
+		if g.readchar() == ch {
+			return
+		}
 	}
 }
 
@@ -221,11 +295,13 @@ func toUpper(c byte) byte {
 	if isLower(c) {
 		return c - 'a' + 'A'
 	}
+
 	return c
 }
 func toLower(c byte) byte {
 	if isUpper(c) {
 		return c - 'A' + 'a'
 	}
+
 	return c
 }

game/level.go

@@ -10,13 +10,13 @@ type Place struct {
 // Level is the current dungeon level: the map and everything on it. It is
 // reset in place by NewLevel, matching the C reuse of the global arrays.
 type Level struct {
-	Places   [MaxLines * MaxCols]Place
-	Rooms    [MaxRooms]Room
-	Passages [MaxPass]Room // one pseudo-room per passage network
-	Objects  []*Object     // lvl_obj: objects on this level
-	Monsters []*Monster    // mlist: monsters on the level
-	Stairs   Coord         // location of the staircase
-	NTraps   int           // number of traps on this level
+	Places    [MaxLines * MaxCols]Place
+	Rooms     [MaxRooms]Room
+	Passages  [MaxPass]Room // one pseudo-room per passage network
+	Objects   []*Object     // lvl_obj: objects on this level
+	Monsters  []*Monster    // mlist: monsters on the level
+	Stairs    Coord         // location of the staircase
+	TrapCount int           // number of traps on this level
 }
 
 // At returns the map cell at (y, x); the C INDEX(y,x) macro, including its
@@ -47,9 +47,33 @@ func (l *Level) VisibleChar(y, x int) byte {
 	if m := l.MonsterAt(y, x); m != nil {
 		return m.Disguise
 	}
+
 	return l.Char(y, x)
 }
 
+// ObjectAt finds the unclaimed object at (y, x) (misc.c find_obj).
+func (l *Level) ObjectAt(y, x int) *Object {
+	for _, obj := range l.Objects {
+		if obj.Pos.Y == y && obj.Pos.X == x {
+			return obj
+		}
+	}
+
+	return nil
+}
+
+// AddObject puts an object on the level (list.c attach on lvl_obj).
+func (l *Level) AddObject(obj *Object) { attachObj(&l.Objects, obj) }
+
+// RemoveObject takes an object off the level (list.c detach on lvl_obj).
+func (l *Level) RemoveObject(obj *Object) { detachObj(&l.Objects, obj) }
+
+// AddMonster puts a monster on the level (list.c attach on mlist).
+func (l *Level) AddMonster(m *Monster) { attachMon(&l.Monsters, m) }
+
+// RemoveMonster takes a monster off the level (list.c detach on mlist).
+func (l *Level) RemoveMonster(m *Monster) { detachMon(&l.Monsters, m) }
+
 // goldCalc is the GOLDCALC macro: how much a gold pile is worth at depth.
 func (g *RogueGame) goldCalc() int {
 	return g.rnd(50+10*g.Depth) + 2

game/misc.go

@@ -4,159 +4,251 @@ package game
 // and small utilities. call_it arrives with the scroll/potion phase (it
 // needs the get_str line editor).
 
+// lookScan carries the state of one look() glance while it examines the
+// nine squares around the hero.
+type lookScan struct {
+	hero              Coord
+	pch               byte       // map character under the hero
+	pfl               PlaceFlags // map flags under the hero
+	wakeup            bool
+	doorStop          bool // door-stop checking applies (mid-run)
+	sy, sx, ey, ex    int
+	sumhero, diffhero int
+	passcount         int
+}
+
 // look takes a quick glance all around the player (misc.c look).
 func (g *RogueGame) look(wakeup bool) {
 	p := &g.Player
 	hero := p.Pos
-	passcount := 0
 	rp := p.Room
+
 	if g.Oldpos != hero {
 		g.eraseLamp(g.Oldpos, g.Oldrp)
 		g.Oldpos = hero
 		g.Oldrp = rp
 	}
-	ey := hero.Y + 1
-	ex := hero.X + 1
-	sx := hero.X - 1
-	sy := hero.Y - 1
-	sumhero, diffhero := 0, 0
-	if g.DoorStop && !g.Firstmove && g.Running {
-		sumhero = hero.Y + hero.X
-		diffhero = hero.Y - hero.X
+
+	s := lookScan{
+		hero:   hero,
+		wakeup: wakeup,
+		sy:     hero.Y - 1,
+		sx:     hero.X - 1,
+		ey:     hero.Y + 1,
+		ex:     hero.X + 1,
 	}
+
+	s.doorStop = g.DoorStop && !g.Firstmove
+	if s.doorStop && g.Running {
+		s.sumhero = hero.Y + hero.X
+		s.diffhero = hero.Y - hero.X
+	}
+
 	pp := g.Level.At(hero.Y, hero.X)
-	pch := pp.Ch
-	pfl := pp.Flags
+	s.pch = pp.Ch
+	s.pfl = pp.Flags
 
-	for y := sy; y <= ey; y++ {
-		if y <= 0 || y >= NumLines-1 {
-			continue
-		}
-		for x := sx; x <= ex; x++ {
-			if x < 0 || x >= NumCols {
-				continue
-			}
-			if !p.On(IsBlind) {
-				if y == hero.Y && x == hero.X {
-					continue
-				}
-			}
+	g.lookAround(&s)
 
-			pp := g.Level.At(y, x)
-			ch := pp.Ch
-			if ch == ' ' { // nothing need be done with a ' '
-				continue
-			}
-			fp := &pp.Flags
-			if pch != Door && ch != Door {
-				if (pfl & FPass) != (*fp & FPass) {
-					continue
-				}
-			}
-			if (fp.Has(FPass) || ch == Door) && (pfl.Has(FPass) || pch == Door) {
-				if hero.X != x && hero.Y != y &&
-					!stepOk(g.Level.Char(y, hero.X)) && !stepOk(g.Level.Char(hero.Y, x)) {
-					continue
-				}
-			}
-
-			tp := pp.Monst
-			if tp == nil {
-				ch = g.tripCh(y, x, ch)
-			} else if p.On(SeeMonst) && tp.On(IsInvis) {
-				if g.DoorStop && !g.Firstmove {
-					g.Running = false
-				}
-				continue
-			} else {
-				if wakeup {
-					g.wakeMonster(y, x)
-				}
-				if g.seeMonst(tp) {
-					if p.On(IsHalu) {
-						ch = byte(g.rnd(26) + 'A')
-					} else {
-						ch = tp.Disguise
-					}
-				}
-			}
-			if p.On(IsBlind) && (y != hero.Y || x != hero.X) {
-				continue
-			}
-
-			g.move(y, x)
-
-			if p.Room.Flags.Has(IsDark) && !g.Options.SeeFloor && ch == Floor {
-				ch = ' '
-			}
-
-			if tp != nil || ch != g.inch() {
-				g.addch(ch)
-			}
-
-			if g.DoorStop && !g.Firstmove && g.Running {
-				switch g.RunCh {
-				case 'h':
-					if x == ex {
-						continue
-					}
-				case 'j':
-					if y == sy {
-						continue
-					}
-				case 'k':
-					if y == ey {
-						continue
-					}
-				case 'l':
-					if x == sx {
-						continue
-					}
-				case 'y':
-					if (y+x)-sumhero >= 1 {
-						continue
-					}
-				case 'u':
-					if (y-x)-diffhero >= 1 {
-						continue
-					}
-				case 'n':
-					if (y+x)-sumhero <= -1 {
-						continue
-					}
-				case 'b':
-					if (y-x)-diffhero <= -1 {
-						continue
-					}
-				}
-				switch ch {
-				case Door:
-					if x == hero.X || y == hero.Y {
-						g.Running = false
-					}
-				case Passage:
-					if x == hero.X || y == hero.Y {
-						passcount++
-					}
-				case Floor, '|', '-', ' ':
-				default:
-					g.Running = false
-				}
-			}
-		}
-	}
-	if g.DoorStop && !g.Firstmove && passcount > 1 {
+	if s.doorStop && s.passcount > 1 {
 		g.Running = false
 	}
+
 	if !g.Running || !g.Options.Jump {
 		g.mvaddch(hero.Y, hero.X, PlayerCh)
 	}
 }
 
+// lookAround runs the nine-square scan of look().
+func (g *RogueGame) lookAround(s *lookScan) {
+	for y := s.sy; y <= s.ey; y++ {
+		if y <= 0 || y >= NumLines-1 {
+			continue
+		}
+
+		for x := s.sx; x <= s.ex; x++ {
+			if x < 0 || x >= NumCols {
+				continue
+			}
+
+			g.lookCell(s, y, x)
+		}
+	}
+}
+
+// lookCell examines one square around the hero: visibility rules, trip
+// and monster rendering, drawing, and run-stop checks (the loop body of
+// misc.c look).
+func (g *RogueGame) lookCell(s *lookScan, y, x int) {
+	pp := g.Level.At(y, x)
+	if g.lookSkips(s, pp, y, x) {
+		return
+	}
+
+	tp := pp.Monst
+
+	ch, skip := g.lookCellChar(s, tp, y, x, pp.Ch)
+	if skip {
+		return
+	}
+
+	if !g.lookShow(s, tp, ch, y, x) {
+		return
+	}
+
+	if s.doorStop && g.Running {
+		g.lookRunCheck(s, ch, y, x)
+	}
+}
+
+// lookSkips reports whether look ignores this square entirely: the
+// hero's own square when sighted, blank rock, passage squares of
+// another network, and diagonals the hero could not step to (the guard
+// chain of the misc.c look loop).
+func (g *RogueGame) lookSkips(s *lookScan, pp *Place, y, x int) bool {
+	if !g.Player.On(Blind) && y == s.hero.Y && x == s.hero.X {
+		return true
+	}
+
+	if pp.Ch == ' ' { // nothing need be done with a ' '
+		return true
+	}
+
+	return lookForeignPassage(s, pp.Flags, pp.Ch) ||
+		g.lookDiagonalBlocked(s, pp.Flags, pp.Ch, y, x)
+}
+
+// lookForeignPassage hides passage squares belonging to a different
+// passage network than the hero's (misc.c look).
+func lookForeignPassage(s *lookScan, fp PlaceFlags, ch byte) bool {
+	if s.pch != Door && ch != Door {
+		return (s.pfl & FPassage) != (fp & FPassage)
+	}
+
+	return false
+}
+
+// lookDiagonalBlocked hides diagonal door/passage squares the hero could
+// not actually step to (misc.c look).
+func (g *RogueGame) lookDiagonalBlocked(s *lookScan, fp PlaceFlags, ch byte, y, x int) bool {
+	if !fp.Has(FPassage) && ch != Door {
+		return false
+	}
+
+	if !s.pfl.Has(FPassage) && s.pch != Door {
+		return false
+	}
+
+	return s.hero.X != x && s.hero.Y != y &&
+		!stepOk(g.Level.Char(y, s.hero.X)) && !stepOk(g.Level.Char(s.hero.Y, x))
+}
+
+// lookShow draws the square if it changed; it reports false when a
+// blind hero cannot see it at all (the draw part of the look loop).
+func (g *RogueGame) lookShow(s *lookScan, tp *Monster, ch byte, y, x int) bool {
+	p := &g.Player
+	if p.On(Blind) && (y != s.hero.Y || x != s.hero.X) {
+		return false
+	}
+
+	g.move(y, x)
+
+	if p.Room.Flags.Has(Dark) && !g.Options.SeeFloor && ch == Floor {
+		ch = ' '
+	}
+
+	if tp != nil || ch != g.inch() {
+		g.addch(ch)
+	}
+
+	return true
+}
+
+// lookCellChar picks what the square shows: trip rendering for empty
+// squares, waking and disguises for monsters. skip means the square is
+// not drawn at all (the monster switch of the look loop).
+func (g *RogueGame) lookCellChar(s *lookScan, tp *Monster, y, x int, ch byte) (byte, bool) {
+	p := &g.Player
+
+	switch {
+	case tp == nil:
+		return g.tripCh(y, x, ch), false
+	case p.On(SenseMonsters) && tp.On(Invisible):
+		if g.DoorStop && !g.Firstmove {
+			g.Running = false
+		}
+
+		return ch, true
+	default:
+		if s.wakeup {
+			g.wakeMonster(y, x)
+		}
+
+		if g.seeMonst(tp) {
+			if p.On(Hallucinating) {
+				return g.randomMonsterLetter(), false
+			}
+
+			return tp.Disguise, false
+		}
+
+		return ch, false
+	}
+}
+
+// lookRunCheck decides whether what this square shows should stop a run
+// (the DoorStop tail of the misc.c look loop). Squares on the running
+// edge are ignored.
+func (g *RogueGame) lookRunCheck(s *lookScan, ch byte, y, x int) {
+	if s.atRunEdge(g.RunCh, y, x) {
+		return
+	}
+
+	switch ch {
+	case Door:
+		if x == s.hero.X || y == s.hero.Y {
+			g.Running = false
+		}
+	case Passage:
+		if x == s.hero.X || y == s.hero.Y {
+			s.passcount++
+		}
+	case Floor, '|', '-', ' ':
+	default:
+		g.Running = false
+	}
+}
+
+// atRunEdge reports whether (y, x) sits on the leading edge of the run
+// direction, where door-stop checking does not apply (the first RunCh
+// switch of the misc.c look loop).
+func (s *lookScan) atRunEdge(runCh byte, y, x int) bool {
+	switch runCh {
+	case 'h':
+		return x == s.ex
+	case 'j':
+		return y == s.sy
+	case 'k':
+		return y == s.ey
+	case 'l':
+		return x == s.sx
+	case 'y':
+		return (y+x)-s.sumhero >= 1
+	case 'u':
+		return (y-x)-s.diffhero >= 1
+	case 'n':
+		return (y+x)-s.sumhero <= -1
+	case 'b':
+		return (y-x)-s.diffhero <= -1
+	}
+
+	return false
+}
+
 // tripCh returns the character for this space, taking into account whether
 // or not the player is tripping (misc.c trip_ch).
 func (g *RogueGame) tripCh(y, x int, ch byte) byte {
-	if g.Player.On(IsHalu) && g.After {
+	if g.Player.On(Hallucinating) && g.After {
 		switch ch {
 		case Floor, ' ', Passage, '-', '|', Door, Trap:
 		default:
@@ -165,26 +257,30 @@ func (g *RogueGame) tripCh(y, x int, ch byte) byte {
 			}
 		}
 	}
+
 	return ch
 }
 
 // eraseLamp erases the area shown by a lamp in a dark room
 // (misc.c erase_lamp).
 func (g *RogueGame) eraseLamp(pos Coord, rp *Room) {
-	if !(g.Options.SeeFloor && rp.Flags&(IsGone|IsDark) == IsDark &&
-		!g.Player.On(IsBlind)) {
+	if !g.Options.SeeFloor || rp.Flags&(Gone|Dark) != Dark ||
+		g.Player.On(Blind) {
 		return
 	}
 
 	ey := pos.Y + 1
 	ex := pos.X + 1
+
 	sy := pos.Y - 1
 	for x := pos.X - 1; x <= ex; x++ {
 		for y := sy; y <= ey; y++ {
 			if y == g.Player.Pos.Y && x == g.Player.Pos.X {
 				continue
 			}
+
 			g.move(y, x)
+
 			if g.inch() == Floor {
 				g.addch(' ')
 			}
@@ -195,56 +291,56 @@ func (g *RogueGame) eraseLamp(pos Coord, rp *Room) {
 // showFloor reports whether we show the floor in her room at this time
 // (misc.c show_floor).
 func (g *RogueGame) showFloor() bool {
-	if g.Player.Room.Flags&(IsGone|IsDark) == IsDark && !g.Player.On(IsBlind) {
+	if g.Player.Room.Flags&(Gone|Dark) == Dark && !g.Player.On(Blind) {
 		return g.Options.SeeFloor
 	}
-	return true
-}
 
-// findObj finds the unclaimed object at (y, x) (misc.c find_obj).
-func (g *RogueGame) findObj(y, x int) *Object {
-	for _, obj := range g.Level.Objects {
-		if obj.Pos.Y == y && obj.Pos.X == x {
-			return obj
-		}
-	}
-	return nil
+	return true
 }
 
 // eat lets her try to eat something (misc.c eat).
 func (g *RogueGame) eat() {
-	obj := g.getItem("eat", int(Food))
-	if obj == nil {
+	obj, ok := g.promptPackItem("eat", KindFood)
+	if !ok {
 		return
 	}
-	if obj.Type != Food {
+
+	if obj.Kind != KindFood {
 		if !g.Options.Terse {
 			g.msg("ugh, you would get ill if you ate that")
 		} else {
 			g.msg("that's Inedible!")
 		}
+
 		return
 	}
+
 	p := &g.Player
 	if p.FoodLeft < 0 {
 		p.FoodLeft = 0
 	}
+
 	if p.FoodLeft += HungerTime - 200 + g.rnd(400); p.FoodLeft > StomachSize {
 		p.FoodLeft = StomachSize
 	}
+
 	p.HungryState = 0
 	if obj == p.CurWeapon {
 		p.CurWeapon = nil
 	}
-	if obj.Which == 1 {
+
+	switch {
+	case obj.Which == 1:
 		g.msg("my, that was a yummy %s", g.Fruit)
-	} else if g.rnd(100) > 70 {
+	case g.rnd(100) > 70:
 		p.Stats.Exp++
+
 		g.msg("%s, this food tastes awful", g.chooseStr("bummer", "yuk"))
 		g.checkLevel()
-	} else {
+	default:
 		g.msg("%s, that tasted good", g.chooseStr("oh, wow", "yum"))
 	}
+
 	g.leavePack(obj, false, false)
 }
 
@@ -252,38 +348,46 @@ func (g *RogueGame) eat() {
 // check_level).
 func (g *RogueGame) checkLevel() {
 	p := &g.Player
+
 	var i int
-	for i = 0; eLevels[i] != 0; i++ {
-		if eLevels[i] > p.Stats.Exp {
+	for i = 0; g.data.eLevels[i] != 0; i++ {
+		if g.data.eLevels[i] > p.Stats.Exp {
 			break
 		}
 	}
+
 	i++
 	olevel := p.Stats.Lvl
+
 	p.Stats.Lvl = i
 	if i > olevel {
 		add := g.roll(i-olevel, 10)
 		p.Stats.MaxHP += add
 		p.Stats.HP += add
+
 		g.msg("welcome to level %d", i)
 	}
 }
 
-// chgStr modifies the player's strength, keeping track of the highest it
-// has been (misc.c chg_str).
-func (g *RogueGame) chgStr(amt int) {
+// changeStrength modifies the player's strength, keeping track of the
+// highest it has been (misc.c chg_str).
+func (g *RogueGame) changeStrength(amt int) {
 	if amt == 0 {
 		return
 	}
+
 	p := &g.Player
 	addStr(&p.Stats.Str, amt)
+
 	comp := p.Stats.Str
-	if p.IsRing(Left, RAddStr) {
-		addStr(&comp, -p.CurRing[Left].Arm)
+	if p.IsRing(Left, RingAddStrength) {
+		addStr(&comp, -p.CurRing[Left].Bonus)
 	}
-	if p.IsRing(Right, RAddStr) {
-		addStr(&comp, -p.CurRing[Right].Arm)
+
+	if p.IsRing(Right, RingAddStrength) {
+		addStr(&comp, -p.CurRing[Right].Bonus)
 	}
+
 	if comp > p.MaxStats.Str {
 		p.MaxStats.Str = comp
 	}
@@ -301,26 +405,31 @@ func addStr(sp *int, amt int) {
 // addHaste adds a haste to the player (misc.c add_haste).
 func (g *RogueGame) addHaste(potion bool) bool {
 	p := &g.Player
-	if p.On(IsHaste) {
+	if p.On(Hasted) {
 		g.NoCommand += g.rnd(8)
-		p.Flags.Clear(IsRun | IsHaste)
+
+		p.Flags.Clear(Awake | Hasted)
 		g.Extinguish(DNohaste)
 		g.msg("you faint from exhaustion")
+
 		return false
 	}
-	p.Flags.Set(IsHaste)
+
+	p.Flags.Set(Hasted)
+
 	if potion {
 		g.Fuse(DNohaste, 0, g.rnd(4)+4, After)
 	}
+
 	return true
 }
 
 // aggravate aggravates all the monsters on this level (misc.c aggravate).
 func (g *RogueGame) aggravate() {
-	// runto() can splice the monster list while we walk it, so iterate a copy.
+	// runTo() can splice the monster list while we walk it, so iterate a copy.
 	monsters := append([]*Monster(nil), g.Level.Monsters...)
 	for _, mp := range monsters {
-		g.runto(mp.Pos)
+		g.runTo(mp.Pos)
 	}
 }
 
@@ -330,10 +439,12 @@ func vowelstr(str string) string {
 	if str == "" {
 		return ""
 	}
+
 	switch str[0] {
 	case 'a', 'A', 'e', 'E', 'i', 'I', 'o', 'O', 'u', 'U':
 		return "n"
 	}
+
 	return ""
 }
 
@@ -343,21 +454,25 @@ func (g *RogueGame) isCurrent(obj *Object) bool {
 	if obj == nil {
 		return false
 	}
+
 	p := &g.Player
 	if obj == p.CurArmor || obj == p.CurWeapon ||
 		obj == p.CurRing[Left] || obj == p.CurRing[Right] {
 		if !g.Options.Terse {
-			g.addmsg("That's already ")
+			g.addmsgf("That's already ")
 		}
+
 		g.msg("in use")
+
 		return true
 	}
+
 	return false
 }
 
-// getDir sets up the direction coordinate for use in various "prefix"
-// commands (misc.c get_dir).
-func (g *RogueGame) getDir() bool {
+// promptDirection sets up the direction coordinate for use in various
+// "prefix" commands (misc.c get_dir).
+func (g *RogueGame) promptDirection() bool {
 	if g.Again && g.LastDir != 0 {
 		g.Delta = g.lastDelt
 		g.DirCh = g.LastDir
@@ -367,53 +482,76 @@ func (g *RogueGame) getDir() bool {
 			prompt = "which direction? "
 			g.msg("%s", prompt)
 		}
+
 		for {
-			gotit := true
-			switch g.DirCh = g.readchar(); g.DirCh {
-			case 'h', 'H':
-				g.Delta = Coord{X: -1, Y: 0}
-			case 'j', 'J':
-				g.Delta = Coord{X: 0, Y: 1}
-			case 'k', 'K':
-				g.Delta = Coord{X: 0, Y: -1}
-			case 'l', 'L':
-				g.Delta = Coord{X: 1, Y: 0}
-			case 'y', 'Y':
-				g.Delta = Coord{X: -1, Y: -1}
-			case 'u', 'U':
-				g.Delta = Coord{X: 1, Y: -1}
-			case 'b', 'B':
-				g.Delta = Coord{X: -1, Y: 1}
-			case 'n', 'N':
-				g.Delta = Coord{X: 1, Y: 1}
-			case Escape:
+			g.DirCh = g.readchar()
+			if g.DirCh == Escape {
 				g.LastDir = 0
 				g.resetLast()
+
 				return false
-			default:
-				g.Msgs.Mpos = 0
-				g.msg("%s", prompt)
-				gotit = false
 			}
-			if gotit {
+
+			if d, ok := deltaFor(g.DirCh); ok {
+				g.Delta = d
+
 				break
 			}
+
+			g.Msgs.Mpos = 0
+			g.msg("%s", prompt)
 		}
+
 		g.DirCh = toLower(g.DirCh)
 		g.LastDir = g.DirCh
 		g.lastDelt = g.Delta
 	}
-	if g.Player.On(IsHuh) && g.rnd(5) == 0 {
-		for {
-			g.Delta.Y = g.rnd(3) - 1
-			g.Delta.X = g.rnd(3) - 1
-			if g.Delta.Y != 0 || g.Delta.X != 0 {
-				break
-			}
+
+	if g.Player.On(Confused) && g.rnd(5) == 0 {
+		g.confuseDirection()
+	}
+
+	g.Msgs.Mpos = 0
+
+	return true
+}
+
+// confuseDirection randomizes the chosen direction for a confused hero
+// (the ISHUH tail of misc.c get_dir).
+func (g *RogueGame) confuseDirection() {
+	for {
+		g.Delta.Y = g.rnd(3) - 1
+
+		g.Delta.X = g.rnd(3) - 1
+		if g.Delta.Y != 0 || g.Delta.X != 0 {
+			return
 		}
 	}
-	g.Msgs.Mpos = 0
-	return true
+}
+
+// deltaFor maps a direction key to its movement delta; ok is false for
+// keys that are not directions (the switch of misc.c get_dir).
+func deltaFor(ch byte) (Coord, bool) {
+	switch ch {
+	case 'h', 'H':
+		return Coord{X: -1, Y: 0}, true
+	case 'j', 'J':
+		return Coord{X: 0, Y: 1}, true
+	case 'k', 'K':
+		return Coord{X: 0, Y: -1}, true
+	case 'l', 'L':
+		return Coord{X: 1, Y: 0}, true
+	case 'y', 'Y':
+		return Coord{X: -1, Y: -1}, true
+	case 'u', 'U':
+		return Coord{X: 1, Y: -1}, true
+	case 'b', 'B':
+		return Coord{X: -1, Y: 1}, true
+	case 'n', 'N':
+		return Coord{X: 1, Y: 1}, true
+	}
+
+	return Coord{}, false
 }
 
 // callIt calls an object something after use (misc.c call_it).
@@ -422,6 +560,7 @@ func (g *RogueGame) callIt(info *ObjInfo) {
 		info.Guess = ""
 	} else if info.Guess == "" {
 		g.msg("%s", g.chooseTerse("call it: ", "what do you want to call it? "))
+
 		buf := ""
 		if g.getStr(&buf, g.scr.Std) == Norm {
 			if buf != "" {
@@ -431,29 +570,26 @@ func (g *RogueGame) callIt(info *ObjInfo) {
 	}
 }
 
-// thingList is misc.c rnd_thing()'s static table.
-var thingList = []byte{
-	Potion, Scroll, Ring, Stick, Food, Weapon, Armor, Stairs, Gold, Amulet,
-}
-
 // rndThing picks a random thing appropriate for this level (misc.c
 // rnd_thing).
 func (g *RogueGame) rndThing() byte {
 	var i int
 	if g.Depth >= AmuletLevel {
-		i = g.rnd(len(thingList))
+		i = g.rnd(len(g.data.thingList))
 	} else {
-		i = g.rnd(len(thingList) - 1)
+		i = g.rnd(len(g.data.thingList) - 1)
 	}
-	return thingList[i]
+
+	return g.data.thingList[i]
 }
 
 // chooseStr picks the first or second string depending on whether the
 // player is tripping (misc.c choose_str).
 func (g *RogueGame) chooseStr(ts, ns string) string {
-	if g.Player.On(IsHalu) {
+	if g.Player.On(Hallucinating) {
 		return ts
 	}
+
 	return ns
 }
 
@@ -463,8 +599,10 @@ func unctrl(ch byte) string {
 	if ch < ' ' {
 		return "^" + string(ch+'@')
 	}
+
 	if ch == 0x7f {
 		return "^?"
 	}
+
 	return string(ch)
 }

game/monsters.go

@@ -2,33 +2,24 @@ package game
 
 // monsters.c — monster creation and saving throws.
 
-// lvlMons and wandMons list monsters in rough order of vorpalness; zero
-// entries in wandMons never wander (monsters.c).
-var lvlMons = [26]byte{
-	'K', 'E', 'B', 'S', 'H', 'I', 'R', 'O', 'Z', 'L', 'C', 'Q', 'A',
-	'N', 'Y', 'F', 'T', 'W', 'P', 'X', 'U', 'M', 'V', 'G', 'J', 'D',
-}
-
-var wandMons = [26]byte{
-	'K', 'E', 'B', 'S', 'H', 0, 'R', 'O', 'Z', 0, 'C', 'Q', 'A',
-	0, 'Y', 0, 'T', 'W', 'P', 0, 'U', 'M', 'V', 'G', 'J', 0,
-}
-
 // randMonster picks a monster to show up; the lower the level, the meaner
 // the monster (monsters.c randmonster).
 func (g *RogueGame) randMonster(wander bool) byte {
-	mons := &lvlMons
+	mons := &g.data.lvlMons
 	if wander {
-		mons = &wandMons
+		mons = &g.data.wandMons
 	}
+
 	for {
 		d := g.Depth + (g.rnd(10) - 6)
 		if d < 0 {
 			d = g.rnd(5)
 		}
+
 		if d > 25 {
 			d = g.rnd(5) + 21
 		}
+
 		if mons[d] != 0 {
 			return mons[d]
 		}
@@ -38,35 +29,37 @@ func (g *RogueGame) randMonster(wander bool) byte {
 // newMonster picks a new monster and adds it to the list (monsters.c
 // new_monster).
 func (g *RogueGame) newMonster(tp *Monster, typ byte, cp Coord) {
-	levAdd := g.Depth - AmuletLevel
-	if levAdd < 0 {
-		levAdd = 0
-	}
-	attachMon(&g.Level.Monsters, tp)
+	levAdd := max(g.Depth-AmuletLevel, 0)
+
+	g.Level.AddMonster(tp)
 	tp.Type = typ
 	tp.Disguise = typ
 	tp.Pos = cp
 	g.move(cp.Y, cp.X)
 	tp.OldCh = g.inch()
-	tp.Room = g.roomin(cp)
+	tp.Room = g.roomIn(cp)
 	g.Level.SetMonsterAt(cp.Y, cp.X, tp)
 	mp := &g.Monsters[tp.Type-'A']
 	tp.Stats.Lvl = mp.Stats.Lvl + levAdd
 	tp.Stats.MaxHP = g.roll(tp.Stats.Lvl, 8)
 	tp.Stats.HP = tp.Stats.MaxHP
-	tp.Stats.Arm = mp.Stats.Arm - levAdd
+	tp.Stats.ArmorClass = mp.Stats.ArmorClass - levAdd
 	tp.Stats.Dmg = mp.Stats.Dmg
 	tp.Stats.Str = mp.Stats.Str
 	tp.Stats.Exp = mp.Stats.Exp + levAdd*10 + expAdd(tp)
+
 	tp.Flags = mp.Flags
 	if g.Depth > 29 {
-		tp.Flags.Set(IsHaste)
+		tp.Flags.Set(Hasted)
 	}
+
 	tp.Turn = true
 	tp.Pack = nil
-	if g.Player.IsWearing(RAggr) {
-		g.runto(cp)
+
+	if g.Player.IsWearing(RingAggravateMonsters) {
+		g.runTo(cp)
 	}
+
 	if typ == 'X' {
 		tp.Disguise = g.rndThing()
 	}
@@ -81,11 +74,13 @@ func expAdd(tp *Monster) int {
 	} else {
 		mod = tp.Stats.MaxHP / 6
 	}
+
 	if tp.Stats.Lvl > 9 {
 		mod *= 20
 	} else if tp.Stats.Lvl > 6 {
 		mod *= 4
 	}
+
 	return mod
 }
 
@@ -93,73 +88,115 @@ func expAdd(tp *Monster) int {
 // (monsters.c wanderer).
 func (g *RogueGame) wanderer() {
 	tp := &Monster{}
+
 	var cp Coord
 	for {
-		cp, _ = g.findFloor(nil, 0, true)
-		if g.roomin(cp) != g.Player.Room {
+		cp, _ = g.findFloor(true)
+		if g.roomIn(cp) != g.Player.Room {
 			break
 		}
 	}
+
 	g.newMonster(tp, g.randMonster(true), cp)
-	if g.Player.On(SeeMonst) {
+
+	if g.Player.On(SenseMonsters) {
 		g.standout()
-		if !g.Player.On(IsHalu) {
+
+		if !g.Player.On(Hallucinating) {
 			g.addch(tp.Type)
 		} else {
-			g.addch(byte(g.rnd(26) + 'A'))
+			g.addch(g.randomMonsterLetter())
 		}
+
 		g.standend()
 	}
-	g.runto(tp.Pos)
+
+	g.runTo(tp.Pos)
 }
 
 // wakeMonster is what to do when the hero steps next to a monster
 // (monsters.c wake_monster).
-func (g *RogueGame) wakeMonster(y, x int) *Monster {
+func (g *RogueGame) wakeMonster(y, x int) {
 	p := &g.Player
+
 	tp := g.Level.MonsterAt(y, x)
 	if tp == nil {
 		panic("can't find monster in wake_monster")
 	}
-	ch := tp.Type
+
 	// Every time he sees a mean monster, it might start chasing him
-	if !tp.On(IsRun) && g.rnd(3) != 0 && tp.On(IsMean) && !tp.On(IsHeld) &&
-		!p.IsWearing(RStealth) && !p.On(IsLevit) {
+	if g.meanWakes(tp) {
 		tp.Dest = &p.Pos
-		tp.Flags.Set(IsRun)
+		tp.Flags.Set(Awake)
 	}
-	if ch == 'M' && !p.On(IsBlind) && !p.On(IsHalu) &&
-		!tp.On(IsFound) && !tp.On(IsCanc) && tp.On(IsRun) {
-		rp := p.Room
-		if (rp != nil && !rp.Flags.Has(IsDark)) ||
-			distance(y, x, p.Pos.Y, p.Pos.X) < LampDist {
-			tp.Flags.Set(IsFound)
-			if !g.save(VsMagic) {
-				if p.On(IsHuh) {
-					g.Lengthen(DUnconfuse, g.spread(HuhDuration))
-				} else {
-					g.Fuse(DUnconfuse, 0, g.spread(HuhDuration), After)
-				}
-				p.Flags.Set(IsHuh)
-				mname := g.setMname(tp)
-				g.addmsg("%s", mname)
-				if mname != "it" {
-					g.addmsg("'")
-				}
-				g.msg("s gaze has confused you")
-			}
-		}
+
+	if g.medusaCatches(tp) {
+		g.medusaGaze(tp, y, x)
 	}
 	// Let greedy ones guard gold
-	if tp.On(IsGreed) && !tp.On(IsRun) {
-		tp.Flags.Set(IsRun)
+	if tp.On(Greedy) && !tp.On(Awake) {
+		tp.Flags.Set(Awake)
+
 		if p.Room.GoldVal != 0 {
 			tp.Dest = &p.Room.Gold
 		} else {
 			tp.Dest = &p.Pos
 		}
 	}
-	return tp
+}
+
+// meanWakes decides whether a sleeping mean monster starts the chase
+// (monsters.c wake_monster). The waking roll happens for any sleeping
+// monster, as in C.
+func (g *RogueGame) meanWakes(tp *Monster) bool {
+	p := &g.Player
+
+	return !tp.On(Awake) && g.rnd(3) != 0 && tp.On(Mean) && !tp.On(Held) &&
+		!p.IsWearing(RingStealth) && !p.On(Levitating)
+}
+
+// medusaCatches reports an uncovered, awake medusa the hero can see
+// (monsters.c wake_monster).
+func (g *RogueGame) medusaCatches(tp *Monster) bool {
+	p := &g.Player
+
+	return tp.Type == 'M' && !p.On(Blind) && !p.On(Hallucinating) &&
+		!tp.On(Found) && !tp.On(Cancelled) && tp.On(Awake)
+}
+
+// medusaGaze confuses the hero when the medusa's gaze lands (the M
+// block of monsters.c wake_monster).
+func (g *RogueGame) medusaGaze(tp *Monster, y, x int) {
+	p := &g.Player
+
+	rp := p.Room
+	if (rp == nil || rp.Flags.Has(Dark)) &&
+		distance(y, x, p.Pos.Y, p.Pos.X) >= LampDist {
+		return
+	}
+
+	tp.Flags.Set(Found)
+
+	if g.save(VsMagic) {
+		return
+	}
+
+	if p.On(Confused) {
+		g.Lengthen(DUnconfuse, g.spread(HuhDuration))
+	} else {
+		g.Fuse(DUnconfuse, 0, g.spread(HuhDuration), After)
+	}
+
+	p.Flags.Set(Confused)
+
+	mname := g.setMname(tp)
+	g.addmsgf("%s", mname)
+
+	if mname != "it" {
+		g.addmsgf("'")
+	}
+
+	g.msg("s gaze has confused you")
 }
 
 // givePack gives a pack to a monster if it deserves one (monsters.c
@@ -174,6 +211,7 @@ func (g *RogueGame) givePack(tp *Monster) {
 // save_throw).
 func (g *RogueGame) saveThrow(which int, st *Stats) bool {
 	need := 14 + which - st.Lvl/2
+
 	return g.roll(1, 20) >= need
 }
 
@@ -182,12 +220,20 @@ func (g *RogueGame) saveThrow(which int, st *Stats) bool {
 func (g *RogueGame) save(which int) bool {
 	p := &g.Player
 	if which == VsMagic {
-		if p.IsRing(Left, RProtect) {
-			which -= p.CurRing[Left].Arm
+		if p.IsRing(Left, RingProtection) {
+			which -= p.CurRing[Left].Bonus
 		}
-		if p.IsRing(Right, RProtect) {
-			which -= p.CurRing[Right].Arm
+
+		if p.IsRing(Right, RingProtection) {
+			which -= p.CurRing[Right].Bonus
 		}
 	}
+
 	return g.saveThrow(which, &p.Stats)
 }
+
+// randomMonsterLetter picks a random monster display letter, used by the
+// hallucination effects (the C rnd(26)+'A' idiom).
+func (g *RogueGame) randomMonsterLetter() byte {
+	return byte(g.rnd(26) + 'A') //nolint:gosec // G115: 'A'..'Z' fits a byte
+}

game/move.go

@@ -2,158 +2,262 @@ package game
 
 // move.c — hero movement commands.
 
-// doRun starts the hero running (move.c do_run).
-func (g *RogueGame) doRun(ch byte) {
+// startRun starts the hero running (move.c do_run).
+func (g *RogueGame) startRun(ch byte) {
 	g.Running = true
 	g.After = false
 	g.RunCh = ch
 }
 
-// doMove checks that a move is legal and handles the consequences —
-// fighting, picking up, etc. (move.c do_move).
-func (g *RogueGame) doMove(dy, dx int) {
+// moveHero checks that a move is legal and handles the consequences —
+// fighting, picking up, etc. (move.c do_move). The C `goto over`
+// re-check after a passage turn is the retry loop.
+func (g *RogueGame) moveHero(dy, dx int) {
 	p := &g.Player
+
 	g.Firstmove = false
 	if g.NoMove > 0 {
 		g.NoMove--
 		g.msg("you are still stuck in the bear trap")
+
 		return
 	}
 	// Do a confused move (maybe)
 	var nh Coord
-	if p.On(IsHuh) && g.rnd(5) != 0 {
-		nh = g.rndmove(&p.Creature)
+	if p.On(Confused) && g.rnd(5) != 0 {
+		nh = g.randomStep(&p.Creature)
 		if nh == p.Pos {
 			g.After = false
 			g.Running = false
 			g.ToDeath = false
+
 			return
 		}
 	} else {
 		nh = Coord{Y: p.Pos.Y + dy, X: p.Pos.X + dx}
 	}
 
-over:
-	// Check if he tried to move off the screen or make an illegal diagonal
-	// move, and stop him if he did.
-	hitBound := nh.X < 0 || nh.X >= NumCols || nh.Y <= 0 || nh.Y >= NumLines-1
-	var ch byte
-	var fl PlaceFlags
-	if !hitBound {
-		if !g.diagOk(p.Pos, nh) {
-			g.After = false
-			g.Running = false
+	for {
+		ch, fl, stop := g.moveTarget(nh)
+		if stop {
 			return
 		}
-		if g.Running && p.Pos == nh {
-			g.After = false
-			g.Running = false
-		}
-		fl = *g.Level.FlagsAt(nh.Y, nh.X)
-		ch = g.Level.VisibleChar(nh.Y, nh.X)
-		if !fl.Has(FReal) && ch == Floor {
-			if !p.On(IsLevit) {
-				ch = Trap
-				g.Level.SetChar(nh.Y, nh.X, Trap)
-				g.Level.FlagsAt(nh.Y, nh.X).Set(FReal)
-			}
-		} else if p.On(IsHeld) && ch != 'F' {
-			g.msg("you are being held")
+
+		turned, ndy, ndx := g.moveResolve(nh, ch, fl, dy, dx)
+		if !turned {
 			return
 		}
+
+		// the C goto over: re-check the turned move
+		dy, dx = ndy, ndx
+
+		g.turnRefresh()
+
+		nh = Coord{Y: p.Pos.Y + dy, X: p.Pos.X + dx}
 	}
-	if hitBound {
-		ch = ' ' // fall into the wall case below
-	}
+}
+
+// moveResolve acts on the square the hero stepped at: a wall may turn a
+// passage runner (reported with the new deltas); anything else completes
+// or refuses the move (the switch of move.c do_move).
+func (g *RogueGame) moveResolve(nh Coord, ch byte, fl PlaceFlags, dy, dx int) (bool, int, int) {
 	switch ch {
 	case ' ', '|', '-':
-		if g.Options.PassGo && g.Running && p.Room.Flags.Has(IsGone) &&
-			!p.On(IsBlind) {
-			var b1, b2 bool
-			switch g.RunCh {
-			case 'h', 'l':
-				b1 = p.Pos.Y != 1 && g.turnOk(p.Pos.Y-1, p.Pos.X)
-				b2 = p.Pos.Y != NumLines-2 && g.turnOk(p.Pos.Y+1, p.Pos.X)
-				if b1 != b2 {
-					if b1 {
-						g.RunCh = 'k'
-						dy = -1
-					} else {
-						g.RunCh = 'j'
-						dy = 1
-					}
-					dx = 0
-					g.turnref()
-					nh = Coord{Y: p.Pos.Y + dy, X: p.Pos.X + dx}
-					goto over
-				}
-			case 'j', 'k':
-				b1 = p.Pos.X != 0 && g.turnOk(p.Pos.Y, p.Pos.X-1)
-				b2 = p.Pos.X != NumCols-1 && g.turnOk(p.Pos.Y, p.Pos.X+1)
-				if b1 != b2 {
-					if b1 {
-						g.RunCh = 'h'
-						dx = -1
-					} else {
-						g.RunCh = 'l'
-						dx = 1
-					}
-					dy = 0
-					g.turnref()
-					nh = Coord{Y: p.Pos.Y + dy, X: p.Pos.X + dx}
-					goto over
-				}
-			}
+		if turn, ndy, ndx := g.passageTurn(dy, dx); turn {
+			return true, ndy, ndx
 		}
+
 		g.Running = false
 		g.After = false
+	default:
+		g.moveEnter(nh, fl, ch)
+	}
+
+	return false, 0, 0
+}
+
+// moveEnter completes a step onto a walkable square: doors, traps,
+// passages, floor, and things (the entry arms of the move.c do_move
+// switch).
+func (g *RogueGame) moveEnter(nh Coord, fl PlaceFlags, ch byte) {
+	p := &g.Player
+
+	switch ch {
 	case Door:
 		g.Running = false
-		if g.Level.FlagsAt(p.Pos.Y, p.Pos.X).Has(FPass) {
+		if g.Level.FlagsAt(p.Pos.Y, p.Pos.X).Has(FPassage) {
 			g.enterRoom(nh)
 		}
-		g.moveStuff(nh, fl)
 	case Trap:
-		tr := g.beTrapped(nh)
-		if tr == TDoor || tr == TTelep {
+		tr := g.springTrap(nh)
+		if tr == TrapDoor || tr == TrapTeleport {
 			return
 		}
-		g.moveStuff(nh, fl)
 	case Passage:
 		// when you're in a corridor, you don't know if you're in a maze
 		// room or not, and there ain't no way to find out if you're
 		// leaving a maze room, so it is necessary to always recalculate
 		// proom.
-		p.Room = g.roomin(p.Pos)
-		g.moveStuff(nh, fl)
+		p.Room = g.roomIn(p.Pos)
 	case Floor:
 		if !fl.Has(FReal) {
-			g.beTrapped(p.Pos)
+			g.springTrap(p.Pos)
 		}
-		g.moveStuff(nh, fl)
 	default:
-		if ch == Stairs {
-			g.SeenStairs = true
-		}
+		g.moveOnto(nh, fl, ch)
+
+		return
+	}
+
+	g.finishMove(nh, fl)
+}
+
+// offMap reports coordinates outside the walkable map (move.c do_move).
+func offMap(nh Coord) bool {
+	return nh.X < 0 || nh.X >= NumCols || nh.Y <= 0 || nh.Y >= NumLines-1
+}
+
+// moveTarget inspects the square the hero is stepping onto: bounds and
+// diagonal legality, hidden traps underfoot, and being held. stop means
+// the move is refused (the checks of move.c do_move).
+func (g *RogueGame) moveTarget(nh Coord) (byte, PlaceFlags, bool) {
+	p := &g.Player
+
+	// Check if he tried to move off the screen or make an illegal
+	// diagonal move, and stop him if he did.
+	if offMap(nh) {
+		return ' ', 0, false // fall into the wall case
+	}
+
+	if !g.diagOk(p.Pos, nh) {
+		g.After = false
 		g.Running = false
-		if isUpper(ch) || g.Level.MonsterAt(nh.Y, nh.X) != nil {
-			g.fight(nh, p.CurWeapon, false)
-		} else {
-			if ch != Stairs {
-				g.Take = ch
-			}
-			g.moveStuff(nh, fl)
+
+		return 0, 0, true
+	}
+
+	if g.Running && p.Pos == nh {
+		g.After = false
+		g.Running = false
+	}
+
+	fl := *g.Level.FlagsAt(nh.Y, nh.X)
+
+	ch := g.Level.VisibleChar(nh.Y, nh.X)
+	if !fl.Has(FReal) && ch == Floor {
+		if !p.On(Levitating) {
+			ch = Trap
+			g.Level.SetChar(nh.Y, nh.X, Trap)
+			g.Level.FlagsAt(nh.Y, nh.X).Set(FReal)
 		}
+	} else if p.On(Held) && ch != 'F' {
+		g.msg("you are being held")
+
+		return 0, 0, true
+	}
+
+	return ch, fl, false
+}
+
+// moveOnto handles stepping at a monster or onto an item (the default
+// arm of the move.c do_move switch).
+func (g *RogueGame) moveOnto(nh Coord, fl PlaceFlags, ch byte) {
+	p := &g.Player
+	if ch == Stairs {
+		g.SeenStairs = true
+	}
+
+	g.Running = false
+	if isUpper(ch) || g.Level.MonsterAt(nh.Y, nh.X) != nil {
+		g.fight(nh, p.CurWeapon, false)
+	} else {
+		if ch != Stairs {
+			g.Take = ch
+		}
+
+		g.finishMove(nh, fl)
 	}
 }
 
-// moveStuff is the move_stuff label in do_move: complete the step.
-func (g *RogueGame) moveStuff(nh Coord, fl PlaceFlags) {
+// passageTurn checks whether a runner in a gone-room passage should turn
+// the corner instead of stopping at a wall (the PASSGO block of move.c
+// do_move). It reports whether to turn and the new deltas, updating RunCh.
+func (g *RogueGame) passageTurn(dy, dx int) (bool, int, int) {
+	p := &g.Player
+	if !g.Options.PassGo || !g.Running || !p.Room.Flags.Has(Gone) ||
+		p.On(Blind) {
+		return false, dy, dx
+	}
+
+	switch g.RunCh {
+	case 'h', 'l':
+		if turn, ndy := g.passageTurnVertical(); turn {
+			return true, ndy, 0
+		}
+	case 'j', 'k':
+		if turn, ndx := g.passageTurnHorizontal(); turn {
+			return true, 0, ndx
+		}
+	}
+
+	return false, dy, dx
+}
+
+// passageTurnVertical decides whether a horizontal runner turns up or
+// down at a corner (move.c do_move).
+func (g *RogueGame) passageTurnVertical() (bool, int) {
+	p := &g.Player
+
+	b1 := p.Pos.Y != 1 && g.turnOk(p.Pos.Y-1, p.Pos.X)
+
+	b2 := p.Pos.Y != NumLines-2 && g.turnOk(p.Pos.Y+1, p.Pos.X)
+	if b1 == b2 {
+		return false, 0
+	}
+
+	if b1 {
+		g.RunCh = 'k'
+
+		return true, -1
+	}
+
+	g.RunCh = 'j'
+
+	return true, 1
+}
+
+// passageTurnHorizontal decides whether a vertical runner turns left or
+// right at a corner (move.c do_move).
+func (g *RogueGame) passageTurnHorizontal() (bool, int) {
+	p := &g.Player
+
+	b1 := p.Pos.X != 0 && g.turnOk(p.Pos.Y, p.Pos.X-1)
+
+	b2 := p.Pos.X != NumCols-1 && g.turnOk(p.Pos.Y, p.Pos.X+1)
+	if b1 == b2 {
+		return false, 0
+	}
+
+	if b1 {
+		g.RunCh = 'h'
+
+		return true, -1
+	}
+
+	g.RunCh = 'l'
+
+	return true, 1
+}
+
+// finishMove is the move_stuff label in do_move: complete the step.
+func (g *RogueGame) finishMove(nh Coord, fl PlaceFlags) {
 	p := &g.Player
 	g.mvaddch(p.Pos.Y, p.Pos.X, g.floorAt())
-	if fl.Has(FPass) && g.Level.Char(g.Oldpos.Y, g.Oldpos.X) == Door {
+
+	if fl.Has(FPassage) && g.Level.Char(g.Oldpos.Y, g.Oldpos.X) == Door {
 		g.leaveRoom(nh)
 	}
+
 	p.Pos = nh
 }
 
@@ -161,17 +265,21 @@ func (g *RogueGame) moveStuff(nh Coord, fl PlaceFlags) {
 // (move.c turn_ok).
 func (g *RogueGame) turnOk(y, x int) bool {
 	pp := g.Level.At(y, x)
-	return pp.Ch == Door || pp.Flags&(FReal|FPass) == (FReal|FPass)
+
+	return pp.Ch == Door || pp.Flags&(FReal|FPassage) == (FReal|FPassage)
 }
 
-// turnref decides whether to refresh at a passage turning (move.c turnref).
-func (g *RogueGame) turnref() {
+// turnRefresh decides whether to refresh at a passage turning (move.c
+// turnref).
+func (g *RogueGame) turnRefresh() {
 	p := &g.Player
+
 	pp := g.Level.At(p.Pos.Y, p.Pos.X)
 	if !pp.Flags.Has(FSeen) {
 		if g.Options.Jump {
 			g.refresh()
 		}
+
 		pp.Flags.Set(FSeen)
 	}
 }
@@ -179,9 +287,10 @@ func (g *RogueGame) turnref() {
 // doorOpen is called to wake up things in a room that might move when the
 // hero enters (move.c door_open).
 func (g *RogueGame) doorOpen(rp *Room) {
-	if rp.Flags.Has(IsGone) {
+	if rp.Flags.Has(Gone) {
 		return
 	}
+
 	for y := rp.Pos.Y; y < rp.Pos.Y+rp.Max.Y; y++ {
 		for x := rp.Pos.X; x < rp.Pos.X+rp.Max.X; x++ {
 			if isUpper(g.Level.VisibleChar(y, x)) {
@@ -191,102 +300,142 @@ func (g *RogueGame) doorOpen(rp *Room) {
 	}
 }
 
-// beTrapped makes him pay for stepping on a trap (move.c be_trapped).
-func (g *RogueGame) beTrapped(tc Coord) int {
+// springTrap makes him pay for stepping on a trap (move.c be_trapped).
+func (g *RogueGame) springTrap(tc Coord) TrapKind {
 	p := &g.Player
-	if p.On(IsLevit) {
-		return TRust // anything that's not a door or teleport
+	if p.On(Levitating) {
+		return TrapRust // anything that's not a door or teleport
 	}
+
 	g.Running = false
 	g.Count = 0
 	pp := g.Level.At(tc.Y, tc.X)
 	pp.Ch = Trap
-	tr := int(pp.Flags & FTMask)
+	tr := TrapKind(pp.Flags & FTrapMask)
 	pp.Flags.Set(FSeen)
-	switch tr {
-	case TDoor:
-		g.Depth++
-		g.NewLevel()
-		g.msg("you fell into a trap!")
-	case TBear:
-		g.NoMove += g.spread(3) // BEARTIME
-		g.msg("you are caught in a bear trap")
-	case TMyst:
-		switch g.rnd(11) {
-		case 0:
-			g.msg("you are suddenly in a parallel dimension")
-		case 1:
-			g.msg("the light in here suddenly seems %s", rainbow[g.rnd(len(rainbow))])
-		case 2:
-			g.msg("you feel a sting in the side of your neck")
-		case 3:
-			g.msg("multi-colored lines swirl around you, then fade")
-		case 4:
-			g.msg("a %s light flashes in your eyes", rainbow[g.rnd(len(rainbow))])
-		case 5:
-			g.msg("a spike shoots past your ear!")
-		case 6:
-			g.msg("%s sparks dance across your armor", rainbow[g.rnd(len(rainbow))])
-		case 7:
-			g.msg("you suddenly feel very thirsty")
-		case 8:
-			g.msg("you feel time speed up suddenly")
-		case 9:
-			g.msg("time now seems to be going slower")
-		case 10:
-			g.msg("you pack turns %s!", rainbow[g.rnd(len(rainbow))])
-		}
-	case TSleep:
-		g.NoCommand += g.spread(5) // SLEEPTIME
-		p.Flags.Clear(IsRun)
-		g.msg("a strange white mist envelops you and you fall asleep")
-	case TArrow:
-		if g.swing(p.Stats.Lvl-1, p.Stats.Arm, 1) {
-			p.Stats.HP -= g.roll(1, 6)
-			if p.Stats.HP <= 0 {
-				g.msg("an arrow killed you")
-				g.death('a')
-			} else {
-				g.msg("oh no! An arrow shot you")
-			}
-		} else {
-			arrow := newObject()
-			g.initWeapon(arrow, Arrow)
-			arrow.Count = 1
-			arrow.Pos = p.Pos
-			g.fall(arrow, false)
-			g.msg("an arrow shoots past you")
-		}
-	case TTelep:
-		// since the hero's leaving, look() won't put a TRAP down for us,
-		// so we have to do it ourself
-		g.teleport()
-		g.mvaddch(tc.Y, tc.X, Trap)
-	case TDart:
-		if !g.swing(p.Stats.Lvl+1, p.Stats.Arm, 1) {
-			g.msg("a small dart whizzes by your ear and vanishes")
-		} else {
-			p.Stats.HP -= g.roll(1, 4)
-			if p.Stats.HP <= 0 {
-				g.msg("a poisoned dart killed you")
-				g.death('d')
-			}
-			if !p.IsWearing(RSustStr) && !g.save(VsPoison) {
-				g.chgStr(-1)
-			}
-			g.msg("a small dart just hit you in the shoulder")
-		}
-	case TRust:
-		g.msg("a gush of water hits you on the head")
-		g.rustArmor(p.CurArmor)
+
+	if h := g.data.trapHandlers[tr]; h != nil {
+		h(g, tc)
 	}
+
 	g.flushType()
+
 	return tr
 }
 
-// rndmove moves in a random direction if the monster/person is confused
-// (move.c rndmove).
-func (g *RogueGame) rndmove(who *Creature) Coord {
+// The per-trap effect handlers, dispatched through
+// gameData.trapHandlers. Each is one case of the C be_trapped switch.
+
+func (g *RogueGame) trapFall(Coord) {
+	g.Depth++
+	g.NewLevel()
+	g.msg("you fell into a trap!")
+}
+
+func (g *RogueGame) trapBear(Coord) {
+	g.NoMove += g.spread(3) // BEARTIME
+	g.msg("you are caught in a bear trap")
+}
+
+func (g *RogueGame) trapMystery(Coord) {
+	which := g.rnd(11)
+	switch which {
+	case 0:
+		g.msg("you are suddenly in a parallel dimension")
+	case 1:
+		g.msg("the light in here suddenly seems %s", g.data.rainbow[g.rnd(len(g.data.rainbow))])
+	case 2:
+		g.msg("you feel a sting in the side of your neck")
+	case 3:
+		g.msg("multi-colored lines swirl around you, then fade")
+	case 4:
+		g.msg("a %s light flashes in your eyes", g.data.rainbow[g.rnd(len(g.data.rainbow))])
+	case 5:
+		g.msg("a spike shoots past your ear!")
+	default:
+		g.trapMysteryMore(which)
+	}
+}
+
+// trapMysteryMore holds the back half of the mystery-trap messages.
+func (g *RogueGame) trapMysteryMore(which int) {
+	switch which {
+	case 6:
+		g.msg("%s sparks dance across your armor", g.data.rainbow[g.rnd(len(g.data.rainbow))])
+	case 7:
+		g.msg("you suddenly feel very thirsty")
+	case 8:
+		g.msg("you feel time speed up suddenly")
+	case 9:
+		g.msg("time now seems to be going slower")
+	case 10:
+		g.msg("you pack turns %s!", g.data.rainbow[g.rnd(len(g.data.rainbow))])
+	}
+}
+
+func (g *RogueGame) trapSleep(Coord) {
+	g.NoCommand += g.spread(5) // SLEEPTIME
+
+	g.Player.Flags.Clear(Awake)
+	g.msg("a strange white mist envelops you and you fall asleep")
+}
+
+func (g *RogueGame) trapArrow(Coord) {
+	p := &g.Player
+	if g.swing(p.Stats.Lvl-1, p.Stats.ArmorClass, 1) {
+		p.Stats.HP -= g.roll(1, 6)
+		if p.Stats.HP <= 0 {
+			g.msg("an arrow killed you")
+			g.death('a')
+		} else {
+			g.msg("oh no! An arrow shot you")
+		}
+	} else {
+		arrow := newObject()
+		g.initWeapon(arrow, WeaponArrow)
+		arrow.Count = 1
+		arrow.Pos = p.Pos
+		g.fall(arrow, false)
+		g.msg("an arrow shoots past you")
+	}
+}
+
+func (g *RogueGame) trapTeleport(tc Coord) {
+	// since the hero's leaving, look() won't put a TRAP down for us,
+	// so we have to do it ourself
+	g.teleport()
+	g.mvaddch(tc.Y, tc.X, Trap)
+}
+
+func (g *RogueGame) trapDart(Coord) {
+	p := &g.Player
+	if !g.swing(p.Stats.Lvl+1, p.Stats.ArmorClass, 1) {
+		g.msg("a small dart whizzes by your ear and vanishes")
+
+		return
+	}
+
+	p.Stats.HP -= g.roll(1, 4)
+	if p.Stats.HP <= 0 {
+		g.msg("a poisoned dart killed you")
+		g.death('d')
+	}
+
+	if !p.IsWearing(RingSustainStrength) && !g.save(VsPoison) {
+		g.changeStrength(-1)
+	}
+
+	g.msg("a small dart just hit you in the shoulder")
+}
+
+func (g *RogueGame) trapRust(Coord) {
+	g.msg("a gush of water hits you on the head")
+	g.rustArmor(g.Player.CurArmor)
+}
+
+// randomStep moves in a random direction if the monster/person is
+// confused (move.c rndmove).
+func (g *RogueGame) randomStep(who *Creature) Coord {
 	ret := Coord{
 		Y: who.Pos.Y + g.rnd(3) - 1,
 		X: who.Pos.X + g.rnd(3) - 1,
@@ -296,42 +445,50 @@ func (g *RogueGame) rndmove(who *Creature) Coord {
 	if ret == who.Pos {
 		return ret
 	}
+
 	if !g.diagOk(who.Pos, ret) {
 		return who.Pos
 	}
+
 	ch := g.Level.VisibleChar(ret.Y, ret.X)
 	if !stepOk(ch) {
 		return who.Pos
 	}
+
 	if ch == Scroll {
 		var found *Object
+
 		for _, obj := range g.Level.Objects {
 			if ret.Y == obj.Pos.Y && ret.X == obj.Pos.X {
 				found = obj
+
 				break
 			}
 		}
-		if found != nil && found.Which == SScare {
+
+		if found != nil && found.ScrollKind() == ScrollScareMonster {
 			return who.Pos
 		}
 	}
+
 	return ret
 }
 
 // rustArmor rusts the given armor, if it is a legal kind to rust, and we
 // aren't wearing a magic ring (move.c rust_armor).
 func (g *RogueGame) rustArmor(arm *Object) {
-	if arm == nil || arm.Type != Armor || arm.Which == Leather ||
-		arm.Arm >= 9 {
+	if arm == nil || arm.Kind != KindArmor || arm.ArmorKind() == ArmorLeather ||
+		arm.ArmorClass >= 9 {
 		return
 	}
 
-	if arm.Flags.Has(IsProt) || g.Player.IsWearing(RSustArm) {
+	if arm.Flags.Has(Protected) || g.Player.IsWearing(RingMaintainArmor) {
 		if !g.ToDeath {
 			g.msg("the rust vanishes instantly")
 		}
 	} else {
-		arm.Arm++
+		arm.ArmorClass++
+
 		if !g.Options.Terse {
 			g.msg("your armor appears to be weaker now. Oh my!")
 		} else {

game/newlevel.go

@@ -12,7 +12,8 @@ const (
 // NewLevel digs and draws a new level (new_level.c new_level).
 func (g *RogueGame) NewLevel() {
 	p := &g.Player
-	p.Flags.Clear(IsHeld) // unhold when you go down just in case
+	p.Flags.Clear(Held) // unhold when you go down just in case
+
 	if g.Depth > g.MaxDepth {
 		g.MaxDepth = g.Depth
 	}
@@ -20,64 +21,68 @@ func (g *RogueGame) NewLevel() {
 	for i := range g.Level.Places {
 		g.Level.Places[i] = Place{Ch: ' ', Flags: FReal}
 	}
+
 	g.clear()
 	// Free up the monsters on the last level; the objects and their packs
 	// go with them (the garbage collector is our free_list).
 	g.Level.Monsters = nil
 	g.Level.Objects = nil
-	g.doRooms()    // Draw rooms
-	g.doPassages() // Draw passages
+	g.digRooms()    // Draw rooms
+	g.digPassages() // Draw passages
+
 	p.NoFood++
+
 	g.putThings() // Place objects (if any)
 	// Place the traps
 	if g.rnd(10) < g.Depth {
-		g.Level.NTraps = g.rnd(g.Depth/4) + 1
-		if g.Level.NTraps > MaxTraps {
-			g.Level.NTraps = MaxTraps
-		}
-		for i := g.Level.NTraps; i > 0; i-- {
+		g.Level.TrapCount = min(g.rnd(g.Depth/4)+1, MaxTraps)
+
+		for i := g.Level.TrapCount; i > 0; i-- {
 			// not only wouldn't it be NICE to have traps in mazes (not
 			// that we care about being nice), since the trap number is
 			// stored where the passage number is, we can't actually do it.
 			var stairs Coord
 			for {
-				stairs, _ = g.findFloor(nil, 0, false)
+				stairs, _ = g.findFloor(false)
 				if g.Level.Char(stairs.Y, stairs.X) == Floor {
 					break
 				}
 			}
+
 			sp := g.Level.FlagsAt(stairs.Y, stairs.X)
 			sp.Clear(FReal)
-			*sp |= PlaceFlags(g.rnd(NTraps))
+			*sp |= PlaceFlags(g.rnd(NumTrapTypes)) //nolint:gosec // G115: 0..7 fits
 		}
 	}
 	// Place the staircase down.
-	stairs, _ := g.findFloor(nil, 0, false)
+	stairs, _ := g.findFloor(false)
 	g.Level.Stairs = stairs
 	g.Level.SetChar(stairs.Y, stairs.X, Stairs)
 	g.SeenStairs = false
 
 	for _, tp := range g.Level.Monsters {
-		tp.Room = g.roomin(tp.Pos)
+		tp.Room = g.roomIn(tp.Pos)
 	}
 
-	hero, _ := g.findFloor(nil, 0, true)
+	hero, _ := g.findFloor(true)
 	p.Pos = hero
 	g.enterRoom(hero)
 	g.mvaddch(hero.Y, hero.X, PlayerCh)
-	if p.On(SeeMonst) {
+
+	if p.On(SenseMonsters) {
 		g.turnSee(false)
 	}
-	if p.On(IsHalu) {
+
+	if p.On(Hallucinating) {
 		g.visuals(0)
 	}
 }
 
-// rndRoom picks a room that is really there (new_level.c rnd_room).
-func (g *RogueGame) rndRoom() int {
+// randomRoom picks a room that is really there (new_level.c rnd_room).
+func (g *RogueGame) randomRoom() int {
 	for {
 		rm := g.rnd(MaxRooms)
-		if !g.Level.Rooms[rm].Flags.Has(IsGone) {
+		if !g.Level.Rooms[rm].Flags.Has(Gone) {
 			return rm
 		}
 	}
@@ -93,67 +98,66 @@ func (g *RogueGame) putThings() {
 	}
 	// check for treasure rooms, and if so, put it in.
 	if g.rnd(treasRoomChance) == 0 {
-		g.treasRoom()
+		g.treasureRoom()
 	}
 	// Do MAXOBJ attempts to put things on a level
-	for i := 0; i < MaxObj; i++ {
+	for range MaxObj {
 		if g.rnd(100) < 36 {
 			// Pick a new object and link it in the list
 			obj := g.newThing()
-			attachObj(&g.Level.Objects, obj)
+			g.Level.AddObject(obj)
 			// Put it somewhere
-			obj.Pos, _ = g.findFloor(nil, 0, false)
-			g.Level.SetChar(obj.Pos.Y, obj.Pos.X, obj.Type)
+			obj.Pos, _ = g.findFloor(false)
+			g.Level.SetChar(obj.Pos.Y, obj.Pos.X, obj.Kind.Glyph())
 		}
 	}
 	// If he is really deep in the dungeon and he hasn't found the amulet
 	// yet, put it somewhere on the ground
 	if g.Depth >= AmuletLevel && !g.HasAmulet {
 		obj := newObject()
-		attachObj(&g.Level.Objects, obj)
-		obj.Damage = "0x0"
-		obj.HurlDmg = "0x0"
-		obj.Arm = 11
-		obj.Type = Amulet
+		g.Level.AddObject(obj)
+		obj.Damage = dice("0x0")
+		obj.HurlDmg = dice("0x0")
+		obj.ArmorClass = 11
+		obj.Kind = KindAmulet
 		// Put it somewhere
-		obj.Pos, _ = g.findFloor(nil, 0, false)
+		obj.Pos, _ = g.findFloor(false)
 		g.Level.SetChar(obj.Pos.Y, obj.Pos.X, Amulet)
 	}
 }
 
-// treasRoom adds a treasure room (new_level.c treas_room).
-func (g *RogueGame) treasRoom() {
-	rp := &g.Level.Rooms[g.rndRoom()]
-	spots := (rp.Max.Y-2)*(rp.Max.X-2) - minTreas
-	if spots > maxTreas-minTreas {
-		spots = maxTreas - minTreas
-	}
+// treasureRoom adds a treasure room (new_level.c treas_room).
+func (g *RogueGame) treasureRoom() {
+	rp := &g.Level.Rooms[g.randomRoom()]
+
+	spots := min((rp.Max.Y-2)*(rp.Max.X-2)-minTreas, maxTreas-minTreas)
+
 	numMonst := g.rnd(spots) + minTreas
 	for nm := numMonst; nm > 0; nm-- {
 		mp, _ := g.findFloorIn(rp, 2*maxTries, false)
 		tp := g.newThing()
 		tp.Pos = mp
-		attachObj(&g.Level.Objects, tp)
-		g.Level.SetChar(mp.Y, mp.X, tp.Type)
+		g.Level.AddObject(tp)
+		g.Level.SetChar(mp.Y, mp.X, tp.Kind.Glyph())
 	}
 
 	// fill up room with monsters from the next level down
-	nm := g.rnd(spots) + minTreas
-	if nm < numMonst+2 {
-		nm = numMonst + 2
-	}
+	nm := max(g.rnd(spots)+minTreas, numMonst+2)
+
 	spots = (rp.Max.Y - 2) * (rp.Max.X - 2)
 	if nm > spots {
 		nm = spots
 	}
+
 	g.Depth++
 	for ; nm > 0; nm-- {
 		if mp, ok := g.findFloorIn(rp, maxTries, true); ok {
 			tp := &Monster{}
 			g.newMonster(tp, g.randMonster(false), mp)
-			tp.Flags.Set(IsMean) // no sloughers in THIS room
+			tp.Flags.Set(Mean) // no sloughers in THIS room
 			g.givePack(tp)
 		}
 	}
+
 	g.Depth--
 }

game/newlevel_test.go

@@ -7,24 +7,30 @@ import (
 
 func genLevel(t *testing.T, seed int32) *RogueGame {
 	t.Helper()
-	g := NewGame(Config{Seed: seed})
+
+	g := New(Params{Seed: seed})
 	g.NewLevel()
+
 	return g
 }
 
 // renderMap draws the raw level map (not the screen) as text.
 func renderMap(g *RogueGame) string {
 	var sb strings.Builder
-	for y := 0; y < NumLines; y++ {
-		for x := 0; x < NumCols; x++ {
+
+	for y := range NumLines {
+		for x := range NumCols {
 			ch := g.Level.Char(y, x)
 			if m := g.Level.MonsterAt(y, x); m != nil {
 				ch = m.Type
 			}
+
 			sb.WriteByte(ch)
 		}
+
 		sb.WriteByte('\n')
 	}
+
 	return sb.String()
 }
 
@@ -32,75 +38,117 @@ func TestNewLevelInvariants(t *testing.T) {
 	for _, seed := range []int32{1, 12345, 2026, 99999} {
 		g := genLevel(t, seed)
 
-		// The staircase is somewhere real.
-		st := g.Level.Stairs
-		if g.Level.Char(st.Y, st.X) != Stairs {
-			t.Errorf("seed %d: no staircase at recorded stairs position", seed)
+		checkHeroPlacement(t, g, seed)
+		checkRoomsDrawn(t, g, seed)
+		checkMonstersPlaced(t, g, seed)
+		checkObjectsPlaced(t, g, seed)
+		checkStartingKit(t, g, seed)
+	}
+}
+
+// checkHeroPlacement verifies the staircase and hero landed on valid,
+// unoccupied cells.
+func checkHeroPlacement(t *testing.T, g *RogueGame, seed int32) {
+	t.Helper()
+
+	// The staircase is somewhere real.
+	st := g.Level.Stairs
+	if g.Level.Char(st.Y, st.X) != Stairs {
+		t.Errorf("seed %d: no staircase at recorded stairs position", seed)
+	}
+
+	// The hero stands on a walkable, monster-free cell.
+	hp := g.Player.Pos
+	if !stepOk(g.Level.Char(hp.Y, hp.X)) {
+		t.Errorf("seed %d: hero on unwalkable cell %q", seed,
+			g.Level.Char(hp.Y, hp.X))
+	}
+
+	if g.Level.MonsterAt(hp.Y, hp.X) != nil {
+		t.Errorf("seed %d: hero standing on a monster", seed)
+	}
+
+	if g.Player.Room == nil {
+		t.Errorf("seed %d: hero not in any room", seed)
+	}
+}
+
+// checkRoomsDrawn verifies rooms and floor/passages appear on the map.
+func checkRoomsDrawn(t *testing.T, g *RogueGame, seed int32) {
+	t.Helper()
+
+	m := renderMap(g)
+	if !strings.Contains(m, "|") || !strings.Contains(m, "-") {
+		t.Errorf("seed %d: no room walls drawn", seed)
+	}
+
+	if !strings.Contains(m, ".") && !strings.Contains(m, "#") {
+		t.Errorf("seed %d: no floor or passages drawn", seed)
+	}
+}
+
+// checkMonstersPlaced verifies every monster is indexed on the map and
+// placed in a room.
+func checkMonstersPlaced(t *testing.T, g *RogueGame, seed int32) {
+	t.Helper()
+
+	for _, mon := range g.Level.Monsters {
+		if g.Level.MonsterAt(mon.Pos.Y, mon.Pos.X) != mon {
+			t.Errorf("seed %d: monster %c not indexed at its position",
+				seed, mon.Type)
 		}
 
-		// The hero stands on a walkable, monster-free cell.
-		hp := g.Player.Pos
-		if !stepOk(g.Level.Char(hp.Y, hp.X)) {
-			t.Errorf("seed %d: hero on unwalkable cell %q", seed,
-				g.Level.Char(hp.Y, hp.X))
-		}
-		if g.Level.MonsterAt(hp.Y, hp.X) != nil {
-			t.Errorf("seed %d: hero standing on a monster", seed)
-		}
-		if g.Player.Room == nil {
-			t.Errorf("seed %d: hero not in any room", seed)
+		if mon.Room == nil {
+			t.Errorf("seed %d: monster %c has no room", seed, mon.Type)
 		}
+	}
+}
 
-		// Some rooms exist and are drawn.
-		m := renderMap(g)
-		if !strings.Contains(m, "|") || !strings.Contains(m, "-") {
-			t.Errorf("seed %d: no room walls drawn", seed)
-		}
-		if !strings.Contains(m, ".") && !strings.Contains(m, "#") {
-			t.Errorf("seed %d: no floor or passages drawn", seed)
-		}
+// checkObjectsPlaced verifies every level object sits on a cell
+// displaying its type (items can share cells only with monsters standing
+// on them).
+func checkObjectsPlaced(t *testing.T, g *RogueGame, seed int32) {
+	t.Helper()
 
-		// Every monster is indexed on the map and placed in a room.
-		for _, mon := range g.Level.Monsters {
-			if g.Level.MonsterAt(mon.Pos.Y, mon.Pos.X) != mon {
-				t.Errorf("seed %d: monster %c not indexed at its position",
-					seed, mon.Type)
-			}
-			if mon.Room == nil {
-				t.Errorf("seed %d: monster %c has no room", seed, mon.Type)
-			}
+	for _, obj := range g.Level.Objects {
+		ch := g.Level.Char(obj.Pos.Y, obj.Pos.X)
+		if ch != obj.Kind.Glyph() &&
+			g.Level.MonsterAt(obj.Pos.Y, obj.Pos.X) == nil {
+			t.Errorf("seed %d: object %v at (%d,%d) but map shows %q",
+				seed, obj.Kind, obj.Pos.Y, obj.Pos.X, ch)
 		}
+	}
+}
 
-		// Every level object sits on a cell displaying its type (items can
-		// share cells only with monsters standing on them).
-		for _, obj := range g.Level.Objects {
-			ch := g.Level.Char(obj.Pos.Y, obj.Pos.X)
-			if ch != obj.Type && g.Level.MonsterAt(obj.Pos.Y, obj.Pos.X) == nil {
-				t.Errorf("seed %d: object %q at (%d,%d) but map shows %q",
-					seed, obj.Type, obj.Pos.Y, obj.Pos.X, ch)
-			}
-		}
+// checkStartingKit verifies the player has her starting kit: food, armor,
+// mace, bow, arrows.
+func checkStartingKit(t *testing.T, g *RogueGame, seed int32) {
+	t.Helper()
 
-		// The player has her starting kit: food, armor, mace, bow, arrows.
-		if len(g.Player.Pack) != 5 {
-			t.Errorf("seed %d: starting pack has %d items, want 5",
-				seed, len(g.Player.Pack))
-		}
-		if g.Player.CurWeapon == nil || g.Player.CurWeapon.Which != Mace {
-			t.Errorf("seed %d: not wielding the starting mace", seed)
-		}
-		if g.Player.CurArmor == nil || g.Player.CurArmor.Which != RingMail {
-			t.Errorf("seed %d: not wearing the starting ring mail", seed)
-		}
+	if len(g.Player.Pack) != 5 {
+		t.Errorf("seed %d: starting pack has %d items, want 5",
+			seed, len(g.Player.Pack))
+	}
+
+	if g.Player.CurWeapon == nil ||
+		g.Player.CurWeapon.WeaponKind() != WeaponMace {
+		t.Errorf("seed %d: not wielding the starting mace", seed)
+	}
+
+	if g.Player.CurArmor == nil ||
+		g.Player.CurArmor.ArmorKind() != ArmorRingMail {
+		t.Errorf("seed %d: not wearing the starting ring mail", seed)
 	}
 }
 
 func TestNewLevelDeterministic(t *testing.T) {
 	a := renderMap(genLevel(t, 12345))
+
 	b := renderMap(genLevel(t, 12345))
 	if a != b {
 		t.Error("same seed produced different levels")
 	}
+
 	c := renderMap(genLevel(t, 54321))
 	if a == c {
 		t.Error("different seeds produced identical levels")
@@ -111,10 +159,11 @@ func TestNewLevelDeterministic(t *testing.T) {
 // mazes, dark rooms, traps, treasure rooms — as a crash/invariant sweep.
 func TestDeeperLevels(t *testing.T) {
 	for _, seed := range []int32{7, 42, 1000, 31337} {
-		g := NewGame(Config{Seed: seed})
+		g := New(Params{Seed: seed})
 		for depth := 1; depth <= 30; depth++ {
 			g.Depth = depth
 			g.NewLevel()
+
 			st := g.Level.Stairs
 			if g.Level.Char(st.Y, st.X) != Stairs {
 				t.Fatalf("seed %d depth %d: missing staircase", seed, depth)

game/object.go

@@ -1,42 +1,183 @@
 package game
 
+// ObjectKind is the category of an item. In C this was the o_type byte,
+// which doubled as the character drawn on the map; the port separates the
+// category (ObjectKind) from its display character (Glyph).
+type ObjectKind int
+
+// Item categories.
+const (
+	KindNone ObjectKind = iota
+	KindPotion
+	KindScroll
+	KindFood
+	KindWeapon
+	KindArmor
+	KindRing
+	KindWand // a "stick": wand or staff
+	KindAmulet
+	KindGold
+)
+
+// Prompt-filter pseudo-kinds for item selection (rogue.h CALLABLE and
+// R_OR_S): they never appear on an Object, only as getItem filters.
+const (
+	KindCallable    ObjectKind = -1
+	KindRingOrStick ObjectKind = -2
+)
+
+// Category words shared by ObjectKind.String, the discovery list, and the
+// ident table. (The bare identifiers Potion, Scroll, Ring, Gold are the
+// glyph byte constants.)
+const (
+	potionName = "potion"
+	scrollName = "scroll"
+	ringName   = "ring"
+	goldName   = "gold"
+)
+
+// Glyph returns the map/display character for this kind of object.
+func (k ObjectKind) Glyph() byte {
+	switch k {
+	case KindPotion:
+		return Potion
+	case KindScroll:
+		return Scroll
+	case KindFood:
+		return Food
+	case KindWeapon:
+		return Weapon
+	case KindArmor:
+		return Armor
+	case KindRing:
+		return Ring
+	case KindWand:
+		return Stick
+	case KindAmulet:
+		return Amulet
+	case KindGold:
+		return Gold
+	}
+
+	return ' '
+}
+
+// String names the category the way the C type_name() did.
+func (k ObjectKind) String() string {
+	switch k {
+	case KindPotion:
+		return potionName
+	case KindScroll:
+		return scrollName
+	case KindFood:
+		return "food"
+	case KindWeapon:
+		return "weapon"
+	case KindArmor:
+		return "suit of armor"
+	case KindRing:
+		return ringName
+	default:
+		return k.stringRest()
+	}
+}
+
+// objectKindForGlyph is the reverse of Glyph: what category of item does a
+// map character denote. Returns KindNone for non-item characters.
+func objectKindForGlyph(ch byte) ObjectKind {
+	switch ch {
+	case Potion:
+		return KindPotion
+	case Scroll:
+		return KindScroll
+	case Food:
+		return KindFood
+	case Weapon:
+		return KindWeapon
+	case Armor:
+		return KindArmor
+	case Ring:
+		return KindRing
+	case Stick:
+		return KindWand
+	case Amulet:
+		return KindAmulet
+	case Gold:
+		return KindGold
+	}
+
+	return KindNone
+}
+
+// MergesInPack reports whether picking up another of this kind merges into
+// an existing pack entry's count (rogue.h ISMULT).
+func (k ObjectKind) MergesInPack() bool {
+	return k == KindPotion || k == KindScroll || k == KindFood
+}
+
+// stringRest names the remaining kinds, including the ring-or-stick
+// prompt pseudo-kind (the tail of the C type_name switch).
+func (k ObjectKind) stringRest() string {
+	switch k {
+	case KindWand:
+		return "wand or staff"
+	case KindAmulet:
+		return "amulet"
+	case KindGold:
+		return goldName
+	case KindRingOrStick:
+		return "ring, wand or staff"
+	}
+
+	return "bizarre thing"
+}
+
 // Object is the _o arm of the C THING union: anything that can lie on the
 // floor or ride in a pack.
 type Object struct {
-	Type    byte   // what kind of object it is (Potion, Scroll, Weapon, ...)
-	Pos     Coord  // where it lives on the screen
-	Text    string // what it says if you read it
-	Launch  int    // what you need to launch it (weapon index, -1 none)
-	PackCh  byte   // what character it is in the pack
-	Damage  string // damage if used like sword
-	HurlDmg string // damage if thrown
-	Count   int    // count for plural objects
-	Which   int    // which object of a type it is
-	HPlus   int    // plusses to hit
-	DPlus   int    // plusses to damage
-	Arm     int    // armor protection — overloaded as in C (see Charges/GoldVal)
-	Flags   ObjFlags
-	Group   int    // group number for this object
-	Label   string // label for object
+	Kind       ObjectKind // what kind of object it is (o_type)
+	Pos        Coord      // where it lives on the screen
+	Text       string     // what it says if you read it
+	Launch     WeaponKind // what you need to launch it (noWeapon if none)
+	PackCh     byte       // what character it is in the pack
+	Damage     DiceSpec   // damage if used like sword
+	HurlDmg    DiceSpec   // damage if thrown
+	Count      int        // count for plural objects
+	Which      int        // which object of a type it is (index for the Kind's table)
+	HPlus      int        // plusses to hit
+	DPlus      int        // plusses to damage
+	ArmorClass int        // armor protection (armor only)
+	Charges    int        // charges remaining (wands and staffs only)
+	GoldValue  int        // worth (gold piles only)
+	Bonus      int        // magic bonus (rings only: protection, add strength, ...)
+	Flags      ObjFlags
+	Group      int    // group number for this object
+	Label      string // label for object
 }
 
 // newObject is list.c new_item() for objects: a zeroed Object with the
 // same non-zero defaults the C code relies on.
 func newObject() *Object {
-	return &Object{Launch: -1}
+	return &Object{Launch: noWeapon}
 }
 
-// Charges is the o_charges alias for Arm on wands and staffs.
-func (o *Object) Charges() int { return o.Arm }
+// PotionKind returns Which as a potion kind; valid only for KindPotion.
+func (o *Object) PotionKind() PotionKind { return PotionKind(o.Which) }
 
-// SetCharges stores a charge count in the overloaded Arm field.
-func (o *Object) SetCharges(n int) { o.Arm = n }
+// ScrollKind returns Which as a scroll kind; valid only for KindScroll.
+func (o *Object) ScrollKind() ScrollKind { return ScrollKind(o.Which) }
 
-// GoldVal is the o_goldval alias for Arm on gold piles.
-func (o *Object) GoldVal() int { return o.Arm }
+// RingKind returns Which as a ring kind; valid only for KindRing.
+func (o *Object) RingKind() RingKind { return RingKind(o.Which) }
 
-// SetGoldVal stores a gold value in the overloaded Arm field.
-func (o *Object) SetGoldVal(n int) { o.Arm = n }
+// WandKind returns Which as a wand kind; valid only for KindWand.
+func (o *Object) WandKind() WandKind { return WandKind(o.Which) }
+
+// WeaponKind returns Which as a weapon kind; valid only for KindWeapon.
+func (o *Object) WeaponKind() WeaponKind { return WeaponKind(o.Which) }
+
+// ArmorKind returns Which as an armor kind; valid only for KindArmor.
+func (o *Object) ArmorKind() ArmorKind { return ArmorKind(o.Which) }
 
 // attachObj is list.c attach(): push item onto the front of a list.
 func attachObj(list *[]*Object, item *Object) {
@@ -48,6 +189,7 @@ func detachObj(list *[]*Object, item *Object) {
 	for i, o := range *list {
 		if o == item {
 			*list = append((*list)[:i], (*list)[i+1:]...)
+
 			return
 		}
 	}

game/options.go

@@ -28,6 +28,7 @@ type optDesc struct {
 // optList builds the options.c optlist for this game.
 func (g *RogueGame) optList() []optDesc {
 	o := &g.Options
+
 	return []optDesc{
 		{"terse", "Terse output", optBool, &o.Terse, nil, nil},
 		{"flush", "Flush typeahead during battle", optBool, &o.FightFlush, nil, nil},
@@ -46,6 +47,7 @@ func (g *RogueGame) optList() []optDesc {
 func (g *RogueGame) option() {
 	hw := g.scr.Hw
 	optlist := g.optList()
+
 	hw.Clear()
 	// Display current values of options
 	for i := range optlist {
@@ -56,9 +58,11 @@ func (g *RogueGame) option() {
 	}
 	// Set values
 	hw.Move(0, 0)
+
 	for i := 0; i < len(optlist); i++ {
 		op := &optlist[i]
 		g.prOptname(op)
+
 		retval := g.getOpt(op)
 		if retval != Norm {
 			if retval == Quit {
@@ -70,6 +74,7 @@ func (g *RogueGame) option() {
 				i -= 2
 			} else { // trying to back up beyond the top
 				hw.Move(0, 0)
+
 				i--
 			}
 		}
@@ -84,18 +89,19 @@ func (g *RogueGame) option() {
 
 // prOptname prints out the option name prompt (options.c pr_optname).
 func (g *RogueGame) prOptname(op *optDesc) {
-	g.scr.Hw.Printw("%s (\"%s\"): ", op.prompt, op.name)
+	g.scr.Hw.Printwf("%s (\"%s\"): ", op.prompt, op.name)
 }
 
 // putOpt prints an option's current value (options.c put_bool/put_str/
 // put_inv_t).
 func (g *RogueGame) putOpt(op *optDesc) {
 	hw := g.scr.Hw
+
 	switch op.kind {
 	case optBool, optSeeFloor:
 		hw.AddStr(boolStr(*op.boolP))
 	case optInvT:
-		hw.AddStr(invTName[*op.intP])
+		hw.AddStr(g.data.invTName[*op.intP])
 	case optStr:
 		hw.AddStr(*op.strP)
 	}
@@ -105,6 +111,7 @@ func boolStr(b bool) string {
 	if b {
 		return "True"
 	}
+
 	return "False"
 }
 
@@ -129,9 +136,11 @@ func (g *RogueGame) getBool(bp *bool) int {
 	win := g.scr.Hw
 	oy, ox := win.GetYX()
 	win.AddStr(boolStr(*bp))
+
 	for {
 		win.Move(oy, ox)
 		g.scr.RefreshWin(win)
+
 		switch g.readchar() {
 		case 't', 'T':
 			*bp = true
@@ -145,13 +154,17 @@ func (g *RogueGame) getBool(bp *bool) int {
 		default:
 			win.Move(oy, ox+10)
 			win.AddStr("(T or F)")
+
 			continue
 		}
+
 		break
 	}
+
 	win.Move(oy, ox)
 	win.AddStr(boolStr(*bp))
 	win.AddCh('\n')
+
 	return Norm
 }
 
@@ -159,10 +172,12 @@ func (g *RogueGame) getBool(bp *bool) int {
 // get_sf).
 func (g *RogueGame) getSf(bp *bool) int {
 	wasSf := g.Options.SeeFloor
+
 	retval := g.getBool(bp)
 	if retval == Quit {
 		return Quit
 	}
+
 	if wasSf != g.Options.SeeFloor {
 		if !g.Options.SeeFloor {
 			g.Options.SeeFloor = true
@@ -172,6 +187,7 @@ func (g *RogueGame) getSf(bp *bool) int {
 			g.look(false)
 		}
 	}
+
 	return Norm
 }
 
@@ -183,57 +199,36 @@ func (g *RogueGame) getStr(opt *string, win *Window) int {
 	oy, ox := win.GetYX()
 	g.scr.RefreshWin(win)
 	// loop reading in the string, and put it in a temporary buffer
-	var buf []byte
-	var c byte
+	var (
+		buf []byte
+		c   byte
+	)
 	for {
 		c = g.readchar()
-		if c == '\n' || c == '\r' || c == Escape {
+		if endsInput(c) || (len(buf) == 0 && c == '-' && !onStd) {
 			break
 		}
-		if c == 8 || c == 0x7f { // erase character
-			if len(buf) > 0 {
-				buf = buf[:len(buf)-1]
-				win.Move(oy, ox+len(displayStr(buf)))
-			}
-			win.Clrtoeol()
-			g.scr.RefreshWin(win)
-			continue
-		}
-		if c == CTRL('U') { // kill character
-			buf = buf[:0]
-			win.Move(oy, ox)
-			win.Clrtoeol()
-			g.scr.RefreshWin(win)
-			continue
-		}
-		if len(buf) == 0 {
-			if c == '-' && !onStd {
-				break
-			}
-			if c == '~' {
-				buf = append(buf, g.Home...)
-				win.AddStr(g.Home)
-				win.Clrtoeol()
-				g.scr.RefreshWin(win)
-				continue
-			}
-		}
-		if len(buf) >= MaxInp || !(isPrint(c) || c == ' ') {
-			continue // C beeps here
-		}
-		buf = append(buf, c)
-		win.AddStr(unctrl(c))
-		win.Clrtoeol()
-		g.scr.RefreshWin(win)
+
+		buf = g.getStrEdit(win, buf, c, oy, ox)
 	}
+
 	if len(buf) > 0 { // only change option if something has been typed
 		*opt = strucpy(string(buf))
 	}
-	win.MvPrintw(oy, ox, "%s\n", *opt)
+
+	win.MvPrintwf(oy, ox, "%s\n", *opt)
 	g.scr.RefreshWin(win)
+
 	if onStd {
 		g.Msgs.Mpos += len(buf)
 	}
+
+	return getStrResult(c)
+}
+
+// getStrResult maps the terminating key to the C return code (options.c
+// get_str).
+func getStrResult(c byte) int {
 	switch c {
 	case '-':
 		return Minus
@@ -244,12 +239,59 @@ func (g *RogueGame) getStr(opt *string, win *Window) int {
 	}
 }
 
+// endsInput reports the keys that finish line input (options.c get_str).
+func endsInput(c byte) bool {
+	return c == '\n' || c == '\r' || c == Escape
+}
+
+// getStrErase deletes the last character of the buffer (options.c
+// get_str).
+func getStrErase(win *Window, buf []byte, oy, ox int) []byte {
+	if len(buf) > 0 {
+		buf = buf[:len(buf)-1]
+		win.Move(oy, ox+len(displayStr(buf)))
+	}
+
+	win.Clrtoeol()
+
+	return buf
+}
+
+// getStrEdit applies one key to the line editor's buffer: erase, kill,
+// home expansion, or a typed character (options.c get_str).
+func (g *RogueGame) getStrEdit(win *Window, buf []byte, c byte, oy, ox int) []byte {
+	switch {
+	case c == 8 || c == 0x7f:
+		buf = getStrErase(win, buf, oy, ox)
+	case c == CTRL('U'): // kill character
+		buf = buf[:0]
+
+		win.Move(oy, ox)
+		win.Clrtoeol()
+	case len(buf) == 0 && c == '~':
+		buf = append(buf, g.Home...)
+		win.AddStr(g.Home)
+		win.Clrtoeol()
+	case len(buf) >= MaxInp || (!isPrint(c) && c != ' '):
+		return buf // C beeps here
+	default:
+		buf = append(buf, c)
+		win.AddStr(unctrl(c))
+		win.Clrtoeol()
+	}
+
+	g.scr.RefreshWin(win)
+
+	return buf
+}
+
 // displayStr renders a buffer the way the input echo did.
 func displayStr(buf []byte) string {
 	var sb strings.Builder
 	for _, c := range buf {
 		sb.WriteString(unctrl(c))
 	}
+
 	return sb.String()
 }
 
@@ -257,10 +299,12 @@ func displayStr(buf []byte) string {
 func (g *RogueGame) getInvT(ip *int) int {
 	win := g.scr.Hw
 	oy, ox := win.GetYX()
-	win.AddStr(invTName[*ip])
+	win.AddStr(g.data.invTName[*ip])
+
 	for {
 		win.Move(oy, ox)
 		g.scr.RefreshWin(win)
+
 		switch g.readchar() {
 		case 'o', 'O':
 			*ip = InvOver
@@ -276,11 +320,15 @@ func (g *RogueGame) getInvT(ip *int) int {
 		default:
 			win.Move(oy, ox+15)
 			win.AddStr("(O, S, or C)")
+
 			continue
 		}
+
 		break
 	}
-	win.MvPrintw(oy, ox, "%s\n", invTName[*ip])
+
+	win.MvPrintwf(oy, ox, "%s\n", g.data.invTName[*ip])
+
 	return Norm
 }
 
@@ -289,87 +337,121 @@ func (g *RogueGame) getInvT(ip *int) int {
 // "noname" (false), strings as "name=..." (options.c parse_opts).
 func (g *RogueGame) ParseOpts(str string) {
 	optlist := g.optList()
+
 	for str != "" {
 		// Get option name
 		i := 0
 		for i < len(str) && isAlpha(str[i]) {
 			i++
 		}
-		name := str[:i]
-		rest := str[i:]
-		matched := false
-		for oi := range optlist {
-			op := &optlist[oi]
-			isBoolOpt := op.kind == optBool || op.kind == optSeeFloor
-			if strings.HasPrefix(op.name, name) && name != "" {
-				matched = true
-				if isBoolOpt {
-					*op.boolP = true
-				} else {
-					// Skip to start of string value
-					for rest != "" && rest[0] == '=' {
-						rest = rest[1:]
-					}
-					val := rest
-					var prefix string
-					if val != "" && val[0] == '~' {
-						prefix = g.Home
-						val = val[1:]
-						for val != "" && val[0] == '/' {
-							val = val[1:]
-						}
-					}
-					// Skip to end of string value
-					end := strings.IndexByte(val, ',')
-					if end < 0 {
-						end = len(val)
-					}
-					word := val[:end]
-					rest = val[end:]
-					if op.kind == optInvT {
-						// check for type of inventory
-						w := word
-						if w != "" {
-							w = string(toUpper(w[0])) + w[1:]
-						}
-						for ti, tn := range invTName {
-							if strings.HasPrefix(tn, w) {
-								*op.intP = ti
-								break
-							}
-						}
-					} else {
-						*op.strP = prefix + strucpy(word)
-					}
-				}
-				break
-			} else if isBoolOpt && strings.HasPrefix(name, "no") &&
-				strings.HasPrefix(op.name, name[2:]) {
-				matched = true
-				*op.boolP = false
-				break
-			}
-		}
-		_ = matched
+
+		rest := g.parseOptName(optlist, str[:i], str[i:])
 		// skip to start of next option name
 		for rest != "" && !isAlpha(rest[0]) {
 			rest = rest[1:]
 		}
+
 		str = rest
 	}
 }
 
+// parseOptName applies one named option, returning the unconsumed
+// remainder: "name" turns a boolean on, "noname" turns it off, and
+// string options consume a value (the option scan of options.c
+// parse_opts).
+func (g *RogueGame) parseOptName(optlist []optDesc, name, rest string) string {
+	for oi := range optlist {
+		op := &optlist[oi]
+
+		isBoolOpt := op.kind == optBool || op.kind == optSeeFloor
+		if strings.HasPrefix(op.name, name) && name != "" {
+			if isBoolOpt {
+				*op.boolP = true
+
+				return rest
+			}
+
+			return g.parseOptValue(op, rest)
+		}
+
+		if isBoolOpt && strings.HasPrefix(name, "no") &&
+			strings.HasPrefix(op.name, name[2:]) {
+			*op.boolP = false
+
+			return rest
+		}
+	}
+
+	return rest
+}
+
+// parseOptValue consumes an option's "=value" from rest, storing it,
+// and returns the remainder (the string arm of options.c parse_opts).
+func (g *RogueGame) parseOptValue(op *optDesc, rest string) string {
+	// Skip to start of string value
+	for rest != "" && rest[0] == '=' {
+		rest = rest[1:]
+	}
+
+	val := rest
+
+	var prefix string
+	if val != "" && val[0] == '~' {
+		prefix = g.Home
+
+		val = val[1:]
+		for val != "" && val[0] == '/' {
+			val = val[1:]
+		}
+	}
+	// Skip to end of string value
+	end := strings.IndexByte(val, ',')
+	if end < 0 {
+		end = len(val)
+	}
+
+	word := val[:end]
+
+	if op.kind == optInvT {
+		g.parseInvType(op, word)
+	} else {
+		*op.strP = prefix + strucpy(word)
+	}
+
+	return val[end:]
+}
+
+// parseInvType matches an inventory-style name by prefix (options.c
+// parse_opts).
+func (g *RogueGame) parseInvType(op *optDesc, word string) {
+	// check for type of inventory
+	if word != "" {
+		word = string(toUpper(word[0])) + word[1:]
+	}
+
+	for ti, tn := range g.data.invTName {
+		if strings.HasPrefix(tn, word) {
+			*op.intP = ti
+
+			break
+		}
+	}
+}
+
 // strucpy copies a string keeping only printable characters, capped at
 // MAXINP (options.c strucpy).
 func strucpy(s string) string {
 	if len(s) > MaxInp {
 		s = s[:MaxInp]
 	}
+
 	var sb strings.Builder
-	for i := 0; i < len(s); i++ {
+
+	for i := range len(s) {
 		if isPrint(s[i]) || s[i] == ' ' {
 			sb.WriteByte(s[i])
 		}
 	}
+
 	return sb.String()
 }

game/pack.go

@@ -7,101 +7,26 @@ package game
 func (g *RogueGame) addPack(obj *Object, silent bool) {
 	p := &g.Player
 	fromFloor := false
+
 	if obj == nil {
-		if obj = g.findObj(p.Pos.Y, p.Pos.X); obj == nil {
+		if obj = g.Level.ObjectAt(p.Pos.Y, p.Pos.X); obj == nil {
 			return
 		}
+
 		fromFloor = true
 	}
 
 	// Check for and deal with scare monster scrolls
-	if obj.Type == Scroll && obj.Which == SScare && obj.Flags.Has(ObjIsFound) {
-		detachObj(&g.Level.Objects, obj)
-		g.mvaddch(p.Pos.Y, p.Pos.X, g.floorCh())
-		if p.Room.Flags.Has(IsGone) {
-			g.Level.SetChar(p.Pos.Y, p.Pos.X, Passage)
-		} else {
-			g.Level.SetChar(p.Pos.Y, p.Pos.X, Floor)
-		}
-		g.msg("the scroll turns to dust as you pick it up")
+	if g.pickupScareScroll(obj) {
 		return
 	}
 
-	if len(p.Pack) == 0 {
-		p.Pack = append(p.Pack, obj)
-		obj.PackCh = g.packChar()
-		p.Inpack++
-	} else {
-		// Walk the pack looking for the insertion point, keeping items of
-		// one type together and merging stackable/grouped items — a direct
-		// translation of the C linked-list walk. lp is the index to insert
-		// after; -1 after a merge means no insertion.
-		lp := -1
-		merged := false
-		for i := 0; i < len(p.Pack); i++ {
-			if p.Pack[i].Type != obj.Type {
-				lp = i
-				continue
-			}
-			// found the group of our type: scan for matching subtype
-			for p.Pack[i].Type == obj.Type && p.Pack[i].Which != obj.Which {
-				lp = i
-				if i+1 >= len(p.Pack) {
-					break
-				}
-				i++
-			}
-			op := p.Pack[i]
-			if op.Type == obj.Type && op.Which == obj.Which {
-				if IsMult(op.Type) {
-					if !g.packRoom(fromFloor, obj) {
-						return
-					}
-					op.Count++
-					obj = op
-					lp = -1
-					merged = true
-				} else if obj.Group != 0 {
-					lp = i
-					for p.Pack[i].Type == obj.Type &&
-						p.Pack[i].Which == obj.Which &&
-						p.Pack[i].Group != obj.Group {
-						lp = i
-						if i+1 >= len(p.Pack) {
-							break
-						}
-						i++
-					}
-					op = p.Pack[i]
-					if op.Type == obj.Type && op.Which == obj.Which &&
-						op.Group == obj.Group {
-						op.Count += obj.Count
-						p.Inpack--
-						if !g.packRoom(fromFloor, obj) {
-							return
-						}
-						obj = op
-						lp = -1
-						merged = true
-					}
-				} else {
-					lp = i
-				}
-			}
-			break
-		}
-
-		if !merged && lp != -1 {
-			if !g.packRoom(fromFloor, obj) {
-				return
-			}
-			obj.PackCh = g.packChar()
-			p.Pack = append(p.Pack[:lp+1],
-				append([]*Object{obj}, p.Pack[lp+1:]...)...)
-		}
+	obj, ok := g.packInsert(obj, fromFloor)
+	if !ok {
+		return
 	}
 
-	obj.Flags.Set(ObjIsFound)
+	obj.Flags.Set(WasFound)
 
 	// If this was the object of something's desire, that monster will get
 	// mad and run at the hero.
@@ -111,158 +36,323 @@ func (g *RogueGame) addPack(obj *Object, silent bool) {
 		}
 	}
 
-	if obj.Type == Amulet {
+	if obj.Kind == KindAmulet {
 		g.HasAmulet = true
 	}
 	// Notify the user
 	if !silent {
 		if !g.Options.Terse {
-			g.addmsg("you now have ")
+			g.addmsgf("you now have ")
 		}
-		g.msg("%s (%c)", g.invName(obj, !g.Options.Terse), obj.PackCh)
+
+		g.msg("%s (%c)", g.inventoryName(obj, !g.Options.Terse), obj.PackCh)
 	}
 }
 
+// pickupScareScroll crumbles a found scare monster scroll when it is
+// picked up again; it reports whether it did (pack.c add_pack).
+func (g *RogueGame) pickupScareScroll(obj *Object) bool {
+	if obj.Kind != KindScroll || obj.ScrollKind() != ScrollScareMonster ||
+		!obj.Flags.Has(WasFound) {
+		return false
+	}
+
+	p := &g.Player
+
+	g.Level.RemoveObject(obj)
+	g.mvaddch(p.Pos.Y, p.Pos.X, g.floorCh())
+
+	if p.Room.Flags.Has(Gone) {
+		g.Level.SetChar(p.Pos.Y, p.Pos.X, Passage)
+	} else {
+		g.Level.SetChar(p.Pos.Y, p.Pos.X, Floor)
+	}
+
+	g.msg("the scroll turns to dust as you pick it up")
+
+	return true
+}
+
+// packInsert places the object in the pack, keeping items of one type
+// together and merging stackable and grouped items — a translation of
+// the C linked-list walk in pack.c add_pack. It returns the pack entry
+// the object ended up as; ok is false when the pack has no room.
+func (g *RogueGame) packInsert(obj *Object, fromFloor bool) (*Object, bool) {
+	p := &g.Player
+	if len(p.Pack) == 0 {
+		p.Pack = append(p.Pack, obj)
+		obj.PackCh = p.nextPackChar()
+		p.Inpack++
+
+		return obj, true
+	}
+
+	merged := false
+
+	// lp is the index to insert after; -1 after a merge means no
+	// insertion.
+	i, lp := packScanKind(p.Pack, obj.Kind)
+	if i < len(p.Pack) {
+		i, lp = packScanWhich(p.Pack, obj, i, lp)
+
+		if op := p.Pack[i]; op.Kind == obj.Kind && op.Which == obj.Which {
+			var ok bool
+
+			obj, lp, merged, ok = g.packMatch(obj, op, i, fromFloor)
+			if !ok {
+				return nil, false
+			}
+		}
+	}
+
+	if !merged && lp != -1 {
+		if !g.packRoom(fromFloor, obj) {
+			return nil, false
+		}
+
+		obj.PackCh = p.nextPackChar()
+		p.Pack = append(p.Pack[:lp+1],
+			append([]*Object{obj}, p.Pack[lp+1:]...)...)
+	}
+
+	return obj, true
+}
+
+// packScanKind scans to the first pack entry of this kind, returning
+// its index (or the pack length) and the entry to insert after (the
+// outer scan of pack.c add_pack).
+func packScanKind(pack []*Object, kind ObjectKind) (int, int) {
+	lp := -1
+
+	i := 0
+	for ; i < len(pack); i++ {
+		if pack[i].Kind == kind {
+			break
+		}
+
+		lp = i
+	}
+
+	return i, lp
+}
+
+// packScanWhich scans within the kind group for the matching subtype
+// (the inner scan of pack.c add_pack).
+func packScanWhich(pack []*Object, obj *Object, i, lp int) (int, int) {
+	for pack[i].Kind == obj.Kind && pack[i].Which != obj.Which {
+		lp = i
+		if i+1 >= len(pack) {
+			break
+		}
+
+		i++
+	}
+
+	return i, lp
+}
+
+// packMatch merges the object with a matching pack entry when possible:
+// stackables merge counts, grouped missiles rejoin their bundle, and
+// anything else marks the insertion point (the matched-subtype switch
+// of pack.c add_pack). It returns the resulting entry, the insert-after
+// index, whether a merge happened, and ok false when the pack is full.
+func (g *RogueGame) packMatch(obj, op *Object, i int, fromFloor bool) (*Object, int, bool, bool) {
+	switch {
+	case op.Kind.MergesInPack():
+		if !g.packRoom(fromFloor, obj) {
+			return nil, 0, false, false
+		}
+
+		op.Count++
+
+		return op, -1, true, true
+	case obj.Group != 0:
+		return g.packMatchGroup(obj, i, fromFloor)
+	default:
+		return obj, i, false, true
+	}
+}
+
+// packMatchGroup rejoins a grouped missile bundle with its group entry
+// (the o_group arm of pack.c add_pack).
+func (g *RogueGame) packMatchGroup(obj *Object, i int, fromFloor bool) (*Object, int, bool, bool) {
+	p := &g.Player
+
+	lp := i
+	for p.Pack[i].Kind == obj.Kind &&
+		p.Pack[i].Which == obj.Which &&
+		p.Pack[i].Group != obj.Group {
+		lp = i
+		if i+1 >= len(p.Pack) {
+			break
+		}
+
+		i++
+	}
+
+	op := p.Pack[i]
+	if op.Kind == obj.Kind && op.Which == obj.Which &&
+		op.Group == obj.Group {
+		op.Count += obj.Count
+		p.Inpack--
+
+		if !g.packRoom(fromFloor, obj) {
+			return nil, 0, false, false
+		}
+
+		return op, -1, true, true
+	}
+
+	return obj, lp, false, true
+}
+
 // packRoom sees if there's room in the pack; if not, prints an appropriate
 // message (pack.c pack_room).
 func (g *RogueGame) packRoom(fromFloor bool, obj *Object) bool {
 	p := &g.Player
 	if p.Inpack++; p.Inpack > MaxPack {
 		if !g.Options.Terse {
-			g.addmsg("there's ")
+			g.addmsgf("there's ")
 		}
-		g.addmsg("no room")
+
+		g.addmsgf("no room")
+
 		if !g.Options.Terse {
-			g.addmsg(" in your pack")
+			g.addmsgf(" in your pack")
 		}
+
 		g.endmsg()
+
 		if fromFloor {
 			g.moveMsg(obj)
 		}
+
 		p.Inpack = MaxPack
+
 		return false
 	}
 
 	if fromFloor {
-		detachObj(&g.Level.Objects, obj)
+		g.Level.RemoveObject(obj)
 		g.mvaddch(p.Pos.Y, p.Pos.X, g.floorCh())
-		if p.Room.Flags.Has(IsGone) {
+
+		if p.Room.Flags.Has(Gone) {
 			g.Level.SetChar(p.Pos.Y, p.Pos.X, Passage)
 		} else {
 			g.Level.SetChar(p.Pos.Y, p.Pos.X, Floor)
 		}
 	}
+
 	return true
 }
 
-// leavePack takes an item out of the pack (pack.c leave_pack).
+// leavePack takes an item out of the pack (pack.c leave_pack), keeping
+// the repeat-command bookkeeping; the pack surgery is
+// Player.removeFromPack.
 func (g *RogueGame) leavePack(obj *Object, newobj, all bool) *Object {
-	p := &g.Player
-	p.Inpack--
-	nobj := obj
 	if obj.Count > 1 && !all {
 		g.LastPick = obj
-		obj.Count--
-		if obj.Group != 0 {
-			p.Inpack++
-		}
-		if newobj {
-			copied := *obj
-			nobj = &copied
-			nobj.Count = 1
-		}
 	} else {
 		g.LastPick = nil
-		p.PackUsed[obj.PackCh-'a'] = false
-		detachObj(&p.Pack, obj)
 	}
-	return nobj
-}
 
-// packChar returns the next unused pack character (pack.c pack_char).
-func (g *RogueGame) packChar() byte {
-	p := &g.Player
-	for i := range p.PackUsed {
-		if !p.PackUsed[i] {
-			p.PackUsed[i] = true
-			return byte(i) + 'a'
-		}
-	}
-	return byte(len(p.PackUsed)) + 'a' // C would walk off the array here
+	return g.Player.removeFromPack(obj, newobj, all)
 }
 
 // inventory lists what is in the pack; returns true if there is something
 // of the given type (pack.c inventory).
-func (g *RogueGame) inventory(list []*Object, typ int) bool {
+func (g *RogueGame) inventory(list []*Object, kind ObjectKind) bool {
 	g.NObjs = 0
+
 	for _, item := range list {
-		if typ != 0 && typ != int(item.Type) &&
-			!(typ == Callable && item.Type != Food && item.Type != Amulet) &&
-			!(typ == RorS && (item.Type == Ring || item.Type == Stick)) {
+		if !matchesFilter(kind, item) {
 			continue
 		}
+
 		g.NObjs++
 		g.Msgs.MsgEsc = true
-		line := string(item.PackCh) + ") " + g.invName(item, false)
+
+		line := string(item.PackCh) + ") " + g.inventoryName(item, false)
 		if g.addLine("%s", line) == Escape {
 			g.Msgs.MsgEsc = false
 			g.msg("")
+
 			return true
 		}
+
 		g.Msgs.MsgEsc = false
 	}
+
 	if g.NObjs == 0 {
-		if g.Options.Terse {
-			if typ == 0 {
-				g.msg("empty handed")
-			} else {
-				g.msg("nothing appropriate")
-			}
+		if kind == KindNone {
+			g.msg("%s", g.chooseTerse("empty handed", "you are empty handed"))
 		} else {
-			if typ == 0 {
-				g.msg("you are empty handed")
-			} else {
-				g.msg("you don't have anything appropriate")
-			}
+			g.msg("%s", g.chooseTerse("nothing appropriate",
+				"you don't have anything appropriate"))
 		}
+
 		return false
 	}
+
 	g.endLine()
+
 	return true
 }
 
 // pickUp adds something to the character's pack (pack.c pick_up).
 func (g *RogueGame) pickUp(ch byte) {
 	p := &g.Player
-	if p.On(IsLevit) {
+	if p.On(Levitating) {
 		return
 	}
 
-	obj := g.findObj(p.Pos.Y, p.Pos.X)
+	obj := g.Level.ObjectAt(p.Pos.Y, p.Pos.X)
 	if g.MoveOn {
 		g.moveMsg(obj)
+
 		return
 	}
+
 	switch ch {
 	case Gold:
 		if obj == nil {
 			return
 		}
-		g.money(obj.GoldVal())
-		detachObj(&g.Level.Objects, obj)
+
+		g.money(obj.GoldValue)
+		g.Level.RemoveObject(obj)
+
 		p.Room.GoldVal = 0
 	default:
 		g.addPack(nil, false)
 	}
 }
 
+// matchesFilter reports whether an item passes a get_item/inventory kind
+// filter (the C condition in pack.c inventory, untangled): KindNone takes
+// everything, KindCallable takes anything nameable (not food, not the
+// amulet), KindRingOrStick takes rings and wands.
+func matchesFilter(kind ObjectKind, item *Object) bool {
+	switch kind {
+	case KindNone:
+		return true
+	case KindCallable:
+		return item.Kind != KindFood && item.Kind != KindAmulet
+	case KindRingOrStick:
+		return item.Kind == KindRing || item.Kind == KindWand
+	default:
+		return item.Kind == kind
+	}
+}
+
 // moveMsg prints the message if you are just moving onto an object
 // (pack.c move_msg).
 func (g *RogueGame) moveMsg(obj *Object) {
 	if !g.Options.Terse {
-		g.addmsg("you ")
+		g.addmsgf("you ")
 	}
-	g.msg("moved onto %s", g.invName(obj, true))
+
+	g.msg("moved onto %s", g.inventoryName(obj, true))
 }
 
 // pickyInven allows the player to inventory a single item (pack.c
@@ -271,51 +361,55 @@ func (g *RogueGame) pickyInven() {
 	p := &g.Player
 	if len(p.Pack) == 0 {
 		g.msg("you aren't carrying anything")
+
 		return
 	}
+
 	if len(p.Pack) == 1 {
-		g.msg("a) %s", g.invName(p.Pack[0], false))
+		g.msg("a) %s", g.inventoryName(p.Pack[0], false))
+
 		return
 	}
+
 	g.msg("%s", g.chooseTerse("item: ", "which item do you wish to inventory: "))
 	g.Msgs.Mpos = 0
+
 	mch := g.readchar()
 	if mch == Escape {
 		g.msg("")
+
 		return
 	}
+
 	for _, obj := range p.Pack {
 		if mch == obj.PackCh {
-			g.msg("%c) %s", mch, g.invName(obj, false))
+			g.msg("%c) %s", mch, g.inventoryName(obj, false))
+
 			return
 		}
 	}
+
 	g.msg("'%s' not in pack", unctrl(mch))
 }
 
-// getItem picks something out of a pack for a purpose (pack.c get_item).
-func (g *RogueGame) getItem(purpose string, typ int) *Object {
+// promptPackItem picks something out of a pack for a purpose (pack.c
+// get_item); the second result reports whether the player chose an
+// item.
+func (g *RogueGame) promptPackItem(purpose string, kind ObjectKind) (*Object, bool) {
 	p := &g.Player
 	if len(p.Pack) == 0 {
 		g.msg("you aren't carrying anything")
-		return nil
+
+		return nil, false
 	}
+
 	if g.Again {
-		if g.LastPick != nil {
-			return g.LastPick
-		}
-		g.msg("you ran out")
-		return nil
+		return g.repeatLastItem()
 	}
+
 	for {
-		if !g.Options.Terse {
-			g.addmsg("which object do you want to ")
-		}
-		g.addmsg("%s", purpose)
-		if g.Options.Terse {
-			g.addmsg(" what")
-		}
-		g.msg("? (* for list): ")
+		g.promptItemPurpose(purpose)
+
 		ch := g.readchar()
 		g.Msgs.Mpos = 0
 		// Give the poor player a chance to abort the command
@@ -323,40 +417,77 @@ func (g *RogueGame) getItem(purpose string, typ int) *Object {
 			g.resetLast()
 			g.After = false
 			g.msg("")
-			return nil
+
+			return nil, false
 		}
+
 		g.NObjs = 1 // normal case: person types one char
 		if ch == '*' {
 			g.Msgs.Mpos = 0
-			if !g.inventory(p.Pack, typ) {
+			if !g.inventory(p.Pack, kind) {
 				g.After = false
-				return nil
+
+				return nil, false
 			}
+
 			continue
 		}
+
 		for _, obj := range p.Pack {
 			if obj.PackCh == ch {
-				return obj
+				return obj, true
 			}
 		}
+
 		g.msg("'%s' is not a valid item", unctrl(ch))
 	}
 }
 
+// repeatLastItem replays the previous selection for the repeat command
+// (pack.c get_item).
+func (g *RogueGame) repeatLastItem() (*Object, bool) {
+	if g.LastPick != nil {
+		return g.LastPick, true
+	}
+
+	g.msg("you ran out")
+
+	return nil, false
+}
+
+// promptItemPurpose prints the "which object do you want to ...?"
+// prompt (pack.c get_item).
+func (g *RogueGame) promptItemPurpose(purpose string) {
+	if !g.Options.Terse {
+		g.addmsgf("which object do you want to ")
+	}
+
+	g.addmsgf("%s", purpose)
+
+	if g.Options.Terse {
+		g.addmsgf(" what")
+	}
+
+	g.msg("? (* for list): ")
+}
+
 // money adds or subtracts gold from the pack (pack.c money).
 func (g *RogueGame) money(value int) {
 	p := &g.Player
 	p.Purse += value
 	g.mvaddch(p.Pos.Y, p.Pos.X, g.floorCh())
-	if p.Room.Flags.Has(IsGone) {
+
+	if p.Room.Flags.Has(Gone) {
 		g.Level.SetChar(p.Pos.Y, p.Pos.X, Passage)
 	} else {
 		g.Level.SetChar(p.Pos.Y, p.Pos.X, Floor)
 	}
+
 	if value > 0 {
 		if !g.Options.Terse {
-			g.addmsg("you found ")
+			g.addmsgf("you found ")
 		}
+
 		g.msg("%d gold pieces", value)
 	}
 }
@@ -364,12 +495,14 @@ func (g *RogueGame) money(value int) {
 // floorCh returns the appropriate floor character for her room
 // (pack.c floor_ch).
 func (g *RogueGame) floorCh() byte {
-	if g.Player.Room.Flags.Has(IsGone) {
+	if g.Player.Room.Flags.Has(Gone) {
 		return Passage
 	}
+
 	if g.showFloor() {
 		return Floor
 	}
+
 	return ' '
 }
 
@@ -380,6 +513,7 @@ func (g *RogueGame) floorAt() byte {
 	if ch == Floor {
 		ch = g.floorCh()
 	}
+
 	return ch
 }
 
@@ -396,5 +530,6 @@ func (g *RogueGame) chooseTerse(terse, verbose string) string {
 	if g.Options.Terse {
 		return terse
 	}
+
 	return verbose
 }

game/passages.go

@@ -2,221 +2,269 @@ package game
 
 // passages.c — draw the connecting passages.
 
-// rdesConn is the hardcoded 3x3 room adjacency matrix from do_passages.
-var rdesConn = [MaxRooms][MaxRooms]bool{
-	{false, true, false, true, false, false, false, false, false},
-	{true, false, true, false, true, false, false, false, false},
-	{false, true, false, false, false, true, false, false, false},
-	{true, false, false, false, true, false, true, false, false},
-	{false, true, false, true, false, true, false, true, false},
-	{false, false, true, false, true, false, false, false, true},
-	{false, false, false, true, false, false, false, true, false},
-	{false, false, false, false, true, false, true, false, true},
-	{false, false, false, false, false, true, false, true, false},
-}
-
-// doPassages draws all the passages on a level (passages.c do_passages).
-func (g *RogueGame) doPassages() {
-	var isconn [MaxRooms][MaxRooms]bool
-	var ingraph [MaxRooms]bool
+// digPassages draws all the passages on a level (passages.c do_passages).
+func (g *RogueGame) digPassages() {
+	var (
+		isconn  [MaxRooms][MaxRooms]bool
+		ingraph [MaxRooms]bool
+	)
 
 	// starting with one room, connect it to a random adjacent room and
 	// then pick a new room to start with.
 	roomcount := 1
 	r1 := g.rnd(MaxRooms)
 	ingraph[r1] = true
-	for {
+
+	for roomcount < MaxRooms {
 		// find a room to connect with
-		j := 0
-		r2 := -1
-		for i := 0; i < MaxRooms; i++ {
-			if rdesConn[r1][i] && !ingraph[i] {
-				if j++; g.rnd(j) == 0 {
-					r2 = i
-				}
-			}
-		}
-		if j == 0 {
-			// if no adjacent rooms are outside the graph, pick a new room
-			// to look from
+		r2 := g.pickNeighbor(r1, func(i int) bool { return !ingraph[i] })
+		if r2 < 0 {
+			// if no adjacent rooms are outside the graph, pick a new
+			// room to look from
 			for {
 				r1 = g.rnd(MaxRooms)
 				if ingraph[r1] {
 					break
 				}
 			}
-		} else {
-			// otherwise, connect new room to the graph, and draw a tunnel
-			// to it
-			ingraph[r2] = true
-			g.conn(r1, r2)
-			isconn[r1][r2] = true
-			isconn[r2][r1] = true
-			roomcount++
-		}
-		if roomcount >= MaxRooms {
-			break
+
+			continue
 		}
+		// otherwise, connect new room to the graph, and draw a tunnel
+		// to it
+		ingraph[r2] = true
+		g.connectRooms(r1, r2)
+		isconn[r1][r2] = true
+		isconn[r2][r1] = true
+		roomcount++
 	}
 
 	// attempt to add passages to the graph a random number of times so that
 	// there isn't always just one unique passage through it.
 	for roomcount = g.rnd(5); roomcount > 0; roomcount-- {
 		r1 = g.rnd(MaxRooms) // a random room to look from
-		// find an adjacent room not already connected
-		j := 0
-		r2 := -1
-		for i := 0; i < MaxRooms; i++ {
-			if rdesConn[r1][i] && !isconn[r1][i] {
-				if j++; g.rnd(j) == 0 {
-					r2 = i
-				}
-			}
-		}
-		// if there is one, connect it and look for the next added passage
-		if j != 0 {
-			g.conn(r1, r2)
+		// find an adjacent room not already connected; if there is one,
+		// connect it and look for the next added passage
+		r2 := g.pickNeighbor(r1, func(i int) bool { return !isconn[r1][i] })
+		if r2 >= 0 {
+			g.connectRooms(r1, r2)
 			isconn[r1][r2] = true
 			isconn[r2][r1] = true
 		}
 	}
-	g.passnum()
+
+	g.numberPassages()
 }
 
-// conn draws a corridor from a room in a certain direction (passages.c
-// conn).
-func (g *RogueGame) conn(r1, r2 int) {
-	var rm int
-	var direc byte
-	if r1 < r2 {
-		rm = r1
-		if r1+1 == r2 {
-			direc = 'r'
-		} else {
-			direc = 'd'
-		}
-	} else {
-		rm = r2
-		if r2+1 == r1 {
-			direc = 'r'
-		} else {
-			direc = 'd'
+// pickNeighbor reservoir-picks an adjacent room for which ok holds, or
+// -1 when there is none (passages.c do_passages).
+func (g *RogueGame) pickNeighbor(r1 int, ok func(int) bool) int {
+	j := 0
+	r2 := -1
+
+	for i := range MaxRooms {
+		if g.data.rdesConn[r1][i] && ok(i) {
+			if j++; g.rnd(j) == 0 {
+				r2 = i
+			}
 		}
 	}
-	rpf := &g.Level.Rooms[rm]
 
-	// Set up the movement variables, in two cases: first drawing one down.
-	var rpt *Room
-	var del, turnDelta, spos, epos Coord
-	var distance, turnDistance int
+	return r2
+}
+
+// corridorPlan is the movement setup connectRooms computes before it
+// digs (the local variables of passages.c conn).
+type corridorPlan struct {
+	rpf, rpt               *Room // the rooms being joined
+	del                    Coord // direction of move
+	turnDelta              Coord // direction to turn
+	spos, epos             Coord // start and end of move
+	distance, turnDistance int   // how far to move and to turn
+}
+
+// connectRooms draws a corridor from a room in a certain direction
+// (passages.c conn).
+func (g *RogueGame) connectRooms(r1, r2 int) {
+	rm, direc := connOrient(r1, r2)
+
+	var plan corridorPlan
 	if direc == 'd' {
-		rmt := rm + 3               // room # of dest
-		rpt = &g.Level.Rooms[rmt]   // room pointer of dest
-		del = Coord{X: 0, Y: 1}     // direction of move
-		spos = rpf.Pos              // start of move
-		epos = rpt.Pos              // end of move
-		if !rpf.Flags.Has(IsGone) { // if not gone pick door pos
-			for {
-				spos.X = rpf.Pos.X + g.rnd(rpf.Max.X-2) + 1
-				spos.Y = rpf.Pos.Y + rpf.Max.Y - 1
-				if !(rpf.Flags.Has(IsMaze) && !g.Level.FlagsAt(spos.Y, spos.X).Has(FPass)) {
-					break
-				}
-			}
-		}
-		if !rpt.Flags.Has(IsGone) {
-			for {
-				epos.X = rpt.Pos.X + g.rnd(rpt.Max.X-2) + 1
-				if !(rpt.Flags.Has(IsMaze) && !g.Level.FlagsAt(epos.Y, epos.X).Has(FPass)) {
-					break
-				}
-			}
-		}
-		distance = abs(spos.Y-epos.Y) - 1 // distance to move
-		turnDelta.Y = 0                   // direction to turn
-		if spos.X < epos.X {
-			turnDelta.X = 1
-		} else {
-			turnDelta.X = -1
-		}
-		turnDistance = abs(spos.X - epos.X) // how far to turn
-	} else { // setup for moving right
-		rmt := rm + 1
-		rpt = &g.Level.Rooms[rmt]
-		del = Coord{X: 1, Y: 0}
-		spos = rpf.Pos
-		epos = rpt.Pos
-		if !rpf.Flags.Has(IsGone) {
-			for {
-				spos.X = rpf.Pos.X + rpf.Max.X - 1
-				spos.Y = rpf.Pos.Y + g.rnd(rpf.Max.Y-2) + 1
-				if !(rpf.Flags.Has(IsMaze) && !g.Level.FlagsAt(spos.Y, spos.X).Has(FPass)) {
-					break
-				}
-			}
-		}
-		if !rpt.Flags.Has(IsGone) {
-			for {
-				epos.Y = rpt.Pos.Y + g.rnd(rpt.Max.Y-2) + 1
-				if !(rpt.Flags.Has(IsMaze) && !g.Level.FlagsAt(epos.Y, epos.X).Has(FPass)) {
-					break
-				}
-			}
-		}
-		distance = abs(spos.X-epos.X) - 1
-		if spos.Y < epos.Y {
-			turnDelta.Y = 1
-		} else {
-			turnDelta.Y = -1
-		}
-		turnDelta.X = 0
-		turnDistance = abs(spos.Y - epos.Y)
+		plan = g.connPlanDown(rm)
+	} else {
+		plan = g.connPlanRight(rm)
 	}
 
-	turnSpot := g.rnd(distance-1) + 1 // where turn starts
+	turnSpot := g.rnd(plan.distance-1) + 1 // where turn starts
 
 	// Draw in the doors on either side of the passage or just put #'s if
 	// the rooms are gone.
-	if !rpf.Flags.Has(IsGone) {
-		g.door(rpf, spos)
-	} else {
-		g.putpass(spos)
+	g.connEnd(plan.rpf, plan.spos)
+	g.connEnd(plan.rpt, plan.epos)
+
+	g.digCorridor(plan, turnSpot)
+}
+
+// connOrient picks the upper-left room of the pair and the digging
+// direction: right for horizontal neighbors, down otherwise (passages.c
+// conn).
+func connOrient(r1, r2 int) (int, byte) {
+	rm := min(r1, r2)
+	if abs(r1-r2) == 1 {
+		return rm, 'r'
 	}
-	if !rpt.Flags.Has(IsGone) {
-		g.door(rpt, epos)
-	} else {
-		g.putpass(epos)
+
+	return rm, 'd'
+}
+
+// connPlanDown sets up the movement variables for a corridor drawn
+// downward (passages.c conn).
+func (g *RogueGame) connPlanDown(rm int) corridorPlan {
+	rpf := &g.Level.Rooms[rm]
+	rpt := &g.Level.Rooms[rm+3] // room pointer of dest
+
+	plan := corridorPlan{
+		rpf:  rpf,
+		rpt:  rpt,
+		del:  Coord{X: 0, Y: 1}, // direction of move
+		spos: rpf.Pos,           // start of move
+		epos: rpt.Pos,           // end of move
 	}
-	// Get ready to move...
-	curr := spos
+
+	if !rpf.Flags.Has(Gone) { // if not gone pick door pos
+		for {
+			plan.spos.X = rpf.Pos.X + g.rnd(rpf.Max.X-2) + 1
+
+			plan.spos.Y = rpf.Pos.Y + rpf.Max.Y - 1
+			if !rpf.Flags.Has(Maze) ||
+				g.Level.FlagsAt(plan.spos.Y, plan.spos.X).Has(FPassage) {
+				break
+			}
+		}
+	}
+
+	if !rpt.Flags.Has(Gone) {
+		for {
+			plan.epos.X = rpt.Pos.X + g.rnd(rpt.Max.X-2) + 1
+			if !rpt.Flags.Has(Maze) ||
+				g.Level.FlagsAt(plan.epos.Y, plan.epos.X).Has(FPassage) {
+				break
+			}
+		}
+	}
+
+	plan.distance = abs(plan.spos.Y-plan.epos.Y) - 1 // distance to move
+
+	plan.turnDelta.Y = 0 // direction to turn
+	if plan.spos.X < plan.epos.X {
+		plan.turnDelta.X = 1
+	} else {
+		plan.turnDelta.X = -1
+	}
+
+	plan.turnDistance = abs(plan.spos.X - plan.epos.X) // how far to turn
+
+	return plan
+}
+
+// connPlanRight sets up the movement variables for a corridor drawn to
+// the right (passages.c conn).
+func (g *RogueGame) connPlanRight(rm int) corridorPlan {
+	rpf := &g.Level.Rooms[rm]
+	rpt := &g.Level.Rooms[rm+1]
+
+	plan := corridorPlan{
+		rpf:  rpf,
+		rpt:  rpt,
+		del:  Coord{X: 1, Y: 0},
+		spos: rpf.Pos,
+		epos: rpt.Pos,
+	}
+
+	if !rpf.Flags.Has(Gone) {
+		for {
+			plan.spos.X = rpf.Pos.X + rpf.Max.X - 1
+
+			plan.spos.Y = rpf.Pos.Y + g.rnd(rpf.Max.Y-2) + 1
+			if !rpf.Flags.Has(Maze) ||
+				g.Level.FlagsAt(plan.spos.Y, plan.spos.X).Has(FPassage) {
+				break
+			}
+		}
+	}
+
+	if !rpt.Flags.Has(Gone) {
+		for {
+			plan.epos.Y = rpt.Pos.Y + g.rnd(rpt.Max.Y-2) + 1
+			if !rpt.Flags.Has(Maze) ||
+				g.Level.FlagsAt(plan.epos.Y, plan.epos.X).Has(FPassage) {
+				break
+			}
+		}
+	}
+
+	plan.distance = abs(plan.spos.X-plan.epos.X) - 1
+	if plan.spos.Y < plan.epos.Y {
+		plan.turnDelta.Y = 1
+	} else {
+		plan.turnDelta.Y = -1
+	}
+
+	plan.turnDelta.X = 0
+	plan.turnDistance = abs(plan.spos.Y - plan.epos.Y)
+
+	return plan
+}
+
+// connEnd draws a corridor end: a door on a real room, a passage square
+// on a gone one (passages.c conn).
+func (g *RogueGame) connEnd(rp *Room, pos Coord) {
+	if !rp.Flags.Has(Gone) {
+		g.door(rp, pos)
+	} else {
+		g.putPassage(pos)
+	}
+}
+
+// digCorridor digs from spos to epos, turning at turnSpot (the digging
+// loop of passages.c conn).
+func (g *RogueGame) digCorridor(plan corridorPlan, turnSpot int) {
+	curr := plan.spos
+	distance := plan.distance
+	turnDistance := plan.turnDistance
+
 	for distance > 0 {
 		// Move to new position
-		curr.X += del.X
-		curr.Y += del.Y
+		curr.X += plan.del.X
+		curr.Y += plan.del.Y
 		// Check if we are at the turn place, if so do the turn
 		if distance == turnSpot {
 			for ; turnDistance > 0; turnDistance-- {
-				g.putpass(curr)
-				curr.X += turnDelta.X
-				curr.Y += turnDelta.Y
+				g.putPassage(curr)
+				curr.X += plan.turnDelta.X
+				curr.Y += plan.turnDelta.Y
 			}
 		}
 		// Continue digging along
-		g.putpass(curr)
+		g.putPassage(curr)
+
 		distance--
 	}
-	curr.X += del.X
-	curr.Y += del.Y
-	if curr != epos {
+
+	curr.X += plan.del.X
+
+	curr.Y += plan.del.Y
+	if curr != plan.epos {
 		g.msg("warning, connectivity problem on this level")
 	}
 }
 
-// putpass adds a passage character or secret passage here (passages.c
+// putPassage adds a passage character or secret passage here (passages.c
 // putpass).
-func (g *RogueGame) putpass(cp Coord) {
+func (g *RogueGame) putPassage(cp Coord) {
 	pp := g.Level.At(cp.Y, cp.X)
-	pp.Flags.Set(FPass)
+	pp.Flags.Set(FPassage)
+
 	if g.rnd(10)+1 < g.Depth && g.rnd(40) == 0 {
 		pp.Flags.Clear(FReal)
 	} else {
@@ -229,7 +277,7 @@ func (g *RogueGame) putpass(cp Coord) {
 func (g *RogueGame) door(rm *Room, cp Coord) {
 	rm.Exits = append(rm.Exits, cp)
 
-	if rm.Flags.Has(IsMaze) {
+	if rm.Flags.Has(Maze) {
 		return
 	}
 
@@ -240,6 +288,7 @@ func (g *RogueGame) door(rm *Room, cp Coord) {
 		} else {
 			pp.Ch = '|'
 		}
+
 		pp.Flags.Clear(FReal)
 	} else {
 		pp.Ch = Door
@@ -250,79 +299,100 @@ func (g *RogueGame) door(rm *Room, cp Coord) {
 // (passages.c add_pass).
 func (g *RogueGame) addPass() {
 	for y := 1; y < NumLines-1; y++ {
-		for x := 0; x < NumCols; x++ {
-			pp := g.Level.At(y, x)
-			if pp.Flags.Has(FPass) || pp.Ch == Door ||
-				(!pp.Flags.Has(FReal) && (pp.Ch == '|' || pp.Ch == '-')) {
-				ch := pp.Ch
-				if pp.Flags.Has(FPass) {
-					ch = Passage
-				}
-				pp.Flags.Set(FSeen)
-				g.move(y, x)
-				if pp.Monst != nil {
-					pp.Monst.OldCh = pp.Ch
-				} else if pp.Flags.Has(FReal) {
-					g.addch(ch)
-				} else {
-					g.standout()
-					if pp.Flags.Has(FPass) {
-						g.addch(Passage)
-					} else {
-						g.addch(Door)
-					}
-					g.standend()
-				}
-			}
+		for x := range NumCols {
+			g.addPassSpot(g.Level.At(y, x), y, x)
 		}
 	}
 }
 
-// passnum assigns a number to each passageway (passages.c passnum).
-func (g *RogueGame) passnum() {
+// addPassSpot shows one passage or door square for the wizard (the loop
+// body of passages.c add_pass).
+func (g *RogueGame) addPassSpot(pp *Place, y, x int) {
+	if !pp.Flags.Has(FPassage) && !hiddenExit(pp.Flags, pp.Ch) {
+		return
+	}
+
+	ch := pp.Ch
+	if pp.Flags.Has(FPassage) {
+		ch = Passage
+	}
+
+	pp.Flags.Set(FSeen)
+	g.move(y, x)
+
+	switch {
+	case pp.Monst != nil:
+		pp.Monst.OldCh = pp.Ch
+	case pp.Flags.Has(FReal):
+		g.addch(ch)
+	default:
+		g.standout()
+
+		if pp.Flags.Has(FPassage) {
+			g.addch(Passage)
+		} else {
+			g.addch(Door)
+		}
+
+		g.standend()
+	}
+}
+
+// hiddenExit reports a door, or a secret door still drawn as a wall
+// (passages.c add_pass / numpass).
+func hiddenExit(fp PlaceFlags, ch byte) bool {
+	return ch == Door || (!fp.Has(FReal) && (ch == '|' || ch == '-'))
+}
+
+// numberPassages assigns a number to each passageway (passages.c passnum).
+func (g *RogueGame) numberPassages() {
 	g.pnum = 0
+
 	g.newpnum = false
 	for i := range g.Level.Passages {
 		g.Level.Passages[i].Exits = g.Level.Passages[i].Exits[:0]
 	}
+
 	for i := range g.Level.Rooms {
 		rp := &g.Level.Rooms[i]
 		for j := range rp.Exits {
 			g.newpnum = true
-			g.numpass(rp.Exits[j].Y, rp.Exits[j].X)
+			g.numberPassage(rp.Exits[j].Y, rp.Exits[j].X)
 		}
 	}
 }
 
-// numpass numbers a passageway square and its brethren (passages.c
+// numberPassage numbers a passageway square and its brethren (passages.c
 // numpass).
-func (g *RogueGame) numpass(y, x int) {
+func (g *RogueGame) numberPassage(y, x int) {
 	if x >= NumCols || x < 0 || y >= NumLines || y <= 0 {
 		return
 	}
+
 	fp := g.Level.FlagsAt(y, x)
-	if fp.Has(FPNum) {
+	if fp.Has(FPassNum) {
 		return
 	}
+
 	if g.newpnum {
 		g.pnum++
 		g.newpnum = false
 	}
 	// check to see if it is a door or secret door, i.e., a new exit, or a
 	// numerable type of place
-	if ch := g.Level.Char(y, x); ch == Door ||
-		(!fp.Has(FReal) && (ch == '|' || ch == '-')) {
+	if hiddenExit(*fp, g.Level.Char(y, x)) {
 		rp := &g.Level.Passages[g.pnum]
 		rp.Exits = append(rp.Exits, Coord{Y: y, X: x})
-	} else if !fp.Has(FPass) {
+	} else if !fp.Has(FPassage) {
 		return
 	}
-	*fp |= PlaceFlags(g.pnum)
+
+	*fp |= PlaceFlags(g.pnum) //nolint:gosec // G115: pnum < MaxPass=13
 	// recurse on the surrounding places
-	g.numpass(y+1, x)
-	g.numpass(y-1, x)
-	g.numpass(y, x+1)
-	g.numpass(y, x-1)
+	g.numberPassage(y+1, x)
+	g.numberPassage(y-1, x)
+	g.numberPassage(y, x+1)
+	g.numberPassage(y, x-1)
 }
 
 // abs is C abs() for ints.
@@ -330,5 +400,6 @@ func abs(n int) int {
 	if n < 0 {
 		return -n
 	}
+
 	return n
 }

game/potions.go

@@ -13,185 +13,233 @@ type pact struct {
 	straight string
 }
 
-// pActions is potions.c p_actions[]. The P_SEEINVIS message is dynamic
-// (it names the fruit) and is computed in doPot.
-var pActions = [MaxPotions]pact{
-	PConfuse: {IsHuh, DUnconfuse, HuhDuration,
-		"what a tripy feeling!",
-		"wait, what's going on here. Huh? What? Who?"},
-	PLSD: {IsHalu, DComeDown, SeeDuration,
-		"Oh, wow!  Everything seems so cosmic!",
-		"Oh, wow!  Everything seems so cosmic!"},
-	PSeeInvis: {CanSee, DUnsee, SeeDuration, "", ""},
-	PBlind: {IsBlind, DSight, SeeDuration,
-		"oh, bummer!  Everything is dark!  Help!",
-		"a cloak of darkness falls around you"},
-	PLevit: {IsLevit, DLand, HealTime,
-		"oh, wow!  You're floating in the air!",
-		"you start to float in the air"},
-}
-
 // quaff drinks a potion from the pack (potions.c quaff).
 func (g *RogueGame) quaff() {
 	p := &g.Player
-	obj := g.getItem("quaff", int(Potion))
+	obj, ok := g.promptPackItem("quaff", KindPotion)
 	// Make certain that it is something that we want to drink
-	if obj == nil {
+	if !ok {
 		return
 	}
-	if obj.Type != Potion {
+
+	if obj.Kind != KindPotion {
 		if !g.Options.Terse {
 			g.msg("yuk! Why would you want to drink that?")
 		} else {
 			g.msg("that's undrinkable")
 		}
+
 		return
 	}
+
 	if obj == p.CurWeapon {
 		p.CurWeapon = nil
 	}
 
 	// Calculate the effect it has on the poor guy.
-	trip := p.On(IsHalu)
+	trip := p.On(Hallucinating)
+
 	g.leavePack(obj, false, false)
-	switch obj.Which {
-	case PConfuse:
-		g.doPot(PConfuse, !trip)
-	case PPoison:
-		g.Items.Potions[PPoison].Know = true
-		if p.IsWearing(RSustStr) {
-			g.msg("you feel momentarily sick")
-		} else {
-			g.chgStr(-(g.rnd(3) + 1))
-			g.msg("you feel very sick now")
-			g.comeDown(0)
-		}
-	case PHealing:
-		g.Items.Potions[PHealing].Know = true
-		if p.Stats.HP += g.roll(p.Stats.Lvl, 4); p.Stats.HP > p.Stats.MaxHP {
-			p.Stats.MaxHP++
-			p.Stats.HP = p.Stats.MaxHP
-		}
-		g.sight(0)
-		g.msg("you begin to feel better")
-	case PStrength:
-		g.Items.Potions[PStrength].Know = true
-		g.chgStr(1)
-		g.msg("you feel stronger, now.  What bulging muscles!")
-	case PMFind:
-		p.Flags.Set(SeeMonst)
-		g.Fuse(DTurnSee, 1, HuhDuration, After)
-		if !g.turnSee(false) {
-			g.msg("you have a %s feeling for a moment, then it passes",
-				g.chooseStr("normal", "strange"))
-		}
-	case PTFind:
-		// Potion of magic detection.  Show the potions and scrolls
-		show := false
-		if len(g.Level.Objects) > 0 {
-			g.scr.Hw.Clear()
-			for _, tp := range g.Level.Objects {
-				if tp.isMagic() {
-					show = true
-					g.scr.Hw.MvAddCh(tp.Pos.Y, tp.Pos.X, Magic)
-					g.Items.Potions[PTFind].Know = true
-				}
-			}
-			for _, mp := range g.Level.Monsters {
-				for _, tp := range mp.Pack {
-					if tp.isMagic() {
-						show = true
-						g.scr.Hw.MvAddCh(mp.Pos.Y, mp.Pos.X, Magic)
-					}
-				}
-			}
-		}
-		if show {
-			g.Items.Potions[PTFind].Know = true
-			g.showWin("You sense the presence of magic on this level.--More--")
-		} else {
-			g.msg("you have a %s feeling for a moment, then it passes",
-				g.chooseStr("normal", "strange"))
-		}
-	case PLSD:
-		if !trip {
-			if p.On(SeeMonst) {
-				g.turnSee(false)
-			}
-			g.StartDaemon(DVisuals, 0, Before)
-			g.SeenStairs = g.seenStairs()
-		}
-		g.doPot(PLSD, true)
-	case PSeeInvis:
-		show := p.On(CanSee)
-		g.doPot(PSeeInvis, false)
-		if !show {
-			g.invisOn()
-		}
-		g.sight(0)
-	case PRaise:
-		g.Items.Potions[PRaise].Know = true
-		g.msg("you suddenly feel much more skillful")
-		g.raiseLevel()
-	case PXHeal:
-		g.Items.Potions[PXHeal].Know = true
-		if p.Stats.HP += g.roll(p.Stats.Lvl, 8); p.Stats.HP > p.Stats.MaxHP {
-			if p.Stats.HP > p.Stats.MaxHP+p.Stats.Lvl+1 {
-				p.Stats.MaxHP++
-			}
-			p.Stats.MaxHP++
-			p.Stats.HP = p.Stats.MaxHP
-		}
-		g.sight(0)
-		g.comeDown(0)
-		g.msg("you begin to feel much better")
-	case PHaste:
-		g.Items.Potions[PHaste].Know = true
-		g.After = false
-		if g.addHaste(true) {
-			g.msg("you feel yourself moving much faster")
-		}
-	case PRestore:
-		if p.IsRing(Left, RAddStr) {
-			addStr(&p.Stats.Str, -p.CurRing[Left].Arm)
-		}
-		if p.IsRing(Right, RAddStr) {
-			addStr(&p.Stats.Str, -p.CurRing[Right].Arm)
-		}
-		if p.Stats.Str < p.MaxStats.Str {
-			p.Stats.Str = p.MaxStats.Str
-		}
-		if p.IsRing(Left, RAddStr) {
-			addStr(&p.Stats.Str, p.CurRing[Left].Arm)
-		}
-		if p.IsRing(Right, RAddStr) {
-			addStr(&p.Stats.Str, p.CurRing[Right].Arm)
-		}
-		g.msg("hey, this tastes great.  It make you feel warm all over")
-	case PBlind:
-		g.doPot(PBlind, true)
-	case PLevit:
-		g.doPot(PLevit, true)
+
+	if h := g.data.quaffHandlers[obj.PotionKind()]; h != nil {
+		h(g, trip)
 	}
+
 	g.status()
 	// Throw the item away
 	g.callIt(&g.Items.Potions[obj.Which])
 }
 
+// The per-potion effect handlers, dispatched through
+// gameData.quaffHandlers. Each is one case of the C quaff switch.
+
+func (g *RogueGame) quaffConfusion(trip bool) {
+	g.applyPotionFuse(PotionConfusion, !trip)
+}
+
+func (g *RogueGame) quaffPoison(bool) {
+	g.Items.Potions[PotionPoison].Know = true
+	if g.Player.IsWearing(RingSustainStrength) {
+		g.msg("you feel momentarily sick")
+	} else {
+		g.changeStrength(-(g.rnd(3) + 1))
+		g.msg("you feel very sick now")
+		g.comeDown(0)
+	}
+}
+
+func (g *RogueGame) quaffHealing(bool) {
+	p := &g.Player
+
+	g.Items.Potions[PotionHealing].Know = true
+	if p.Stats.HP += g.roll(p.Stats.Lvl, 4); p.Stats.HP > p.Stats.MaxHP {
+		p.Stats.MaxHP++
+		p.Stats.HP = p.Stats.MaxHP
+	}
+
+	g.sight(0)
+	g.msg("you begin to feel better")
+}
+
+func (g *RogueGame) quaffGainStrength(bool) {
+	g.Items.Potions[PotionGainStrength].Know = true
+	g.changeStrength(1)
+	g.msg("you feel stronger, now.  What bulging muscles!")
+}
+
+func (g *RogueGame) quaffDetectMonsters(bool) {
+	g.Player.Flags.Set(SenseMonsters)
+	g.Fuse(DTurnSee, 1, HuhDuration, After)
+
+	if !g.turnSee(false) {
+		g.msg("you have a %s feeling for a moment, then it passes",
+			g.chooseStr("normal", "strange"))
+	}
+}
+
+func (g *RogueGame) quaffDetectMagic(bool) {
+	// Potion of magic detection.  Show the potions and scrolls
+	show := false
+
+	if len(g.Level.Objects) > 0 {
+		g.scr.Hw.Clear()
+
+		for _, tp := range g.Level.Objects {
+			if g.isMagic(tp) {
+				show = true
+
+				g.scr.Hw.MvAddCh(tp.Pos.Y, tp.Pos.X, Magic)
+				g.Items.Potions[PotionDetectMagic].Know = true
+			}
+		}
+
+		for _, mp := range g.Level.Monsters {
+			for _, tp := range mp.Pack {
+				if g.isMagic(tp) {
+					show = true
+
+					g.scr.Hw.MvAddCh(mp.Pos.Y, mp.Pos.X, Magic)
+				}
+			}
+		}
+	}
+
+	if show {
+		g.Items.Potions[PotionDetectMagic].Know = true
+		g.showWin("You sense the presence of magic on this level.--More--")
+	} else {
+		g.msg("you have a %s feeling for a moment, then it passes",
+			g.chooseStr("normal", "strange"))
+	}
+}
+
+func (g *RogueGame) quaffLSD(trip bool) {
+	p := &g.Player
+	if !trip {
+		if p.On(SenseMonsters) {
+			g.turnSee(false)
+		}
+
+		g.StartDaemon(DVisuals, 0, Before)
+		g.SeenStairs = g.seenStairs()
+	}
+
+	g.applyPotionFuse(PotionLSD, true)
+}
+
+func (g *RogueGame) quaffSeeInvisible(bool) {
+	show := g.Player.On(CanSeeInvisible)
+
+	g.applyPotionFuse(PotionSeeInvisible, false)
+
+	if !show {
+		g.invisOn()
+	}
+
+	g.sight(0)
+}
+
+func (g *RogueGame) quaffRaiseLevel(bool) {
+	g.Items.Potions[PotionRaiseLevel].Know = true
+	g.msg("you suddenly feel much more skillful")
+	g.raiseLevel()
+}
+
+func (g *RogueGame) quaffExtraHealing(bool) {
+	p := &g.Player
+
+	g.Items.Potions[PotionExtraHealing].Know = true
+	if p.Stats.HP += g.roll(p.Stats.Lvl, 8); p.Stats.HP > p.Stats.MaxHP {
+		if p.Stats.HP > p.Stats.MaxHP+p.Stats.Lvl+1 {
+			p.Stats.MaxHP++
+		}
+
+		p.Stats.MaxHP++
+		p.Stats.HP = p.Stats.MaxHP
+	}
+
+	g.sight(0)
+	g.comeDown(0)
+	g.msg("you begin to feel much better")
+}
+
+func (g *RogueGame) quaffHaste(bool) {
+	g.Items.Potions[PotionHaste].Know = true
+
+	g.After = false
+	if g.addHaste(true) {
+		g.msg("you feel yourself moving much faster")
+	}
+}
+
+func (g *RogueGame) quaffRestoreStrength(bool) {
+	p := &g.Player
+	if p.IsRing(Left, RingAddStrength) {
+		addStr(&p.Stats.Str, -p.CurRing[Left].Bonus)
+	}
+
+	if p.IsRing(Right, RingAddStrength) {
+		addStr(&p.Stats.Str, -p.CurRing[Right].Bonus)
+	}
+
+	if p.Stats.Str < p.MaxStats.Str {
+		p.Stats.Str = p.MaxStats.Str
+	}
+
+	if p.IsRing(Left, RingAddStrength) {
+		addStr(&p.Stats.Str, p.CurRing[Left].Bonus)
+	}
+
+	if p.IsRing(Right, RingAddStrength) {
+		addStr(&p.Stats.Str, p.CurRing[Right].Bonus)
+	}
+
+	g.msg("hey, this tastes great.  It make you feel warm all over")
+}
+
+func (g *RogueGame) quaffBlindness(bool) {
+	g.applyPotionFuse(PotionBlindness, true)
+}
+
+func (g *RogueGame) quaffLevitation(bool) {
+	g.applyPotionFuse(PotionLevitation, true)
+}
+
 // raiseLevel: the guy just magically went up a level (potions.c
 // raise_level).
 func (g *RogueGame) raiseLevel() {
-	g.Player.Stats.Exp = eLevels[g.Player.Stats.Lvl-1] + 1
+	g.Player.Stats.Exp = g.data.eLevels[g.Player.Stats.Lvl-1] + 1
 	g.checkLevel()
 }
 
-// doPot does a potion with standard setup: it uses a fuse and turns on a
-// flag (potions.c do_pot).
-func (g *RogueGame) doPot(typ int, knowit bool) {
-	pp := &pActions[typ]
-	if !g.Items.Potions[typ].Know {
-		g.Items.Potions[typ].Know = knowit
+// applyPotionFuse does a potion with standard setup: it uses a fuse and
+// turns on a flag (potions.c do_pot).
+func (g *RogueGame) applyPotionFuse(kind PotionKind, knowit bool) {
+	pp := &g.data.pActions[kind]
+	if !g.Items.Potions[kind].Know {
+		g.Items.Potions[kind].Know = knowit
 	}
+
 	t := g.spread(pp.time)
 	if !g.Player.On(pp.flags) {
 		g.Player.Flags.Set(pp.flags)
@@ -200,33 +248,38 @@ func (g *RogueGame) doPot(typ int, knowit bool) {
 	} else {
 		g.Lengthen(pp.daemon, t)
 	}
+
 	high, straight := pp.high, pp.straight
-	if typ == PSeeInvis {
+
+	if kind == PotionSeeInvisible {
 		s := fmt.Sprintf("this potion tastes like %s juice", g.Fruit)
 		high, straight = s, s
 	}
+
 	g.msg("%s", g.chooseStr(high, straight))
 }
 
 // isMagic reports whether an object radiates magic (potions.c is_magic).
-func (o *Object) isMagic() bool {
-	switch o.Type {
-	case Armor:
-		return o.Flags.Has(IsProt) || o.Arm != aClass[o.Which]
-	case Weapon:
+func (g *RogueGame) isMagic(o *Object) bool {
+	switch o.Kind {
+	case KindArmor:
+		return o.Flags.Has(Protected) || o.ArmorClass != g.data.aClass[o.Which]
+	case KindWeapon:
 		return o.HPlus != 0 || o.DPlus != 0
-	case Potion, Scroll, Stick, Ring, Amulet:
+	case KindPotion, KindScroll, KindWand, KindRing, KindAmulet:
 		return true
 	}
+
 	return false
 }
 
 // invisOn turns on the ability to see invisible monsters (potions.c
 // invis_on).
 func (g *RogueGame) invisOn() {
-	g.Player.Flags.Set(CanSee)
+	g.Player.Flags.Set(CanSeeInvisible)
+
 	for _, mp := range g.Level.Monsters {
-		if mp.On(IsInvis) && g.seeMonst(mp) && !g.Player.On(IsHalu) {
+		if mp.On(Invisible) && g.seeMonst(mp) && !g.Player.On(Hallucinating) {
 			g.mvaddch(mp.Pos.Y, mp.Pos.X, mp.Disguise)
 		}
 	}
@@ -236,55 +289,75 @@ func (g *RogueGame) invisOn() {
 // turn_see).
 func (g *RogueGame) turnSee(turnOff bool) bool {
 	addNew := false
+
 	for _, mp := range g.Level.Monsters {
 		g.move(mp.Pos.Y, mp.Pos.X)
+
 		canSee := g.seeMonst(mp)
 		if turnOff {
 			if !canSee {
 				g.addch(mp.OldCh)
 			}
-		} else {
-			if !canSee {
-				g.standout()
-			}
-			if !g.Player.On(IsHalu) {
-				g.addch(mp.Type)
-			} else {
-				g.addch(byte(g.rnd(26) + 'A'))
-			}
-			if !canSee {
-				g.standend()
-				addNew = true
-			}
+		} else if g.showSensed(mp, canSee) {
+			addNew = true
 		}
 	}
+
 	if turnOff {
-		g.Player.Flags.Clear(SeeMonst)
+		g.Player.Flags.Clear(SenseMonsters)
 	} else {
-		g.Player.Flags.Set(SeeMonst)
+		g.Player.Flags.Set(SenseMonsters)
 	}
+
 	return addNew
 }
 
+// showSensed draws one monster for monster sense, standout when it is
+// otherwise invisible; it reports whether the monster was newly revealed
+// (the turn-on arm of the C turn_see loop).
+func (g *RogueGame) showSensed(mp *Monster, canSee bool) bool {
+	if !canSee {
+		g.standout()
+	}
+
+	if !g.Player.On(Hallucinating) {
+		g.addch(mp.Type)
+	} else {
+		g.addch(g.randomMonsterLetter())
+	}
+
+	if !canSee {
+		g.standend()
+
+		return true
+	}
+
+	return false
+}
+
 // seenStairs reports whether the player has seen the stairs (potions.c
 // seen_stairs).
 func (g *RogueGame) seenStairs() bool {
 	st := g.Level.Stairs
 	g.move(st.Y, st.X)
+
 	if g.inch() == Stairs { // it's on the map
 		return true
 	}
+
 	if g.Player.Pos == st { // it's under him
 		return true
 	}
 	// if a monster is on the stairs, this gets hairy
 	if tp := g.Level.MonsterAt(st.Y, st.X); tp != nil {
-		if g.seeMonst(tp) && tp.On(IsRun) { // visible and awake:
+		if g.seeMonst(tp) && tp.On(Awake) { // visible and awake:
 			return true // it must have moved there
 		}
-		if g.Player.On(SeeMonst) && tp.OldCh == Stairs {
+
+		if g.Player.On(SenseMonsters) && tp.OldCh == Stairs {
 			return true
 		}
 	}
+
 	return false
 }

game/rings.go

@@ -7,17 +7,16 @@ import "fmt"
 // ringOn puts a ring on a hand (rings.c ring_on).
 func (g *RogueGame) ringOn() {
 	p := &g.Player
-	obj := g.getItem("put on", int(Ring))
+	obj, ok := g.promptPackItem("put on", KindRing)
 	// Make certain that it is something that we want to wear
-	if obj == nil {
+	if !ok {
 		return
 	}
-	if obj.Type != Ring {
-		if !g.Options.Terse {
-			g.msg("it would be difficult to wrap that around a finger")
-		} else {
-			g.msg("not a ring")
-		}
+
+	if obj.Kind != KindRing {
+		g.msg("%s", g.chooseTerse("not a ring",
+			"it would be difficult to wrap that around a finger"))
+
 		return
 	}
 
@@ -26,46 +25,56 @@ func (g *RogueGame) ringOn() {
 		return
 	}
 
-	var ring int
-	switch {
-	case p.CurRing[Left] == nil && p.CurRing[Right] == nil:
-		if ring = g.gethand(); ring < 0 {
-			return
-		}
-	case p.CurRing[Left] == nil:
-		ring = Left
-	case p.CurRing[Right] == nil:
-		ring = Right
-	default:
-		if !g.Options.Terse {
-			g.msg("you already have a ring on each hand")
-		} else {
-			g.msg("wearing two")
-		}
+	ring := g.pickRingHand()
+	if ring < 0 {
 		return
 	}
+
 	p.CurRing[ring] = obj
 
 	// Calculate the effect it has on the poor guy.
-	switch obj.Which {
-	case RAddStr:
-		g.chgStr(obj.Arm)
-	case RSeeInvis:
+	switch obj.RingKind() {
+	case RingAddStrength:
+		g.changeStrength(obj.Bonus)
+	case RingSeeInvisible:
 		g.invisOn()
-	case RAggr:
+	case RingAggravateMonsters:
 		g.aggravate()
 	}
 
 	if !g.Options.Terse {
-		g.addmsg("you are now wearing ")
+		g.addmsgf("you are now wearing ")
+	}
+
+	g.msg("%s (%c)", g.inventoryName(obj, true), obj.PackCh)
+}
+
+// pickRingHand chooses the hand for a new ring, asking when both are
+// free; negative aborts (rings.c ring_on).
+func (g *RogueGame) pickRingHand() int {
+	p := &g.Player
+
+	switch {
+	case p.CurRing[Left] == nil && p.CurRing[Right] == nil:
+		return g.gethand()
+	case p.CurRing[Left] == nil:
+		return Left
+	case p.CurRing[Right] == nil:
+		return Right
+	default:
+		g.msg("%s", g.chooseTerse("wearing two",
+			"you already have a ring on each hand"))
+
+		return -1
 	}
-	g.msg("%s (%c)", g.invName(obj, true), obj.PackCh)
 }
 
 // ringOff takes off a ring (rings.c ring_off).
 func (g *RogueGame) ringOff() {
 	p := &g.Player
+
 	var ring int
+
 	switch {
 	case p.CurRing[Left] == nil && p.CurRing[Right] == nil:
 		if g.Options.Terse {
@@ -73,6 +82,7 @@ func (g *RogueGame) ringOff() {
 		} else {
 			g.msg("you aren't wearing any rings")
 		}
+
 		return
 	case p.CurRing[Left] == nil:
 		ring = Right
@@ -83,14 +93,18 @@ func (g *RogueGame) ringOff() {
 			return
 		}
 	}
+
 	g.Msgs.Mpos = 0
+
 	obj := p.CurRing[ring]
 	if obj == nil {
 		g.msg("not wearing such a ring")
+
 		return
 	}
+
 	if g.dropCheck(obj) {
-		g.msg("was wearing %s(%c)", g.invName(obj, true), obj.PackCh)
+		g.msg("was wearing %s(%c)", g.inventoryName(obj, true), obj.PackCh)
 	}
 }
 
@@ -102,17 +116,22 @@ func (g *RogueGame) gethand() int {
 		} else {
 			g.msg("left hand or right hand? ")
 		}
+
 		c := g.readchar()
 		if c == Escape {
 			return -1
 		}
+
 		g.Msgs.Mpos = 0
+
 		if c == 'l' || c == 'L' {
 			return Left
 		}
+
 		if c == 'r' || c == 'R' {
 			return Right
 		}
+
 		if g.Options.Terse {
 			g.msg("L or R")
 		} else {
@@ -121,25 +140,6 @@ func (g *RogueGame) gethand() int {
 	}
 }
 
-// ringUses is the rings.c ring_eat static uses[] table: how much food each
-// ring type uses up per turn (negative = a 1-in-n chance of 1).
-var ringUses = [MaxRings]int{
-	1,  // R_PROTECT
-	1,  // R_ADDSTR
-	1,  // R_SUSTSTR
-	-3, // R_SEARCH
-	-5, // R_SEEINVIS
-	0,  // R_NOP
-	0,  // R_AGGR
-	-3, // R_ADDHIT
-	-3, // R_ADDDAM
-	2,  // R_REGEN
-	-2, // R_DIGEST
-	0,  // R_TELEPORT
-	1,  // R_STEALTH
-	1,  // R_SUSTARM
-}
-
 // ringEat reports how much food the ring on the given hand uses up
 // (rings.c ring_eat).
 func (g *RogueGame) ringEat(hand int) int {
@@ -147,7 +147,8 @@ func (g *RogueGame) ringEat(hand int) int {
 	if ring == nil {
 		return 0
 	}
-	eat := ringUses[ring.Which]
+
+	eat := g.data.ringUses[ring.RingKind()]
 	if eat < 0 {
 		if g.rnd(-eat) == 0 {
 			eat = 1
@@ -155,20 +156,25 @@ func (g *RogueGame) ringEat(hand int) int {
 			eat = 0
 		}
 	}
-	if ring.Which == RDigest {
+
+	if ring.RingKind() == RingSlowDigestion {
 		eat = -eat
 	}
+
 	return eat
 }
 
-// ringNum prints ring bonuses (rings.c ring_num).
-func ringNum(g *RogueGame, obj *Object) string {
-	if !obj.Flags.Has(IsKnow) {
+// ringNum prints ring bonuses (rings.c ring_num). The unused game
+// parameter keeps the nameit prfunc signature.
+func ringNum(_ *RogueGame, obj *Object) string {
+	if !obj.Flags.Has(Known) {
 		return ""
 	}
-	switch obj.Which {
-	case RProtect, RAddStr, RAddDam, RAddHit:
-		return fmt.Sprintf(" [%s]", num(obj.Arm, 0, Ring))
+
+	switch obj.RingKind() {
+	case RingProtection, RingAddStrength, RingIncreaseDamage, RingDexterity:
+		return fmt.Sprintf(" [%s]", num(obj.Bonus, 0, Ring))
 	}
+
 	return ""
 }

game/rip.go

@@ -2,76 +2,71 @@ package game
 
 import (
 	"fmt"
+	"os"
 	"time"
 )
 
 // rip.c — the fun ends: death or a total win.
 //
-// The C functions here call exit(); the port panics with a gameEnd sentinel
-// that Run recovers, so the terminal is restored by normal unwinding.
+// The C functions here call exit(). One game run is one process, so the
+// port does the same: myExit restores the terminal and exits directly.
 
-// gameEnd is the sentinel carried by the panic that replaces my_exit().
-type gameEnd struct{ status int }
-
-// myExit leaves the process properly (main.c my_exit): it unwinds to Run.
-func (g *RogueGame) myExit(st int) {
-	g.Playing = false
-	panic(gameEnd{status: st})
-}
-
-var ripArt = []string{
-	"                       __________",
-	"                      /          \\",
-	"                     /    REST    \\",
-	"                    /      IN      \\",
-	"                   /     PEACE      \\",
-	"                  /                  \\",
-	"                  |                  |",
-	"                  |                  |",
-	"                  |   killed by a    |",
-	"                  |                  |",
-	"                  |       1980       |",
-	"                 *|     *  *  *      | *",
-	"         ________)/\\\\_//(\\/(/\\)/\\//\\/|_)_______",
+// myExit leaves the process properly (main.c my_exit): it restores the
+// terminal and ends the process. Every C caller exited with status 0.
+func (g *RogueGame) myExit() {
+	g.scr.Fini()
+	os.Exit(0)
 }
 
 // death does something really fun when he dies (rip.c death).
 func (g *RogueGame) death(monst byte) {
 	p := &g.Player
 	p.Purse -= p.Purse / 10
+
 	g.clear()
+
 	killer := g.killname(monst, false)
 	if !g.Options.Tombstone {
-		g.scr.Std.MvPrintw(NumLines-2, 0, "Killed by ")
+		g.scr.Std.MvPrintwf(NumLines-2, 0, "Killed by ")
+
 		if monst != 's' && monst != 'h' {
 			g.printw("a%s ", vowelstr(killer))
 		}
+
 		g.printw("%s with %d gold", killer, p.Purse)
 	} else {
 		year := time.Now().Year()
-		for i, line := range ripArt {
+
+		for i, line := range g.data.ripArt {
 			g.scr.Std.MvAddStr(8+i, 0, line)
 		}
+
 		g.mvaddstr(17, center(killer), killer)
+
 		if monst == 's' || monst == 'h' {
 			g.mvaddch(16, 32, ' ')
 		} else {
 			g.mvaddstr(16, 33, vowelstr(killer))
 		}
+
 		g.mvaddstr(14, center(g.Whoami), g.Whoami)
+
 		au := fmt.Sprintf("%d Au", p.Purse)
 		g.mvaddstr(15, center(au), au)
 		g.mvaddstr(18, 26, fmt.Sprintf("%4d", year))
 	}
+
 	g.mvaddstr(NumLines-1, 0, "[Press return to continue]")
 	g.refresh()
+
 	flags := 0
 	if g.HasAmulet {
 		flags = 3
 	}
+
 	g.score(p.Purse, flags, monst)
 	g.waitFor('\n')
-	g.myExit(0)
+	g.myExit()
 }
 
 // center returns the column to center the given string on the tombstone
@@ -85,6 +80,7 @@ func (g *RogueGame) totalWinner() {
 	p := &g.Player
 	g.clear()
 	g.standout()
+
 	banner := []string{
 		"                                                               ",
 		"  @   @               @   @           @          @@@  @     @  ",
@@ -100,6 +96,7 @@ func (g *RogueGame) totalWinner() {
 	for i, line := range banner {
 		g.scr.Std.MvAddStr(i, 0, line)
 	}
+
 	g.standend()
 	g.scr.Std.MvAddStr(10, 0, "You have joined the elite ranks of those who have escaped the")
 	g.scr.Std.MvAddStr(11, 0, "Dungeons of Doom alive.  You journey home and sell all your loot at")
@@ -110,127 +107,159 @@ func (g *RogueGame) totalWinner() {
 	g.clear()
 	g.mvaddstr(0, 0, "   Worth  Item")
 	g.move(1, 0)
+
 	oldpurse := p.Purse
 	line := 1
+
 	for _, obj := range p.Pack {
-		worth := 0
-		it := &g.Items
-		switch obj.Type {
-		case Food:
-			worth = 2 * obj.Count
-		case Weapon:
-			worth = it.Weapons[obj.Which].Worth
-			worth *= 3*(obj.HPlus+obj.DPlus) + obj.Count
-			obj.Flags.Set(IsKnow)
-		case Armor:
-			worth = it.Armors[obj.Which].Worth
-			worth += (9 - obj.Arm) * 100
-			worth += 10 * (aClass[obj.Which] - obj.Arm)
-			obj.Flags.Set(IsKnow)
-		case Scroll:
-			op := &it.Scrolls[obj.Which]
-			worth = op.Worth * obj.Count
-			if !op.Know {
-				worth /= 2
-			}
-			op.Know = true
-		case Potion:
-			op := &it.Potions[obj.Which]
-			worth = op.Worth * obj.Count
-			if !op.Know {
-				worth /= 2
-			}
-			op.Know = true
-		case Ring:
-			op := &it.Rings[obj.Which]
-			worth = op.Worth
-			if obj.Which == RAddStr || obj.Which == RAddDam ||
-				obj.Which == RProtect || obj.Which == RAddHit {
-				if obj.Arm > 0 {
-					worth += obj.Arm * 100
-				} else {
-					worth = 10
-				}
-			}
-			if !obj.Flags.Has(IsKnow) {
-				worth /= 2
-			}
-			obj.Flags.Set(IsKnow)
-			op.Know = true
-		case Stick:
-			op := &it.Sticks[obj.Which]
-			worth = op.Worth
-			worth += 20 * obj.Charges()
-			if !obj.Flags.Has(IsKnow) {
-				worth /= 2
-			}
-			obj.Flags.Set(IsKnow)
-			op.Know = true
-		case Amulet:
-			worth = 1000
-		}
-		if worth < 0 {
-			worth = 0
-		}
-		g.scr.Std.MvPrintw(line, 0, "%c) %5d  %s", obj.PackCh, worth,
-			g.invName(obj, false))
+		worth := g.objectWorth(obj)
+
+		g.scr.Std.MvPrintwf(line, 0, "%c) %5d  %s", obj.PackCh, worth,
+			g.inventoryName(obj, false))
 		line++
 		p.Purse += worth
 	}
-	g.scr.Std.MvPrintw(line, 0, "   %5d  Gold Pieces          ", oldpurse)
+
+	g.scr.Std.MvPrintwf(line, 0, "   %5d  Gold Pieces          ", oldpurse)
 	g.refresh()
 	g.score(p.Purse, 2, ' ')
-	g.myExit(0)
+	g.myExit()
 }
 
-// killnameTable is the rip.c nlist[]: special death causes.
-var killnameTable = []helpEntry{
-	{'a', "arrow", true},
-	{'b', "bolt", true},
-	{'d', "dart", true},
-	{'h', "hypothermia", false},
-	{'s', "starvation", false},
+// objectWorth appraises one pack item on the way out, marking it known
+// (the switch of rip.c total_winner).
+func (g *RogueGame) objectWorth(obj *Object) int {
+	it := &g.Items
+	worth := 0
+
+	switch obj.Kind {
+	case KindFood:
+		worth = 2 * obj.Count
+	case KindWeapon:
+		worth = it.Weapons[obj.Which].Worth
+		worth *= 3*(obj.HPlus+obj.DPlus) + obj.Count
+		obj.Flags.Set(Known)
+	case KindArmor:
+		worth = it.Armors[obj.Which].Worth
+		worth += (9 - obj.ArmorClass) * 100
+		worth += 10 * (g.data.aClass[obj.Which] - obj.ArmorClass)
+		obj.Flags.Set(Known)
+	case KindScroll:
+		worth = loreWorth(&it.Scrolls[obj.Which], obj.Count)
+	case KindPotion:
+		worth = loreWorth(&it.Potions[obj.Which], obj.Count)
+	case KindRing:
+		worth = g.ringWorth(obj)
+	case KindWand:
+		worth = g.wandWorth(obj)
+	case KindAmulet:
+		worth = 1000
+	}
+
+	if worth < 0 {
+		worth = 0
+	}
+
+	return worth
+}
+
+// loreWorth appraises a scroll or potion, halved when unidentified, and
+// identifies it (rip.c total_winner).
+func loreWorth(op *ObjInfo, count int) int {
+	worth := op.Worth * count
+	if !op.Know {
+		worth /= 2
+	}
+
+	op.Know = true
+
+	return worth
+}
+
+// ringWorth appraises a ring: bonus rings gain by their bonus, cursed
+// ones are junk (rip.c total_winner).
+func (g *RogueGame) ringWorth(obj *Object) int {
+	op := &g.Items.Rings[obj.Which]
+	worth := op.Worth
+
+	if obj.RingKind() == RingAddStrength || obj.RingKind() == RingIncreaseDamage ||
+		obj.RingKind() == RingProtection || obj.RingKind() == RingDexterity {
+		if obj.Bonus > 0 {
+			worth += obj.Bonus * 100
+		} else {
+			worth = 10
+		}
+	}
+
+	if !obj.Flags.Has(Known) {
+		worth /= 2
+	}
+
+	obj.Flags.Set(Known)
+
+	op.Know = true
+
+	return worth
+}
+
+// wandWorth appraises a wand or staff by its charges (rip.c
+// total_winner).
+func (g *RogueGame) wandWorth(obj *Object) int {
+	op := &g.Items.Sticks[obj.Which]
+	worth := op.Worth
+
+	worth += 20 * obj.Charges
+	if !obj.Flags.Has(Known) {
+		worth /= 2
+	}
+
+	obj.Flags.Set(Known)
+
+	op.Know = true
+
+	return worth
 }
 
 // killname converts a code to a monster name (rip.c killname).
 func (g *RogueGame) killname(monst byte, doart bool) string {
-	var sp string
-	var article bool
+	var (
+		sp      string
+		article bool
+	)
+
 	if isUpper(monst) {
 		sp = g.Monsters[monst-'A'].Name
 		article = true
 	} else {
 		sp = "Wally the Wonder Badger"
 		article = false
-		for _, hp := range killnameTable {
+
+		for _, hp := range g.data.killnameTable {
 			if hp.Ch == monst {
 				sp = hp.Desc
 				article = hp.Print
+
 				break
 			}
 		}
 	}
+
 	if doart && article {
 		return "a" + vowelstr(sp) + " " + sp
 	}
+
 	return sp
 }
 
 // DeathDemo implements the -d command line option (main.c): burn some
-// random numbers to break patterns, then die a random death.
+// random numbers to break patterns, then die a random death. It does not
+// return — death exits the process.
 func (g *RogueGame) DeathDemo() {
-	defer func() {
-		if r := recover(); r != nil {
-			if _, ok := r.(gameEnd); ok {
-				return
-			}
-			panic(r)
-		}
-	}()
 	dnum := g.rnd(100)
 	for dnum--; dnum > 0; dnum-- {
 		g.rnd(100)
 	}
+
 	g.Player.Purse = g.rnd(100) + 1
 	g.Depth = g.rnd(100) + 1
 	g.death(g.deathMonst())
@@ -245,5 +274,6 @@ func (g *RogueGame) deathMonst() byte {
 		'Y', 'Z', 'a', 'b', 'h', 'd', 's',
 		' ', // generates the "Wally the Wonder Badger" message
 	}
+
 	return poss[g.rnd(len(poss))]
 }

game/rng.go

@@ -11,21 +11,17 @@ type Rng struct {
 	Seed int32
 }
 
-// next steps the generator and returns the next raw value (the RN macro).
-func (r *Rng) next() int {
-	r.Seed = r.Seed*11109 + 13849
-	return int(r.Seed>>16) & 0xffff
-}
-
 // Rnd picks a very random number in [0, rng) (main.c rnd).
 func (r *Rng) Rnd(rng int) int {
 	if rng == 0 {
 		return 0
 	}
+
 	v := r.next()
 	if v < 0 {
 		v = -v
 	}
+
 	return v % rng
 }
 
@@ -35,9 +31,17 @@ func (r *Rng) Roll(number, sides int) int {
 	for ; number > 0; number-- {
 		dtotal += r.Rnd(sides) + 1
 	}
+
 	return dtotal
 }
 
+// next steps the generator and returns the next raw value (the RN macro).
+func (r *Rng) next() int {
+	r.Seed = r.Seed*11109 + 13849
+
+	return int(r.Seed>>16) & 0xffff
+}
+
 // rnd is the ported code's spelling of C rnd(): every call site in the C
 // sources reads rnd(x), and keeping that shape makes cross-checking easy.
 func (g *RogueGame) rnd(rng int) int { return g.Rng.Rnd(rng) }

game/rng_test.go

@@ -46,6 +46,7 @@ func TestRndZeroDoesNotStep(t *testing.T) {
 	if got := r.Rnd(0); got != 0 {
 		t.Fatalf("rnd(0) = %d, want 0", got)
 	}
+
 	if r.Seed != 42 {
 		t.Fatalf("rnd(0) stepped the generator: seed = %d, want 42", r.Seed)
 	}
@@ -58,6 +59,7 @@ func TestSpreadSmallValues(t *testing.T) {
 	if got := g.spread(1); got != 1 {
 		t.Errorf("spread(1) = %d, want 1", got)
 	}
+
 	if got := g.spread(2); got != 2 {
 		t.Errorf("spread(2) = %d, want 2", got)
 	}

game/rooms.go

@@ -17,10 +17,11 @@ type mazeState struct {
 
 const goldGrp = 1
 
-// doRooms creates rooms and corridors with a connectivity graph (rooms.c
+// digRooms creates rooms and corridors with a connectivity graph (rooms.c
 // do_rooms).
-func (g *RogueGame) doRooms() {
+func (g *RogueGame) digRooms() {
 	var bsze Coord // maximum room size
+
 	bsze.X = NumCols / 3
 	bsze.Y = NumLines / 3
 	// Clear things for a new level
@@ -32,92 +33,136 @@ func (g *RogueGame) doRooms() {
 	}
 	// Put the gone rooms, if any, on the level
 	leftOut := g.rnd(4)
-	for i := 0; i < leftOut; i++ {
-		g.Level.Rooms[g.rndRoom()].Flags.Set(IsGone)
+	for range leftOut {
+		g.Level.Rooms[g.randomRoom()].Flags.Set(Gone)
 	}
 	// dig and populate all the rooms on the level
 	for i := range g.Level.Rooms {
-		rp := &g.Level.Rooms[i]
-		// Find upper left corner of box that this room goes in
-		top := Coord{X: (i%3)*bsze.X + 1, Y: (i / 3) * bsze.Y}
-		if rp.Flags.Has(IsGone) {
-			// Place a gone room.  Make certain that there is a blank line
-			// for passage drawing.
-			for {
-				rp.Pos.X = top.X + g.rnd(bsze.X-2) + 1
-				rp.Pos.Y = top.Y + g.rnd(bsze.Y-2) + 1
-				rp.Max.X = -NumCols
-				rp.Max.Y = -NumLines
-				if rp.Pos.Y > 0 && rp.Pos.Y < NumLines-1 {
-					break
-				}
-			}
-			continue
+		g.digRoom(i, bsze)
+	}
+}
+
+// digRoom digs and populates one room (the loop body of rooms.c
+// do_rooms).
+func (g *RogueGame) digRoom(i int, bsze Coord) {
+	rp := &g.Level.Rooms[i]
+	// Find upper left corner of box that this room goes in
+	top := Coord{X: (i%3)*bsze.X + 1, Y: (i / 3) * bsze.Y}
+
+	if rp.Flags.Has(Gone) {
+		g.placeGoneRoom(rp, top, bsze)
+
+		return
+	}
+	// set room type
+	if g.rnd(10) < g.Depth-1 {
+		rp.Flags.Set(Dark) // dark room
+
+		if g.rnd(15) == 0 {
+			rp.Flags = Maze // maze room
 		}
-		// set room type
-		if g.rnd(10) < g.Depth-1 {
-			rp.Flags.Set(IsDark) // dark room
-			if g.rnd(15) == 0 {
-				rp.Flags = IsMaze // maze room
-			}
+	}
+	// Find a place and size for a random room
+	if rp.Flags.Has(Maze) {
+		placeMazeRoom(rp, top, bsze)
+	} else {
+		g.placeNormalRoom(rp, top, bsze)
+	}
+
+	g.drawRoom(rp)
+	g.roomGold(rp)
+	g.roomMonster(rp)
+}
+
+// placeGoneRoom places a gone room, making certain that there is a
+// blank line for passage drawing (rooms.c do_rooms).
+func (g *RogueGame) placeGoneRoom(rp *Room, top, bsze Coord) {
+	for {
+		rp.Pos.X = top.X + g.rnd(bsze.X-2) + 1
+		rp.Pos.Y = top.Y + g.rnd(bsze.Y-2) + 1
+		rp.Max.X = -NumCols
+
+		rp.Max.Y = -NumLines
+		if rp.Pos.Y > 0 && rp.Pos.Y < NumLines-1 {
+			return
 		}
-		// Find a place and size for a random room
-		if rp.Flags.Has(IsMaze) {
-			rp.Max.X = bsze.X - 1
-			rp.Max.Y = bsze.Y - 1
-			if rp.Pos.X = top.X; rp.Pos.X == 1 {
-				rp.Pos.X = 0
-			}
-			if rp.Pos.Y = top.Y; rp.Pos.Y == 0 {
-				rp.Pos.Y++
-				rp.Max.Y--
-			}
-		} else {
-			for {
-				rp.Max.X = g.rnd(bsze.X-4) + 4
-				rp.Max.Y = g.rnd(bsze.Y-4) + 4
-				rp.Pos.X = top.X + g.rnd(bsze.X-rp.Max.X)
-				rp.Pos.Y = top.Y + g.rnd(bsze.Y-rp.Max.Y)
-				if rp.Pos.Y != 0 {
-					break
-				}
-			}
-		}
-		g.drawRoom(rp)
-		// Put the gold in
-		if g.rnd(2) == 0 && (!g.HasAmulet || g.Depth >= g.MaxDepth) {
-			gold := newObject()
-			rp.GoldVal = g.goldCalc()
-			gold.SetGoldVal(rp.GoldVal)
-			rp.Gold, _ = g.findFloorIn(rp, 0, false)
-			gold.Pos = rp.Gold
-			g.Level.SetChar(rp.Gold.Y, rp.Gold.X, Gold)
-			gold.Flags = IsMany
-			gold.Group = goldGrp
-			gold.Type = Gold
-			attachObj(&g.Level.Objects, gold)
-		}
-		// Put the monster in
-		prob := 25
-		if rp.GoldVal > 0 {
-			prob = 80
-		}
-		if g.rnd(100) < prob {
-			tp := &Monster{}
-			mp, _ := g.findFloorIn(rp, 0, true)
-			g.newMonster(tp, g.randMonster(false), mp)
-			g.givePack(tp)
+	}
+}
+
+// placeMazeRoom sizes a maze room to fill its box (rooms.c do_rooms).
+func placeMazeRoom(rp *Room, top, bsze Coord) {
+	rp.Max.X = bsze.X - 1
+
+	rp.Max.Y = bsze.Y - 1
+	if rp.Pos.X = top.X; rp.Pos.X == 1 {
+		rp.Pos.X = 0
+	}
+
+	if rp.Pos.Y = top.Y; rp.Pos.Y == 0 {
+		rp.Pos.Y++
+		rp.Max.Y--
+	}
+}
+
+// placeNormalRoom rolls a place and size for an ordinary room (rooms.c
+// do_rooms).
+func (g *RogueGame) placeNormalRoom(rp *Room, top, bsze Coord) {
+	for {
+		rp.Max.X = g.rnd(bsze.X-4) + 4
+		rp.Max.Y = g.rnd(bsze.Y-4) + 4
+		rp.Pos.X = top.X + g.rnd(bsze.X-rp.Max.X)
+
+		rp.Pos.Y = top.Y + g.rnd(bsze.Y-rp.Max.Y)
+		if rp.Pos.Y != 0 {
+			return
 		}
 	}
 }
 
+// roomGold maybe puts a gold pile in the room (rooms.c do_rooms).
+func (g *RogueGame) roomGold(rp *Room) {
+	if g.rnd(2) != 0 || (g.HasAmulet && g.Depth < g.MaxDepth) {
+		return
+	}
+
+	gold := newObject()
+	rp.GoldVal = g.goldCalc()
+	gold.GoldValue = rp.GoldVal
+	rp.Gold, _ = g.findFloorIn(rp, 0, false)
+	gold.Pos = rp.Gold
+	g.Level.SetChar(rp.Gold.Y, rp.Gold.X, Gold)
+
+	gold.Flags = Stackable
+	gold.Group = goldGrp
+	gold.Kind = KindGold
+	g.Level.AddObject(gold)
+}
+
+// roomMonster maybe puts a monster in the room; gold attracts them
+// (rooms.c do_rooms).
+func (g *RogueGame) roomMonster(rp *Room) {
+	prob := 25
+	if rp.GoldVal > 0 {
+		prob = 80
+	}
+
+	if g.rnd(100) < prob {
+		tp := &Monster{}
+		mp, _ := g.findFloorIn(rp, 0, true)
+		g.newMonster(tp, g.randMonster(false), mp)
+		g.givePack(tp)
+	}
+}
+
 // drawRoom draws a box around a room and lays down the floor for normal
 // rooms; for maze rooms, draws the maze (rooms.c draw_room).
 func (g *RogueGame) drawRoom(rp *Room) {
-	if rp.Flags.Has(IsMaze) {
-		g.doMaze(rp)
+	if rp.Flags.Has(Maze) {
+		g.digMaze(rp)
+
 		return
 	}
+
 	g.vert(rp, rp.Pos.X)             // Draw left side
 	g.vert(rp, rp.Pos.X+rp.Max.X-1)  // Draw right side
 	g.horiz(rp, rp.Pos.Y)            // Draw top
@@ -145,8 +190,8 @@ func (g *RogueGame) horiz(rp *Room, starty int) {
 	}
 }
 
-// doMaze digs a maze (rooms.c do_maze).
-func (g *RogueGame) doMaze(rp *Room) {
+// digMaze digs a maze (rooms.c do_maze).
+func (g *RogueGame) digMaze(rp *Room) {
 	m := &g.maze
 	for y := range m.maze {
 		for x := range m.maze[y] {
@@ -162,65 +207,84 @@ func (g *RogueGame) doMaze(rp *Room) {
 	starty := (g.rnd(rp.Max.Y) / 2) * 2
 	startx := (g.rnd(rp.Max.X) / 2) * 2
 	pos := Coord{Y: starty + m.starty, X: startx + m.startx}
-	g.putpass(pos)
+	g.putPassage(pos)
 	g.dig(starty, startx)
 }
 
 // dig digs out from around where we are now, if possible (rooms.c dig).
 func (g *RogueGame) dig(y, x int) {
 	m := &g.maze
-	del := [4]Coord{{X: 2, Y: 0}, {X: -2, Y: 0}, {X: 0, Y: 2}, {X: 0, Y: -2}}
 
 	for {
-		cnt := 0
-		var nexty, nextx int
-		for _, cp := range del {
-			newy := y + cp.Y
-			newx := x + cp.X
-			if newy < 0 || newy > m.maxy || newx < 0 || newx > m.maxx {
-				continue
-			}
-			if g.Level.FlagsAt(newy+m.starty, newx+m.startx).Has(FPass) {
-				continue
-			}
-			if cnt++; g.rnd(cnt) == 0 {
-				nexty = newy
-				nextx = newx
-			}
-		}
-		if cnt == 0 {
+		nexty, nextx, ok := g.digPick(y, x)
+		if !ok {
 			return
 		}
-		g.accntMaze(y, x, nexty, nextx)
-		g.accntMaze(nexty, nextx, y, x)
-		var pos Coord
-		if nexty == y {
-			pos.Y = y + m.starty
-			if nextx-x < 0 {
-				pos.X = nextx + m.startx + 1
-			} else {
-				pos.X = nextx + m.startx - 1
-			}
-		} else {
-			pos.X = x + m.startx
-			if nexty-y < 0 {
-				pos.Y = nexty + m.starty + 1
-			} else {
-				pos.Y = nexty + m.starty - 1
-			}
-		}
-		g.putpass(pos)
-		pos.Y = nexty + m.starty
-		pos.X = nextx + m.startx
-		g.putpass(pos)
+
+		g.accountMaze(y, x, nexty, nextx)
+		g.accountMaze(nexty, nextx, y, x)
+
+		g.putPassage(digWallGap(m, y, x, nexty, nextx))
+		g.putPassage(Coord{Y: nexty + m.starty, X: nextx + m.startx})
 		g.dig(nexty, nextx)
 	}
 }
 
-// accntMaze accounts for maze exits (rooms.c accnt_maze).
-func (g *RogueGame) accntMaze(y, x, ny, nx int) {
+// digPick reservoir-picks the next unvisited maze cell; ok is false
+// when the digger is boxed in (the candidate scan of rooms.c dig).
+func (g *RogueGame) digPick(y, x int) (int, int, bool) {
+	m := &g.maze
+	del := [4]Coord{{X: 2, Y: 0}, {X: -2, Y: 0}, {X: 0, Y: 2}, {X: 0, Y: -2}}
+
+	cnt := 0
+
+	var nexty, nextx int
+
+	for _, cp := range del {
+		newy := y + cp.Y
+
+		newx := x + cp.X
+		if newy < 0 || newy > m.maxy || newx < 0 || newx > m.maxx {
+			continue
+		}
+
+		if g.Level.FlagsAt(newy+m.starty, newx+m.startx).Has(FPassage) {
+			continue
+		}
+
+		if cnt++; g.rnd(cnt) == 0 {
+			nexty = newy
+			nextx = newx
+		}
+	}
+
+	return nexty, nextx, cnt != 0
+}
+
+// digWallGap picks the wall square to knock out between two maze cells
+// (rooms.c dig).
+func digWallGap(m *mazeState, y, x, nexty, nextx int) Coord {
+	if nexty == y {
+		pos := Coord{Y: y + m.starty, X: nextx + m.startx - 1}
+		if nextx-x < 0 {
+			pos.X = nextx + m.startx + 1
+		}
+
+		return pos
+	}
+
+	pos := Coord{X: x + m.startx, Y: nexty + m.starty - 1}
+	if nexty-y < 0 {
+		pos.Y = nexty + m.starty + 1
+	}
+
+	return pos
+}
+
+// accountMaze accounts for maze exits (rooms.c accnt_maze).
+func (g *RogueGame) accountMaze(y, x, ny, nx int) {
 	sp := &g.maze.maze[y][x]
-	for i := 0; i < sp.nexits; i++ {
+	for i := range sp.nexits {
 		if sp.exits[i].Y == ny && sp.exits[i].X == nx {
 			return
 		}
@@ -233,18 +297,21 @@ func (g *RogueGame) accntMaze(y, x, ny, nx int) {
 	}
 }
 
-// rndPos picks a random spot in a room (rooms.c rnd_pos).
-func (g *RogueGame) rndPos(rp *Room) Coord {
+// randomPos picks a random spot in a room (rooms.c rnd_pos).
+func (g *RogueGame) randomPos(rp *Room) Coord {
 	var cp Coord
+
 	cp.X = rp.Pos.X + g.rnd(rp.Max.X-2) + 1
 	cp.Y = rp.Pos.Y + g.rnd(rp.Max.Y-2) + 1
+
 	return cp
 }
 
 // findFloor finds a valid floor spot, picking a new random room each time
-// around the loop (rooms.c find_floor with rp == NULL).
-func (g *RogueGame) findFloor(rp *Room, limit int, monst bool) (Coord, bool) {
-	return g.findFloorImpl(rp, limit, monst, rp == nil)
+// around the loop; it retries forever (rooms.c find_floor with rp == NULL
+// — every such C call site passed FALSE for the limit).
+func (g *RogueGame) findFloor(monst bool) (Coord, bool) {
+	return g.findFloorImpl(nil, 0, monst, true)
 }
 
 // findFloorIn finds a valid floor spot in this room (rooms.c find_floor
@@ -253,14 +320,22 @@ func (g *RogueGame) findFloorIn(rp *Room, limit int, monst bool) (Coord, bool) {
 	return g.findFloorImpl(rp, limit, monst, false)
 }
 
+// floorChar is what an empty spot looks like in a room: passage in a
+// maze, floor otherwise (rooms.c find_floor).
+func floorChar(rp *Room) byte {
+	if rp.Flags.Has(Maze) {
+		return Passage
+	}
+
+	return Floor
+}
+
 func (g *RogueGame) findFloorImpl(rp *Room, limit int, monst, pickroom bool) (Coord, bool) {
 	var compchar byte
 	if !pickroom {
-		compchar = Floor
-		if rp.Flags.Has(IsMaze) {
-			compchar = Passage
-		}
+		compchar = floorChar(rp)
 	}
+
 	cnt := limit
 	for {
 		if limit != 0 {
@@ -268,14 +343,14 @@ func (g *RogueGame) findFloorImpl(rp *Room, limit int, monst, pickroom bool) (Co
 				return Coord{}, false
 			}
 		}
+
 		if pickroom {
-			rp = &g.Level.Rooms[g.rndRoom()]
-			compchar = Floor
-			if rp.Flags.Has(IsMaze) {
-				compchar = Passage
-			}
+			rp = &g.Level.Rooms[g.randomRoom()]
+			compchar = floorChar(rp)
 		}
-		cp := g.rndPos(rp)
+
+		cp := g.randomPos(rp)
+
 		pp := g.Level.At(cp.Y, cp.X)
 		if monst {
 			if pp.Monst == nil && stepOk(pp.Ch) {
@@ -291,87 +366,113 @@ func (g *RogueGame) findFloorImpl(rp *Room, limit int, monst, pickroom bool) (Co
 // enter_room).
 func (g *RogueGame) enterRoom(cp Coord) {
 	p := &g.Player
-	rp := g.roomin(cp)
+	rp := g.roomIn(cp)
 	p.Room = rp
 	g.doorOpen(rp)
-	if !rp.Flags.Has(IsDark) && !p.On(IsBlind) {
+
+	if !rp.Flags.Has(Dark) && !p.On(Blind) {
 		for y := rp.Pos.Y; y < rp.Max.Y+rp.Pos.Y; y++ {
 			g.move(y, rp.Pos.X)
+
 			for x := rp.Pos.X; x < rp.Max.X+rp.Pos.X; x++ {
-				tp := g.Level.MonsterAt(y, x)
-				ch := g.Level.Char(y, x)
-				if tp == nil {
-					if g.inch() != ch {
-						g.addch(ch)
-					} else {
-						g.move(y, x+1)
-					}
-				} else {
-					tp.OldCh = ch
-					if !g.seeMonst(tp) {
-						if p.On(SeeMonst) {
-							g.standout()
-							g.addch(tp.Disguise)
-							g.standend()
-						} else {
-							g.addch(ch)
-						}
-					} else {
-						g.addch(tp.Disguise)
-					}
-				}
+				g.enterRoomCell(y, x)
 			}
 		}
 	}
 }
 
+// enterRoomCell draws one square of a room being lit on entry (the loop
+// body of rooms.c enter_room).
+func (g *RogueGame) enterRoomCell(y, x int) {
+	tp := g.Level.MonsterAt(y, x)
+
+	ch := g.Level.Char(y, x)
+	if tp == nil {
+		if g.inch() != ch {
+			g.addch(ch)
+		} else {
+			g.move(y, x+1)
+		}
+
+		return
+	}
+
+	tp.OldCh = ch
+	if g.seeMonst(tp) {
+		g.addch(tp.Disguise)
+
+		return
+	}
+
+	if g.Player.On(SenseMonsters) {
+		g.standout()
+		g.addch(tp.Disguise)
+		g.standend()
+	} else {
+		g.addch(ch)
+	}
+}
+
 // leaveRoom is the code for when we exit a room (rooms.c leave_room).
 func (g *RogueGame) leaveRoom(cp Coord) {
 	p := &g.Player
 	rp := p.Room
 
-	if rp.Flags.Has(IsMaze) {
+	if rp.Flags.Has(Maze) {
 		return
 	}
 
 	var floor byte
+
 	switch {
-	case rp.Flags.Has(IsGone):
+	case rp.Flags.Has(Gone):
 		floor = Passage
-	case !rp.Flags.Has(IsDark) || p.On(IsBlind):
+	case !rp.Flags.Has(Dark) || p.On(Blind):
 		floor = Floor
 	default:
 		floor = ' '
 	}
 
-	p.Room = &g.Level.Passages[*g.Level.FlagsAt(cp.Y, cp.X)&FPNum]
+	p.Room = &g.Level.Passages[*g.Level.FlagsAt(cp.Y, cp.X)&FPassNum]
 	for y := rp.Pos.Y; y < rp.Max.Y+rp.Pos.Y; y++ {
 		for x := rp.Pos.X; x < rp.Max.X+rp.Pos.X; x++ {
-			g.move(y, x)
-			switch ch := g.inch(); ch {
-			case Floor:
-				if floor == ' ' {
-					g.addch(' ')
-				}
-			default:
-				// to check for monster, we have to strip out the standout
-				// bit (our Window returns the bare character already)
-				if isUpper(ch) {
-					if p.On(SeeMonst) {
-						g.standout()
-						g.addch(ch)
-						g.standend()
-						break
-					}
-					pp := g.Level.At(y, x)
-					if pp.Ch == Door {
-						g.addch(Door)
-					} else {
-						g.addch(floor)
-					}
-				}
-			}
+			g.leaveRoomCell(floor, y, x)
 		}
 	}
+
 	g.doorOpen(rp)
 }
+
+// leaveRoomCell hides one square of a room being left (the loop body of
+// rooms.c leave_room).
+func (g *RogueGame) leaveRoomCell(floor byte, y, x int) {
+	g.move(y, x)
+
+	switch ch := g.inch(); ch {
+	case Floor:
+		if floor == ' ' {
+			g.addch(' ')
+		}
+	default:
+		// to check for monster, we have to strip out the standout
+		// bit (our Window returns the bare character already)
+		if !isUpper(ch) {
+			return
+		}
+
+		if g.Player.On(SenseMonsters) {
+			g.standout()
+			g.addch(ch)
+			g.standend()
+
+			return
+		}
+
+		pp := g.Level.At(y, x)
+		if pp.Ch == Door {
+			g.addch(Door)
+		} else {
+			g.addch(floor)
+		}
+	}
+}

game/run_test.go

@@ -1,104 +1,204 @@
 package game
 
 import (
+	"path/filepath"
 	"strings"
 	"testing"
 )
 
-// TestRunScriptedSession drives a complete game through Run(): a few
-// moves, a rest, an inventory, then Q-quit answered yes.
-func TestRunScriptedSession(t *testing.T) {
-	tt := &testTerm{input: []byte("hjkl.i Qy")}
-	g := NewGame(Config{Seed: 99, Term: tt})
-	if err := g.Run(); err != nil {
-		t.Fatalf("Run: %v", err)
-	}
-	if g.Playing {
-		t.Error("still playing after quit")
-	}
-	// After quitting, the scoreboard is the last thing shown (in C it went
-	// to stdout after endwin; here it is drawn on the screen).
-	found := false
-	for y := 0; y < NumLines; y++ {
-		if strings.Contains(g.scr.Std.Line(y), "Top Ten") {
-			found = true
-		}
-	}
-	if !found {
-		t.Error("score list not on screen after quit")
+// fortify makes the hero effectively immortal for a crash-sweep drive:
+// game-over now calls myExit and os.Exit(0) (step 8), which would kill the
+// test binary, so every death vector is neutralized. Re-applied each turn
+// because combat, digestion, freezing, and level drain chip away at these.
+func fortify(g *RogueGame) {
+	p := &g.Player
+	p.Stats.HP = 30000    // survive combat, arrow/dart traps, bolts
+	p.Stats.MaxHP = 30000 // survive vampire max-hp drain
+	p.Stats.Exp = 30000   // survive wraith level drain (death when exp hits 0)
+	p.FoodLeft = 30000    // never starve
+	g.NoCommand = 0       // never freeze to death (ice monster / sleep trap)
+	g.NoMove = 0          // never stay stuck in a bear trap
+}
+
+// driveTurns runs the game's per-turn loop up to n times, doing the same
+// first-level and pre-play setup Run() does. Run() itself no longer
+// returns — game-over exits the process — so tests drive command()
+// directly, with short scripts that avoid quitting, saving, or playing
+// long enough to starve, any of which would exit the test binary.
+func driveTurns(t *testing.T, g *RogueGame, n int) {
+	t.Helper()
+
+	g.startLevel()
+	g.prePlay()
+
+	for range n {
+		g.command()
 	}
 }
 
-// TestRunManyTurns mashes movement keys for a while as a crash sweep of
-// the whole turn loop (daemons, hunger, monsters, combat), ending with a
-// quit. The input alternates directions so the hero bumps around rooms.
-func TestRunManyTurns(t *testing.T) {
-	// Spaces between commands double as answers to any --More-- prompts;
-	// without them a single prompt would swallow the rest of the script
-	// (wait_for eats everything that isn't a space).
-	var script []byte
-	moves := []byte("h h j j k k l l y u b n s s . . ")
-	for range 200 {
-		script = append(script, moves...)
-	}
-	script = append(script, " Q y Qy"...)
-	tt := &testTerm{input: script}
-	g := NewGame(Config{Seed: 31337, Term: tt})
-	if err := g.Run(); err != nil {
-		t.Fatalf("Run: %v", err)
-	}
-	if g.Playing {
-		t.Error("session did not end")
-	}
-}
-
-// TestRunDownStairs walks the hero onto the stairs by teleporting there in
-// wizard style, then descends and keeps playing.
+// TestRunDownStairs stands the hero on the staircase and descends via the
+// '>' command through the real turn loop, then checks the level changed.
 func TestRunDownStairs(t *testing.T) {
-	tt := &testTerm{input: []byte(">..Qy")}
-	g := NewGame(Config{Seed: 7, Term: tt})
+	// '>' is a free action (After=false), so it is followed by a paying
+	// rest ('.') to end the command() call; without a paying action the
+	// turn loop would spin forever on the auto-fed prompt input.
+	tt := &testTerm{input: []byte(">.")}
+	g := New(Params{Seed: 7, Term: tt})
 	g.NewLevel()
 	g.Player.Pos = g.Level.Stairs // stand on the stairs
-	g.restored = true             // keep Run from regenerating the level
+	g.restored = true             // keep startLevel from regenerating
 	g.Daemons = DaemonList{}      // and give it a fresh daemon table
 	g.StartDaemon(DRunners, 0, After)
 	g.StartDaemon(DDoctor, 0, After)
 	g.Fuse(DSwander, 0, wanderTime(g), After)
 	g.StartDaemon(DStomach, 0, After)
-	if err := g.Run(); err != nil {
-		t.Fatalf("Run: %v", err)
-	}
+
+	driveTurns(t, g, 1)
+
 	if g.Depth != 2 {
 		t.Errorf("depth = %d after descending, want 2", g.Depth)
 	}
 }
 
-// TestSaveCommandRoundTrip saves via the 'S' command (as a player would)
-// and restores the game.
-func TestSaveCommandRoundTrip(t *testing.T) {
-	// The C get_str caps input at MAXINP=50 characters, so the save path
-	// must be short: work from the temp directory.
-	t.Chdir(t.TempDir())
-	path := "cmd.save"
-	// 'S' with no default file name goes straight to the name prompt.
-	script := "S" + path + "\n"
-	tt := &testTerm{input: []byte(script)}
-	g := NewGame(Config{Seed: 55, Term: tt})
-	g.FileName = "" // force the name prompt
-	if err := g.Run(); err != nil {
-		t.Fatalf("Run: %v", err)
+// TestScoreRendersList checks that the scoreboard is drawn on the screen
+// (in C it went to stdout after endwin; here it stays on the screen). The
+// quit and death paths that normally show it now exit the process, so the
+// display is exercised through score() directly.
+func TestScoreRendersList(t *testing.T) {
+	g := New(Params{Seed: 1, Term: &testTerm{}})
+	g.Player.Purse = 100
+
+	g.score(g.Player.Purse, 1, 0) // flags 1 = quit; posts the top-ten list
+
+	found := false
+
+	for y := range NumLines {
+		if strings.Contains(g.scr.Std.Line(y), "Top Ten") {
+			found = true
+		}
 	}
 
-	h, err := Restore(path, Config{Term: &testTerm{}})
+	if !found {
+		t.Error("score list not on screen")
+	}
+}
+
+// TestDeepPlaythrough drives a fortified hero through the real command loop:
+// quaff/read/zap on the first level, then descend through the staircase to
+// depth 8, saving and restoring mid-way. It is a crash sweep of the turn
+// engine, deep level generation, item effects, and mid-game save/restore.
+// The hero is fortified so no death exits the process (step 8), and the fixed
+// seed keeps it deterministic.
+func TestDeepPlaythrough(t *testing.T) {
+	g := New(Params{Seed: 4242, Wizard: true, Term: &testTerm{}})
+	g.startLevel()
+	g.prePlay()
+	fortify(g)
+
+	// Stock and use one of each consumable through the command dispatch.
+	pot := give(g, &Object{Kind: KindPotion, Which: int(PotionHealing)})
+	scr := give(g, &Object{Kind: KindScroll, Which: int(ScrollMagicMapping)})
+
+	wand := newObject()
+	wand.Kind = KindWand
+	wand.Which = int(WandLight)
+	wand.Charges = 5
+	zap := give(g, wand)
+
+	setInput(t, g, 'q', pot) // quaff healing
+	g.command()
+	setInput(t, g, 'r', scr) // read magic mapping
+	g.command()
+	setInput(t, g, 'z', 'h', zap) // zap the light wand west
+	g.command()
+	fortify(g)
+
+	// Each consumable identifies itself on use, confirming the q/r/z
+	// commands actually ran through dispatch (not aborted on a bad prompt).
+	if !g.Items.Potions[PotionHealing].Know {
+		t.Error("quaff command did not identify the healing potion")
+	}
+
+	if !g.Items.Scrolls[ScrollMagicMapping].Know {
+		t.Error("read command did not identify the magic-mapping scroll")
+	}
+
+	if !g.Items.Sticks[WandLight].Know {
+		t.Error("zap command did not identify the light wand")
+	}
+
+	const wantDepth = 8
+
+	for g.Depth < wantDepth {
+		g.Player.Pos = g.Level.Stairs // stand on the stairs
+		setInput(t, g, '>', '.')      // '>' descends (free), '.' pays the turn
+		g.command()
+		fortify(g)
+
+		if g.Depth == 4 {
+			g = saveAndRestore(t, g)
+			fortify(g)
+		}
+	}
+
+	if g.Depth != wantDepth {
+		t.Errorf("depth = %d after descending, want %d", g.Depth, wantDepth)
+	}
+
+	if g.Player.Stats.HP <= 0 {
+		t.Error("hero died during the playthrough")
+	}
+}
+
+// TestTurnLoopCrashSweep mashes movement, search, and rest through the real
+// turn loop for many turns on several seeds, exercising combat, monster AI,
+// and traps. The hero is fortified each turn so nothing exits the process,
+// and the fixed seeds keep it deterministic; the point is to surface panics.
+func TestTurnLoopCrashSweep(t *testing.T) {
+	// A generous mix of movement, search, and rest. The spaces between
+	// commands double as answers to any --More-- prompt (wait_for eats
+	// everything up to a space); without them one prompt would swallow the
+	// rest of the script. The script is long enough that the bounded drive
+	// never exhausts it (which would spin on the auto-fed prompt input).
+	script := []byte(strings.Repeat("h j k l y u b n s . ", 400))
+
+	for _, seed := range []int32{1, 99, 2026, 31337} {
+		g := New(Params{Seed: seed, Term: &testTerm{input: script}})
+		g.startLevel()
+		g.prePlay()
+
+		for range 200 {
+			fortify(g)
+			g.command()
+		}
+
+		if g.Player.Stats.HP <= 0 {
+			t.Errorf("seed %d: hero died despite fortify", seed)
+		}
+	}
+}
+
+// saveAndRestore snapshots the game to a file, restores it, checks the key
+// state survived, and returns the restored game ready to keep playing.
+func saveAndRestore(t *testing.T, g *RogueGame) *RogueGame {
+	t.Helper()
+
+	path := filepath.Join(t.TempDir(), "deep.save")
+
+	saveErr := g.saveFile(path)
+	if saveErr != nil {
+		t.Fatalf("saveFile: %v", saveErr)
+	}
+
+	h, err := Restore(path, Params{Wizard: true, Term: &testTerm{}})
 	if err != nil {
 		t.Fatalf("Restore: %v", err)
 	}
+
 	if h.Depth != g.Depth || h.Player.Purse != g.Player.Purse {
-		t.Error("restored game does not match saved game")
-	}
-	// The restored game must be playable.
-	h.scr.term.(*testTerm).input = []byte("..Qy")
-	if err := h.Run(); err != nil {
-		t.Fatalf("restored Run: %v", err)
+		t.Errorf("restored game diverged: depth %d/%d purse %d/%d",
+			h.Depth, g.Depth, h.Player.Purse, g.Player.Purse)
 	}
+
+	return h
 }

game/save.go

@@ -2,6 +2,7 @@ package game
 
 import (
 	"encoding/gob"
+	"errors"
 	"fmt"
 	"os"
 )
@@ -11,6 +12,13 @@ import (
 // what state.c's rs_fix_thing did: pointers that alias other structures
 // (equipment, chase targets, room membership) are encoded as indices.
 
+// saveFormatVersion identifies the snapshot layout; it changes whenever a
+// field rename or retype would make gob silently mis-decode an older
+// save ("go2": Object.Type became Kind ObjectKind; "go3": Object.Arm split
+// into ArmorClass/Charges/GoldValue/Bonus, damage strings became
+// DiceSpec).
+const saveFormatVersion = Release + "-go3"
+
 // destRef encodes a monster's chase target (state.c rs_write_thing's
 // (kind, index) pairs).
 type destRef struct {
@@ -74,14 +82,14 @@ type SaveState struct {
 	HasAmulet  bool
 	SeenStairs bool
 
-	Places   []savedPlace
-	Rooms    [MaxRooms]Room
-	Passages [MaxPass]Room
-	Objects  []Object
-	Monsters []savedCreature
-	Dests    []destRef // parallel to Monsters
-	Stairs   Coord
-	NTraps   int
+	Places    []savedPlace
+	Rooms     [MaxRooms]Room
+	Passages  [MaxPass]Room
+	Objects   []Object
+	Monsters  []savedCreature
+	Dests     []destRef // parallel to Monsters
+	Stairs    Coord
+	TrapCount int
 
 	After     bool
 	Again     bool
@@ -124,16 +132,19 @@ func (g *RogueGame) roomIdx(rp *Room) int {
 	if rp == nil {
 		return -1
 	}
+
 	for i := range g.Level.Rooms {
 		if rp == &g.Level.Rooms[i] {
 			return i
 		}
 	}
+
 	for i := range g.Level.Passages {
 		if rp == &g.Level.Passages[i] {
 			return 100 + i
 		}
 	}
+
 	return -1
 }
 
@@ -145,6 +156,7 @@ func (g *RogueGame) roomAt(i int) *Room {
 	case i >= 0:
 		return &g.Level.Rooms[i]
 	}
+
 	return nil
 }
 
@@ -153,19 +165,61 @@ func (g *RogueGame) packIdx(obj *Object) int {
 	if obj == nil {
 		return -1
 	}
+
 	for i, o := range g.Player.Pack {
 		if o == obj {
 			return i
 		}
 	}
+
 	return -1
 }
 
 // snapshot captures the complete game state.
 func (g *RogueGame) snapshot() *SaveState {
-	p := &g.Player
-	st := &SaveState{
-		Version:    Release,
+	st := g.snapshotHeader()
+
+	// the map, sans monster pointers (rebuilt on load)
+	st.Places = make([]savedPlace, len(g.Level.Places))
+	for i := range g.Level.Places {
+		st.Places[i] = savedPlace{
+			Ch:    g.Level.Places[i].Ch,
+			Flags: g.Level.Places[i].Flags,
+		}
+	}
+
+	// level objects by value; remember their pointers for dest encoding
+	objAt := make(map[*Object]int, len(g.Level.Objects))
+	for i, o := range g.Level.Objects {
+		st.Objects = append(st.Objects, *o)
+		objAt[o] = i
+	}
+
+	st.Player = g.snapshotPlayer()
+
+	// monsters, with chase targets as (kind, index) references
+	for _, m := range g.Level.Monsters {
+		sc := savedCreature{
+			Pos: m.Pos, Turn: m.Turn, Type: m.Type, Disguise: m.Disguise,
+			OldCh: m.OldCh, Flags: m.Flags, Stats: m.Stats,
+			RoomIdx: g.roomIdx(m.Room),
+		}
+		for _, o := range m.Pack {
+			sc.Pack = append(sc.Pack, *o)
+		}
+
+		st.Monsters = append(st.Monsters, sc)
+		st.Dests = append(st.Dests, g.destRefFor(m, objAt))
+	}
+
+	return st
+}
+
+// snapshotHeader captures the scalar game state (the field list of
+// state.c rs_save_file).
+func (g *RogueGame) snapshotHeader() *SaveState {
+	return &SaveState{
+		Version:    saveFormatVersion,
 		Seed:       g.Rng.Seed,
 		Dnum:       g.Dnum,
 		Whoami:     g.Whoami,
@@ -179,7 +233,7 @@ func (g *RogueGame) snapshot() *SaveState {
 		Rooms:      g.Level.Rooms,
 		Passages:   g.Level.Passages,
 		Stairs:     g.Level.Stairs,
-		NTraps:     g.Level.NTraps,
+		TrapCount:  g.Level.TrapCount,
 		After:      g.After,
 		Again:      g.Again,
 		NoScoreF:   g.NoScore,
@@ -212,25 +266,14 @@ func (g *RogueGame) snapshot() *SaveState {
 		AllScore:   g.AllScore,
 		Screen:     g.scr.Std.Contents(),
 	}
+}
 
-	// the map, sans monster pointers (rebuilt on load)
-	st.Places = make([]savedPlace, len(g.Level.Places))
-	for i := range g.Level.Places {
-		st.Places[i] = savedPlace{
-			Ch:    g.Level.Places[i].Ch,
-			Flags: g.Level.Places[i].Flags,
-		}
-	}
+// snapshotPlayer captures the player, equipment as pack indices (the
+// player half of snapshot).
+func (g *RogueGame) snapshotPlayer() savedPlayer {
+	p := &g.Player
 
-	// level objects by value; remember their pointers for dest encoding
-	objAt := make(map[*Object]int, len(g.Level.Objects))
-	for i, o := range g.Level.Objects {
-		st.Objects = append(st.Objects, *o)
-		objAt[o] = i
-	}
-
-	// the player
-	st.Player = savedPlayer{
+	sp := savedPlayer{
 		Body: savedCreature{
 			Pos: p.Pos, Turn: p.Turn, Type: p.Type, Disguise: p.Disguise,
 			OldCh: p.OldCh, Flags: p.Flags, Stats: p.Stats,
@@ -246,55 +289,72 @@ func (g *RogueGame) snapshot() *SaveState {
 		MaxStats: p.MaxStats, VfHit: p.VfHit,
 	}
 	for _, o := range p.Pack {
-		st.Player.Body.Pack = append(st.Player.Body.Pack, *o)
+		sp.Body.Pack = append(sp.Body.Pack, *o)
 	}
 
-	// monsters, with chase targets as (kind, index) references
-	for _, m := range g.Level.Monsters {
-		sc := savedCreature{
-			Pos: m.Pos, Turn: m.Turn, Type: m.Type, Disguise: m.Disguise,
-			OldCh: m.OldCh, Flags: m.Flags, Stats: m.Stats,
-			RoomIdx: g.roomIdx(m.Room),
-		}
-		for _, o := range m.Pack {
-			sc.Pack = append(sc.Pack, *o)
-		}
-		st.Monsters = append(st.Monsters, sc)
+	return sp
+}
 
-		ref := destRef{}
-		switch {
-		case m.Dest == nil:
-		case m.Dest == &p.Pos:
-			ref = destRef{Kind: 1}
-		default:
-			for mi, om := range g.Level.Monsters {
-				if m.Dest == &om.Pos {
-					ref = destRef{Kind: 2, Idx: mi}
-				}
-			}
-			if ref.Kind == 0 {
-				for _, oo := range g.Level.Objects {
-					if m.Dest == &oo.Pos {
-						ref = destRef{Kind: 3, Idx: objAt[oo]}
-					}
-				}
-			}
-			if ref.Kind == 0 {
-				for ri := range g.Level.Rooms {
-					if m.Dest == &g.Level.Rooms[ri].Gold {
-						ref = destRef{Kind: 4, Idx: ri}
-					}
-				}
-			}
-		}
-		st.Dests = append(st.Dests, ref)
+// destRefFor encodes a monster's chase target as a (kind, index)
+// reference: the hero, another monster, a level object, or room gold
+// (state.c rs_write_thing).
+func (g *RogueGame) destRefFor(m *Monster, objAt map[*Object]int) destRef {
+	switch {
+	case m.Dest == nil:
+		return destRef{}
+	case m.Dest == &g.Player.Pos:
+		return destRef{Kind: 1}
 	}
-	return st
+
+	for mi, om := range g.Level.Monsters {
+		if m.Dest == &om.Pos {
+			return destRef{Kind: 2, Idx: mi}
+		}
+	}
+
+	for _, oo := range g.Level.Objects {
+		if m.Dest == &oo.Pos {
+			return destRef{Kind: 3, Idx: objAt[oo]}
+		}
+	}
+
+	for ri := range g.Level.Rooms {
+		if m.Dest == &g.Level.Rooms[ri].Gold {
+			return destRef{Kind: 4, Idx: ri}
+		}
+	}
+
+	return destRef{}
 }
 
 // applySnapshot rebuilds live game state from a snapshot.
 func (g *RogueGame) applySnapshot(st *SaveState) {
-	p := &g.Player
+	g.applyHeader(st)
+
+	for i := range g.Level.Places {
+		g.Level.Places[i] = Place{
+			Ch:    st.Places[i].Ch,
+			Flags: st.Places[i].Flags,
+		}
+	}
+
+	// level objects
+	g.Level.Objects = nil
+	for i := range st.Objects {
+		o := st.Objects[i]
+		g.Level.Objects = append(g.Level.Objects, &o)
+	}
+
+	g.applyPlayer(st)
+	g.applyMonsters(st)
+	g.applyDests(st)
+
+	g.scr.Std.SetContents(st.Screen)
+}
+
+// applyHeader restores the scalar game state (the field list of
+// applySnapshot).
+func (g *RogueGame) applyHeader(st *SaveState) {
 	g.Rng.Seed = st.Seed
 	g.Dnum = st.Dnum
 	g.Whoami = st.Whoami
@@ -308,7 +368,13 @@ func (g *RogueGame) applySnapshot(st *SaveState) {
 	g.Level.Rooms = st.Rooms
 	g.Level.Passages = st.Passages
 	g.Level.Stairs = st.Stairs
-	g.Level.NTraps = st.NTraps
+	g.Level.TrapCount = st.TrapCount
+	g.applyTurnState(st)
+}
+
+// applyTurnState restores the in-turn command state (the second half of
+// applyHeader).
+func (g *RogueGame) applyTurnState(st *SaveState) {
 	g.After = st.After
 	g.Again = st.Again
 	g.NoScore = st.NoScoreF
@@ -339,22 +405,12 @@ func (g *RogueGame) applySnapshot(st *SaveState) {
 	g.LastScore = st.LastScore
 	g.AllScore = st.AllScore
 	g.Playing = true
+}
 
-	for i := range g.Level.Places {
-		g.Level.Places[i] = Place{
-			Ch:    st.Places[i].Ch,
-			Flags: st.Places[i].Flags,
-		}
-	}
-
-	// level objects
-	g.Level.Objects = nil
-	for i := range st.Objects {
-		o := st.Objects[i]
-		g.Level.Objects = append(g.Level.Objects, &o)
-	}
-
-	// the player
+// applyPlayer restores the player, resolving equipment pack indices
+// (the player half of applySnapshot).
+func (g *RogueGame) applyPlayer(st *SaveState) {
+	p := &g.Player
 	sp := &st.Player
 	p.Pos = sp.Body.Pos
 	p.Turn = sp.Body.Turn
@@ -364,15 +420,18 @@ func (g *RogueGame) applySnapshot(st *SaveState) {
 	p.Flags = sp.Body.Flags
 	p.Stats = sp.Body.Stats
 	p.Room = g.roomAt(sp.Body.RoomIdx)
+
 	p.Pack = nil
 	for i := range sp.Body.Pack {
 		o := sp.Body.Pack[i]
 		p.Pack = append(p.Pack, &o)
 	}
+
 	pick := func(i int) *Object {
 		if i < 0 || i >= len(p.Pack) {
 			return nil
 		}
+
 		return p.Pack[i]
 	}
 	p.CurArmor = pick(sp.CurArmor)
@@ -388,11 +447,15 @@ func (g *RogueGame) applySnapshot(st *SaveState) {
 	p.NoFood = sp.NoFood
 	p.MaxStats = sp.MaxStats
 	p.VfHit = sp.VfHit
+}
 
-	// monsters, their map index, and their chase targets
+// applyMonsters rebuilds the monster list and its map index from a
+// snapshot (the monster half of applySnapshot).
+func (g *RogueGame) applyMonsters(st *SaveState) {
 	g.Level.Monsters = nil
 	for i := range st.Monsters {
 		sc := &st.Monsters[i]
+
 		m := &Monster{Creature: Creature{
 			Pos: sc.Pos, Turn: sc.Turn, Type: sc.Type, Disguise: sc.Disguise,
 			OldCh: sc.OldCh, Flags: sc.Flags, Stats: sc.Stats,
@@ -402,14 +465,21 @@ func (g *RogueGame) applySnapshot(st *SaveState) {
 			o := sc.Pack[j]
 			m.Pack = append(m.Pack, &o)
 		}
+
 		g.Level.Monsters = append(g.Level.Monsters, m)
 		g.Level.SetMonsterAt(m.Pos.Y, m.Pos.X, m)
 	}
+}
+
+// applyDests re-aims the monsters' chase targets from their (kind,
+// index) references (the fixup half of applySnapshot).
+func (g *RogueGame) applyDests(st *SaveState) {
 	for i, ref := range st.Dests {
 		m := g.Level.Monsters[i]
+
 		switch ref.Kind {
 		case 1:
-			m.Dest = &p.Pos
+			m.Dest = &g.Player.Pos
 		case 2:
 			m.Dest = &g.Level.Monsters[ref.Idx].Pos
 		case 3:
@@ -418,136 +488,236 @@ func (g *RogueGame) applySnapshot(st *SaveState) {
 			m.Dest = &g.Level.Rooms[ref.Idx].Gold
 		}
 	}
-
-	g.scr.Std.SetContents(st.Screen)
 }
 
-// saveGame implements the "save game" command (save.c save_game). The C
-// goto over/gotfile flow becomes the useDefault flag.
+// saveAnswer is a yes/no/escape prompt result in the save-game flow.
+type saveAnswer int
+
+// The saveGame prompt outcomes.
+const (
+	saveYes saveAnswer = iota
+	saveNo
+	saveAbort
+)
+
+// saveGame implements the "save game" command (save.c save_game). The
+// labeled prompt loop stands in for the C goto over/gotfile flow.
 func (g *RogueGame) saveGame() {
 	g.Msgs.Mpos = 0
-over:
-	useDefault := false
-	if g.FileName != "" {
-		var c byte
-		for {
-			g.msg("save file (%s)? ", g.FileName)
-			c = g.readchar()
-			g.Msgs.Mpos = 0
-			if c == Escape {
-				g.msg("")
+
+prompt:
+	for {
+		useDefault := false
+
+		if g.FileName != "" {
+			a := g.askDefaultSave()
+			if a == saveAbort {
 				return
 			}
-			if c == 'n' || c == 'N' || c == 'y' || c == 'Y' {
-				break
-			}
-			g.msg("please answer Y or N")
+
+			useDefault = a == saveYes
 		}
-		if c == 'y' || c == 'Y' {
-			g.addstr("Yes\n")
-			g.refresh()
-			useDefault = true
+
+		for {
+			buf, ok := g.saveFileName(useDefault)
+			if !ok {
+				return
+			}
+
+			useDefault = false
+
+			a := g.saveCheckOverwrite(buf)
+			if a == saveAbort {
+				return
+			}
+
+			if a == saveNo {
+				continue prompt // the C goto over: start again
+			}
+
+			g.FileName = buf
+
+			err := g.saveFile(g.FileName)
+			if err != nil {
+				g.msg("%s", err.Error())
+
+				continue
+			}
+
+			break prompt
 		}
 	}
 
-	for {
-		var buf string
-		if useDefault {
-			buf = g.FileName
-			useDefault = false
-		} else {
-			g.Msgs.Mpos = 0
-			g.msg("file name: ")
-			if g.getStr(&buf, g.scr.Std) == Quit {
-				g.msg("")
-				return
-			}
-			g.Msgs.Mpos = 0
-		}
-		// test to see if the file exists
-		if _, err := os.Stat(buf); err == nil {
-			for {
-				g.msg("File exists.  Do you wish to overwrite it?")
-				g.Msgs.Mpos = 0
-				c := g.readchar()
-				if c == Escape {
-					g.msg("")
-					return
-				}
-				if c == 'y' || c == 'Y' {
-					break
-				}
-				if c == 'n' || c == 'N' {
-					goto over
-				}
-				g.msg("Please answer Y or N")
-			}
-			g.msg("file name: %s", buf)
-			os.Remove(g.FileName)
-		}
-		g.FileName = buf
-		if err := g.saveFile(g.FileName); err != nil {
-			g.msg("%s", err.Error())
-			continue
-		}
-		break
-	}
-	g.myExit(0)
+	g.myExit()
 }
 
-// saveFile writes the saved game (save.c save_file).
+// askDefaultSave asks whether to save to the current file name (save.c
+// save_game).
+func (g *RogueGame) askDefaultSave() saveAnswer {
+	for {
+		g.msg("save file (%s)? ", g.FileName)
+		c := g.readchar()
+
+		g.Msgs.Mpos = 0
+
+		switch c {
+		case Escape:
+			g.msg("")
+
+			return saveAbort
+		case 'y', 'Y':
+			g.addstr("Yes\n")
+			g.refresh()
+
+			return saveYes
+		case 'n', 'N':
+			return saveNo
+		}
+
+		g.msg("please answer Y or N")
+	}
+}
+
+// saveFileName picks the save path: the default, or a prompted one; ok
+// is false when the player quit the prompt (save.c save_game).
+func (g *RogueGame) saveFileName(useDefault bool) (string, bool) {
+	if useDefault {
+		return g.FileName, true
+	}
+
+	g.Msgs.Mpos = 0
+	g.msg("file name: ")
+
+	buf := ""
+	if g.getStr(&buf, g.scr.Std) == Quit {
+		g.msg("")
+
+		return "", false
+	}
+
+	g.Msgs.Mpos = 0
+
+	return buf, true
+}
+
+// saveCheckOverwrite guards an existing file: saveNo restarts the whole
+// prompt, saveAbort quits (save.c save_game).
+func (g *RogueGame) saveCheckOverwrite(buf string) saveAnswer {
+	// test to see if the file exists
+	_, statErr := os.Stat(buf)
+	if statErr != nil {
+		return saveYes
+	}
+
+	answer := g.askOverwrite()
+	if answer != saveYes {
+		return answer
+	}
+
+	g.msg("file name: %s", buf)
+	_ = os.Remove(g.FileName) // best effort, as in C (md_unlink)
+
+	return saveYes
+}
+
+// askOverwrite asks whether to overwrite the existing file (save.c
+// save_game).
+func (g *RogueGame) askOverwrite() saveAnswer {
+	for {
+		g.msg("File exists.  Do you wish to overwrite it?")
+		g.Msgs.Mpos = 0
+
+		switch g.readchar() {
+		case Escape:
+			g.msg("")
+
+			return saveAbort
+		case 'y', 'Y':
+			return saveYes
+		case 'n', 'N':
+			return saveNo
+		}
+
+		g.msg("Please answer Y or N")
+	}
+}
+
+// saveFile writes the saved game (save.c save_file). A failed write means
+// a corrupt save, so the file is removed before reporting the error.
 func (g *RogueGame) saveFile(path string) error {
-	f, err := os.OpenFile(path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o400)
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o400) //nolint:gosec,lll // G304: user-chosen save path
 	if err != nil {
 		return err
 	}
-	defer f.Close()
-	if err := gob.NewEncoder(f).Encode(g.snapshot()); err != nil {
-		os.Remove(path)
-		return err
+
+	encErr := gob.NewEncoder(f).Encode(g.snapshot())
+	closeErr := f.Close()
+
+	if encErr != nil || closeErr != nil {
+		_ = os.Remove(path) // don't leave a corrupt save behind
+
+		if encErr != nil {
+			return encErr
+		}
+
+		return closeErr
 	}
+
 	return os.Chmod(path, 0o400)
 }
 
 // AutoSave silently saves to the current file name; used on SIGHUP/SIGTERM
-// (save.c auto_save).
+// (save.c auto_save). Best effort by design: it runs on the way out of a
+// dying process.
 func (g *RogueGame) AutoSave() {
 	if g.FileName != "" {
-		os.Remove(g.FileName)
-		g.saveFile(g.FileName)
+		_ = os.Remove(g.FileName)
+		_ = g.saveFile(g.FileName)
 	}
 }
 
+// ErrSaveOutOfDate reports a save file from an incompatible version.
+var ErrSaveOutOfDate = errors.New("sorry, saved game is out of date")
+
 // Restore restores a saved game from a file (save.c restore). The file is
 // deleted, as in C, to defeat restarting from the same save.
-func Restore(path string, cfg Config) (*RogueGame, error) {
-	f, err := os.Open(path)
+func Restore(path string, params Params) (*RogueGame, error) {
+	f, err := os.Open(path) //nolint:gosec // G304: the save path is user-chosen by design
 	if err != nil {
 		return nil, err
 	}
-	defer f.Close()
+	defer func() { _ = f.Close() }() // read-only handle
+
 	var st SaveState
-	if err := gob.NewDecoder(f).Decode(&st); err != nil {
-		return nil, fmt.Errorf("%s: corrupt or incompatible save file: %w", path, err)
+
+	decErr := gob.NewDecoder(f).Decode(&st)
+	if decErr != nil {
+		return nil, fmt.Errorf("%s: corrupt or incompatible save file: %w",
+			path, decErr)
 	}
-	if st.Version != Release {
-		return nil, fmt.Errorf("sorry, saved game is out of date")
+
+	if st.Version != saveFormatVersion {
+		return nil, ErrSaveOutOfDate
 	}
 
 	g := &RogueGame{
+		data:      newGameData(),
 		Rng:       &Rng{},
 		Playing:   true,
-		ScorePath: cfg.ScorePath,
+		ScorePath: params.ScorePath,
 		FileName:  path,
-		rogueOpts: cfg.RogueOpts,
+		rogueOpts: params.RogueOpts,
 		restored:  true,
 	}
-	g.scr = NewScreen(cfg.Term)
+	g.scr = NewScreen(params.Term)
+	g.Msgs.attach(g.scr, g.look, g.readchar)
 	g.applySnapshot(&st)
 
 	// defeat multiple restarting from the same place
-	if err := os.Remove(path); err != nil {
-		return nil, fmt.Errorf("cannot unlink file: %w", err)
+	rmErr := os.Remove(path)
+	if rmErr != nil {
+		return nil, fmt.Errorf("cannot unlink file: %w", rmErr)
 	}
+
 	return g, nil
 }

game/save_test.go

@@ -13,81 +13,121 @@ func TestSaveRestoreRoundTrip(t *testing.T) {
 	g.Player.Purse = 123
 	g.Player.FoodLeft = 777
 	g.HasAmulet = true
-	g.Items.Potions[PHealing].Know = true
-	g.Items.Scrolls[SMap].Guess = "map???"
-	g.Monsters['F'-'A'].Stats.Dmg = "3x1" // mutated bestiary must survive
+	g.Items.Potions[PotionHealing].Know = true
+	g.Items.Scrolls[ScrollMagicMapping].Guess = "map???"
+
+	g.Monsters['F'-'A'].Stats.Dmg = dice("3x1") // mutated bestiary must survive
 	if len(g.Level.Monsters) > 0 {
-		g.Level.Monsters[0].Flags.Set(IsRun)
+		g.Level.Monsters[0].Flags.Set(Awake)
 		g.Level.Monsters[0].Dest = &g.Player.Pos
 	}
 
 	path := filepath.Join(t.TempDir(), "rogue.save")
-	if err := g.saveFile(path); err != nil {
-		t.Fatalf("saveFile: %v", err)
+
+	saveErr := g.saveFile(path)
+	if saveErr != nil {
+		t.Fatalf("saveFile: %v", saveErr)
 	}
 
-	h, err := Restore(path, Config{Term: &testTerm{}})
+	h, err := Restore(path, Params{Term: &testTerm{}})
 	if err != nil {
 		t.Fatalf("Restore: %v", err)
 	}
 
-	if _, err := os.Stat(path); !os.IsNotExist(err) {
+	_, statErr := os.Stat(path)
+	if !os.IsNotExist(statErr) {
 		t.Error("save file not deleted on restore (C anti-restart rule)")
 	}
 
+	checkRestoredState(t, g, h)
+	checkRestoredMonsters(t, g, h)
+	checkEquipmentAliasing(t, g, h)
+}
+
+// checkRestoredState verifies the scalar state survived the round trip.
+func checkRestoredState(t *testing.T, g, h *RogueGame) {
+	t.Helper()
+
 	if h.Player.Purse != 123 || h.Player.FoodLeft != 777 {
 		t.Errorf("player state lost: purse=%d food=%d",
 			h.Player.Purse, h.Player.FoodLeft)
 	}
+
 	if !h.HasAmulet {
 		t.Error("amulet flag lost")
 	}
-	if !h.Items.Potions[PHealing].Know {
+
+	if !h.Items.Potions[PotionHealing].Know {
 		t.Error("potion identification lost")
 	}
-	if h.Items.Scrolls[SMap].Guess != "map???" {
+
+	if h.Items.Scrolls[ScrollMagicMapping].Guess != "map???" {
 		t.Error("scroll guess lost")
 	}
-	if h.Monsters['F'-'A'].Stats.Dmg != "3x1" {
+
+	if h.Monsters['F'-'A'].Stats.Dmg.String() != "3x1" {
 		t.Error("mutated bestiary lost")
 	}
+
 	if h.Rng.Seed != g.Rng.Seed {
 		t.Error("RNG state lost")
 	}
+
 	if renderMap(h) != renderMap(g) {
 		t.Error("restored level map differs")
 	}
+}
+
+// checkRestoredMonsters verifies the monster list and its pointer fixups
+// survived the round trip.
+func checkRestoredMonsters(t *testing.T, g, h *RogueGame) {
+	t.Helper()
+
 	if len(h.Level.Monsters) != len(g.Level.Monsters) {
 		t.Fatalf("monster count %d != %d",
 			len(h.Level.Monsters), len(g.Level.Monsters))
 	}
-	if len(g.Level.Monsters) > 0 {
-		m := h.Level.Monsters[0]
-		if m.Dest != &h.Player.Pos {
-			t.Error("monster chase target not re-aliased to the hero")
-		}
-		if h.Level.MonsterAt(m.Pos.Y, m.Pos.X) != m {
-			t.Error("map monster index not rebuilt")
-		}
-		if m.Room == nil {
-			t.Error("monster room pointer not rebuilt")
-		}
+
+	if len(g.Level.Monsters) == 0 {
+		return
 	}
-	// Equipment aliasing: the wielded mace must be the same *Object as the
-	// one in the pack.
+
+	m := h.Level.Monsters[0]
+	if m.Dest != &h.Player.Pos {
+		t.Error("monster chase target not re-aliased to the hero")
+	}
+
+	if h.Level.MonsterAt(m.Pos.Y, m.Pos.X) != m {
+		t.Error("map monster index not rebuilt")
+	}
+
+	if m.Room == nil {
+		t.Error("monster room pointer not rebuilt")
+	}
+}
+
+// checkEquipmentAliasing verifies the wielded mace is the same *Object as
+// the one in the pack.
+func checkEquipmentAliasing(t *testing.T, g, h *RogueGame) {
+	t.Helper()
+
 	st := g.snapshot()
 	t.Logf("snapshot indices: weapon=%d armor=%d rings=%v packlen=%d",
 		st.Player.CurWeapon, st.Player.CurArmor, st.Player.CurRing,
 		len(st.Player.Body.Pack))
 	t.Logf("restored: CurWeapon=%p pack has %d items", h.Player.CurWeapon,
 		len(h.Player.Pack))
+
 	found := false
+
 	for i, o := range h.Player.Pack {
-		t.Logf("  pack[%d]=%p type=%c which=%d", i, o, o.Type, o.Which)
+		t.Logf("  pack[%d]=%p type=%v which=%d", i, o, o.Kind, o.Which)
+
 		if o == h.Player.CurWeapon {
 			found = true
 		}
 	}
+
 	if !found {
 		t.Error("restored CurWeapon is not aliased into the pack")
 	}
@@ -98,15 +138,24 @@ func TestRestoreRejectsWrongVersion(t *testing.T) {
 	path := filepath.Join(t.TempDir(), "rogue.save")
 	st := g.snapshot()
 	st.Version = "0.0.0"
-	f, err := os.Create(path)
+
+	f, err := os.Create(path) //nolint:gosec // G304: test temp path
 	if err != nil {
 		t.Fatal(err)
 	}
-	if err := gob.NewEncoder(f).Encode(st); err != nil {
-		t.Fatal(err)
+
+	encErr := gob.NewEncoder(f).Encode(st)
+	if encErr != nil {
+		t.Fatal(encErr)
 	}
-	f.Close()
-	if _, err := Restore(path, Config{}); err == nil {
+
+	closeErr := f.Close()
+	if closeErr != nil {
+		t.Fatal(closeErr)
+	}
+
+	_, restoreErr := Restore(path, Params{})
+	if restoreErr == nil {
 		t.Error("restore accepted an out-of-date save")
 	}
 }

game/score.go

@@ -25,29 +25,28 @@ type ScoreEnt struct {
 	Time    int64
 }
 
-var scoreReasons = [4]string{
-	"killed",
-	"quit",
-	"A total winner",
-	"killed with Amulet",
-}
-
 // rdScore reads the scoreboard file (save.c rd_score).
 func (g *RogueGame) rdScore() []ScoreEnt {
 	topTen := make([]ScoreEnt, numScores)
 	if g.ScorePath == "" {
 		return topTen
 	}
+
 	f, err := os.Open(g.ScorePath)
 	if err != nil {
 		return topTen
 	}
-	defer f.Close()
+	defer func() { _ = f.Close() }() // read-only handle
+
 	var onDisk []ScoreEnt
-	if err := gob.NewDecoder(f).Decode(&onDisk); err != nil {
-		return topTen
+
+	decErr := gob.NewDecoder(f).Decode(&onDisk)
+	if decErr != nil {
+		return topTen // unreadable scoreboard reads as empty, as in C
 	}
+
 	copy(topTen, onDisk)
+
 	return topTen
 }
 
@@ -57,29 +56,45 @@ func (g *RogueGame) wrScore(topTen []ScoreEnt) {
 		return
 	}
 	// lock_sc/unlock_sc: exclusive-create lock file with stale takeover.
+	// The whole scoreboard write is best effort, as it was in C: a shared
+	// scoreboard must never take the game down.
 	lock := g.ScorePath + ".lck"
 	for range 5 {
-		lf, err := os.OpenFile(lock, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0o644)
+		lf, err := os.OpenFile(lock, //nolint:gosec // G304: configured path
+			os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0o600)
 		if err == nil {
-			lf.Close()
-			defer os.Remove(lock)
+			_ = lf.Close()
+
+			defer func() { _ = os.Remove(lock) }()
+
 			break
 		}
-		if fi, serr := os.Stat(lock); serr == nil &&
-			time.Since(fi.ModTime()) > 10*time.Second {
-			os.Remove(lock)
+
+		fi, statErr := os.Stat(lock)
+		if statErr == nil && time.Since(fi.ModTime()) > staleLockAge {
+			_ = os.Remove(lock)
+
 			continue
 		}
+
 		time.Sleep(time.Second)
 	}
-	f, err := os.OpenFile(g.ScorePath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o644)
+
+	f, err := os.OpenFile(g.ScorePath,
+		os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o600)
 	if err != nil {
 		return
 	}
-	defer f.Close()
-	gob.NewEncoder(f).Encode(topTen)
+
+	_ = gob.NewEncoder(f).Encode(topTen)
+	_ = f.Close()
 }
 
+// staleLockAge is how old a scoreboard lock file may be before another
+// process assumes its owner died and takes it over (mach_dep.c lock_sc
+// aged its lock the same way).
+const staleLockAge = 10 * time.Second
+
 // score figures the score and posts it (rip.c score). flags -1 means just
 // display the list (the -s command line option).
 func (g *RogueGame) score(amount, flags int, monst byte) {
@@ -93,94 +108,11 @@ func (g *RogueGame) score(amount, flags int, monst byte) {
 	// Insert her in list if need be
 	ins := -1
 	if !g.NoScore && flags >= 0 {
-		uid := os.Getuid()
-		scp := len(topTen)
-		for i := range topTen {
-			if amount > topTen[i].Score {
-				scp = i
-				break
-			} else if !g.AllScore && flags != 2 &&
-				topTen[i].UID == uid && topTen[i].Flags != 2 {
-				// only one score per nowin uid
-				scp = len(topTen)
-				break
-			}
-		}
-		if scp < len(topTen) {
-			sc2 := len(topTen) - 1
-			if flags != 2 && !g.AllScore {
-				for i := scp; i < len(topTen); i++ {
-					if topTen[i].UID == uid && topTen[i].Flags != 2 {
-						sc2 = i
-						break
-					}
-				}
-			}
-			for sc2 > scp {
-				topTen[sc2] = topTen[sc2-1]
-				sc2--
-			}
-			lvl := g.Depth
-			if flags == 2 {
-				lvl = g.MaxDepth
-			}
-			topTen[scp] = ScoreEnt{
-				UID:     uid,
-				Score:   amount,
-				Flags:   flags,
-				Monster: monst,
-				Name:    g.Whoami,
-				Level:   lvl,
-				Time:    time.Now().Unix(),
-			}
-			ins = scp
-		}
+		ins = g.scoreInsert(topTen, amount, flags, monst)
 	}
 
-	// Build the list display
-	label := "Rogueists"
-	if g.AllScore {
-		label = "Scores"
-	}
-	lines := []string{
-		fmt.Sprintf("Top Ten %s:", label),
-		"   Score Name",
-	}
-	highlight := -1
-	for i := range topTen {
-		scp := &topTen[i]
-		if scp.Score == 0 {
-			break
-		}
-		line := fmt.Sprintf("%2d %5d %s: %s on level %d", i+1,
-			scp.Score, scp.Name, scoreReasons[scp.Flags], scp.Level)
-		if scp.Flags == 0 || scp.Flags == 3 {
-			line += fmt.Sprintf(" by %s", g.killname(scp.Monster, true))
-		}
-		line += "."
-		if i == ins {
-			highlight = len(lines)
-		}
-		lines = append(lines, line)
-	}
-
-	if g.scr != nil && g.scr.term != nil {
-		g.clear()
-		for i, line := range lines {
-			if i == highlight {
-				g.standout()
-			}
-			g.mvaddstr(i, 0, line)
-			if i == highlight {
-				g.standend()
-			}
-		}
-		g.refresh()
-	} else {
-		for _, line := range lines {
-			fmt.Println(line)
-		}
-	}
+	lines, highlight := g.scoreLines(topTen, ins)
+	g.showScores(lines, highlight)
 
 	// Update the list file
 	if ins >= 0 {
@@ -188,6 +120,136 @@ func (g *RogueGame) score(amount, flags int, monst byte) {
 	}
 }
 
+// scoreInsert slots the new score into the top ten, honoring the
+// one-score-per-losing-uid rule; -1 means it did not place (the
+// insertion half of rip.c score).
+func (g *RogueGame) scoreInsert(topTen []ScoreEnt, amount, flags int, monst byte) int {
+	uid := os.Getuid()
+
+	scp := g.scoreSlot(topTen, amount, flags, uid)
+	if scp >= len(topTen) {
+		return -1
+	}
+
+	sc2 := len(topTen) - 1
+	if flags != 2 && !g.AllScore {
+		for i := scp; i < len(topTen); i++ {
+			if topTen[i].UID == uid && topTen[i].Flags != 2 {
+				sc2 = i
+
+				break
+			}
+		}
+	}
+
+	for sc2 > scp {
+		topTen[sc2] = topTen[sc2-1]
+		sc2--
+	}
+
+	lvl := g.Depth
+	if flags == 2 {
+		lvl = g.MaxDepth
+	}
+
+	topTen[scp] = ScoreEnt{
+		UID:     uid,
+		Score:   amount,
+		Flags:   flags,
+		Monster: monst,
+		Name:    g.Whoami,
+		Level:   lvl,
+		Time:    time.Now().Unix(),
+	}
+
+	return scp
+}
+
+// scoreSlot finds where the new score lands: len(topTen) when it does
+// not place, or when this uid already holds a losing score (the scan of
+// rip.c score).
+func (g *RogueGame) scoreSlot(topTen []ScoreEnt, amount, flags, uid int) int {
+	for i := range topTen {
+		if amount > topTen[i].Score {
+			return i
+		}
+
+		if !g.AllScore && flags != 2 &&
+			topTen[i].UID == uid && topTen[i].Flags != 2 {
+			// only one score per nowin uid
+			return len(topTen)
+		}
+	}
+
+	return len(topTen)
+}
+
+// scoreLines formats the scoreboard, noting which display line holds
+// the freshly inserted score (the display half of rip.c score).
+func (g *RogueGame) scoreLines(topTen []ScoreEnt, ins int) ([]string, int) {
+	label := "Rogueists"
+	if g.AllScore {
+		label = "Scores"
+	}
+
+	lines := []string{
+		fmt.Sprintf("Top Ten %s:", label),
+		"   Score Name",
+	}
+	highlight := -1
+
+	for i := range topTen {
+		scp := &topTen[i]
+		if scp.Score == 0 {
+			break
+		}
+
+		line := fmt.Sprintf("%2d %5d %s: %s on level %d", i+1,
+			scp.Score, scp.Name, g.data.scoreReasons[scp.Flags], scp.Level)
+		if scp.Flags == 0 || scp.Flags == 3 {
+			line += " by " + g.killname(scp.Monster, true)
+		}
+
+		line += "."
+
+		if i == ins {
+			highlight = len(lines)
+		}
+
+		lines = append(lines, line)
+	}
+
+	return lines, highlight
+}
+
+// showScores prints the scoreboard on the screen when there is one,
+// else to standard output (rip.c score).
+func (g *RogueGame) showScores(lines []string, highlight int) {
+	if g.scr == nil || g.scr.term == nil {
+		for _, line := range lines {
+			_, _ = fmt.Fprintln(os.Stdout, line) // CLI output
+		}
+
+		return
+	}
+
+	g.clear()
+
+	for i, line := range lines {
+		if i == highlight {
+			g.standout()
+		}
+
+		g.mvaddstr(i, 0, line)
+
+		if i == highlight {
+			g.standend()
+		}
+	}
+
+	g.refresh()
+}
+
 // ShowScores implements the -s command line option: print the scoreboard
 // and nothing else.
 func (g *RogueGame) ShowScores() {

game/screen.go

@@ -16,6 +16,9 @@ type Terminal interface {
 	// ReadChar blocks for the next key, translated to Rogue's input bytes
 	// (arrows become hjkl, control keys their C0 codes).
 	ReadChar() byte
+	// Fini restores the device to its pre-game state (curses endwin). The
+	// game calls it on its way out, since one game run is one process.
+	Fini()
 }
 
 // cell is one screen position.
@@ -37,26 +40,28 @@ type Window struct {
 func NewWindow(rows, cols int) *Window {
 	w := &Window{rows: rows, cols: cols, cells: make([]cell, rows*cols)}
 	w.Clear()
+
 	return w
 }
 
-func (w *Window) at(y, x int) *cell { return &w.cells[y*w.cols+x] }
-
 // Move positions the cursor (curses move/wmove).
 func (w *Window) Move(y, x int) { w.cy, w.cx = y, x }
 
 // GetYX reports the cursor position (curses getyx).
-func (w *Window) GetYX() (y, x int) { return w.cy, w.cx }
+func (w *Window) GetYX() (int, int) { return w.cy, w.cx }
 
 // AddCh writes a character at the cursor and advances it (curses addch).
 func (w *Window) AddCh(ch byte) {
 	if ch == '\n' {
 		w.cy, w.cx = w.cy+1, 0
+
 		return
 	}
+
 	if w.cy < 0 || w.cy >= w.rows || w.cx < 0 || w.cx >= w.cols {
 		return
 	}
+
 	*w.at(w.cy, w.cx) = cell{ch: ch, standout: w.standout}
 	if w.cx++; w.cx >= w.cols {
 		w.cx = 0
@@ -68,7 +73,7 @@ func (w *Window) AddCh(ch byte) {
 
 // AddStr writes a string at the cursor (curses addstr).
 func (w *Window) AddStr(s string) {
-	for i := 0; i < len(s); i++ {
+	for i := range len(s) {
 		w.AddCh(s[i])
 	}
 }
@@ -85,15 +90,15 @@ func (w *Window) MvAddStr(y, x int, s string) {
 	w.AddStr(s)
 }
 
-// Printw writes formatted text at the cursor (curses printw).
-func (w *Window) Printw(format string, a ...any) {
+// Printwf writes formatted text at the cursor (curses printw).
+func (w *Window) Printwf(format string, a ...any) {
 	w.AddStr(fmt.Sprintf(format, a...))
 }
 
-// MvPrintw moves then writes formatted text (curses mvprintw).
-func (w *Window) MvPrintw(y, x int, format string, a ...any) {
+// MvPrintwf moves then writes formatted text (curses mvprintw).
+func (w *Window) MvPrintwf(y, x int, format string, a ...any) {
 	w.Move(y, x)
-	w.Printw(format, a...)
+	w.Printwf(format, a...)
 }
 
 // Inch returns the character under the cursor (curses inch, sans
@@ -102,12 +107,14 @@ func (w *Window) Inch() byte {
 	if w.cy < 0 || w.cy >= w.rows || w.cx < 0 || w.cx >= w.cols {
 		return ' '
 	}
+
 	return w.at(w.cy, w.cx).ch
 }
 
 // MvInch moves then reads (curses mvinch).
 func (w *Window) MvInch(y, x int) byte {
 	w.Move(y, x)
+
 	return w.Inch()
 }
 
@@ -120,6 +127,7 @@ func (w *Window) Clear() {
 	for i := range w.cells {
 		w.cells[i] = cell{ch: ' '}
 	}
+
 	w.cy, w.cx = 0, 0
 }
 
@@ -128,6 +136,7 @@ func (w *Window) Clrtoeol() {
 	if w.cy < 0 || w.cy >= w.rows {
 		return
 	}
+
 	for x := w.cx; x < w.cols; x++ {
 		*w.at(w.cy, x) = cell{ch: ' '}
 	}
@@ -138,13 +147,14 @@ func (w *Window) CopyFrom(src *Window) {
 	copy(w.cells, src.cells)
 }
 
-// Size reports the window dimensions.
-func (w *Window) Size() (rows, cols int) { return w.rows, w.cols }
+// Size reports the window dimensions as rows, columns.
+func (w *Window) Size() (int, int) { return w.rows, w.cols }
 
 // CellAt reports the character and standout attribute at a position; used
 // by Terminal implementations to render the window.
-func (w *Window) CellAt(y, x int) (ch byte, standout bool) {
+func (w *Window) CellAt(y, x int) (byte, bool) {
 	c := w.at(y, x)
+
 	return c.ch, c.standout
 }
 
@@ -155,6 +165,7 @@ func (w *Window) Contents() []byte {
 	for i, c := range w.cells {
 		out[i] = c.ch
 	}
+
 	return out
 }
 
@@ -171,12 +182,16 @@ func (w *Window) SetContents(data []byte) {
 // victory screens.
 func (w *Window) Line(y int) string {
 	buf := make([]byte, w.cols)
-	for x := 0; x < w.cols; x++ {
+	for x := range w.cols {
 		buf[x] = w.at(y, x).ch
 	}
+
 	return string(buf)
 }
 
+// at addresses the cell at (y, x) in the backing array.
+func (w *Window) at(y, x int) *cell { return &w.cells[y*w.cols+x] }
+
 // Screen bundles the two windows the game draws on with the device that
 // shows them.
 type Screen struct {
@@ -201,6 +216,13 @@ func (s *Screen) Refresh() {
 	}
 }
 
+// Fini restores the terminal device, if there is one (curses endwin).
+func (s *Screen) Fini() {
+	if s.term != nil {
+		s.term.Fini()
+	}
+}
+
 // RefreshWin pushes an arbitrary window to the device (curses wrefresh).
 func (s *Screen) RefreshWin(w *Window) {
 	if s.term != nil {
@@ -217,7 +239,7 @@ func (g *RogueGame) mvaddch(y, x int, c byte) { g.scr.Std.MvAddCh(y, x, c) }
 func (g *RogueGame) mvaddstr(y, x int, s string) {
 	g.scr.Std.MvAddStr(y, x, s)
 }
-func (g *RogueGame) printw(f string, a ...any) { g.scr.Std.Printw(f, a...) }
+func (g *RogueGame) printw(f string, a ...any) { g.scr.Std.Printwf(f, a...) }
 func (g *RogueGame) inch() byte                { return g.scr.Std.Inch() }
 func (g *RogueGame) mvinch(y, x int) byte      { return g.scr.Std.MvInch(y, x) }
 func (g *RogueGame) standout()                 { g.scr.Std.Standout(true) }

game/scrolls.go

@@ -2,30 +2,23 @@ package game
 
 // scrolls.c — read a scroll and let it happen.
 
-// idType maps identify scrolls to the type they identify (scrolls.c
-// static id_type).
-var idType = [SIDRorS + 1]int{
-	SIDPotion: int(Potion),
-	SIDScroll: int(Scroll),
-	SIDWeapon: int(Weapon),
-	SIDArmor:  int(Armor),
-	SIDRorS:   RorS,
-}
-
 // readScroll reads a scroll from the pack and does the appropriate thing
 // (scrolls.c read_scroll).
 func (g *RogueGame) readScroll() {
 	p := &g.Player
-	obj := g.getItem("read", int(Scroll))
-	if obj == nil {
+
+	obj, ok := g.promptPackItem("read", KindScroll)
+	if !ok {
 		return
 	}
-	if obj.Type != Scroll {
+
+	if obj.Kind != KindScroll {
 		if !g.Options.Terse {
 			g.msg("there is nothing on it to read")
 		} else {
 			g.msg("nothing to read")
 		}
+
 		return
 	}
 	// Calculate the effect it has on the poor guy.
@@ -35,228 +28,346 @@ func (g *RogueGame) readScroll() {
 	// Get rid of the thing
 	g.leavePack(obj, false, false)
 
-	switch obj.Which {
-	case SConfuse:
-		// Scroll of monster confusion.  Give him that power.
-		p.Flags.Set(CanHuh)
-		g.msg("your hands begin to glow %s", g.pickColor("red"))
-	case SArmor:
-		if p.CurArmor != nil {
-			p.CurArmor.Arm--
-			p.CurArmor.Flags.Clear(IsCursed)
-			g.msg("your armor glows %s for a moment", g.pickColor("silver"))
-		}
-	case SHold:
-		// Hold monster scroll.  Stop all monsters within two spaces from
-		// chasing after the hero.
-		held := 0
-		for x := p.Pos.X - 2; x <= p.Pos.X+2; x++ {
-			if x < 0 || x >= NumCols {
-				continue
-			}
-			for y := p.Pos.Y - 2; y <= p.Pos.Y+2; y++ {
-				if y < 0 || y > NumLines-1 {
-					continue
-				}
-				if mp := g.Level.MonsterAt(y, x); mp != nil && mp.On(IsRun) {
-					mp.Flags.Clear(IsRun)
-					mp.Flags.Set(IsHeld)
-					held++
-				}
-			}
-		}
-		if held > 0 {
-			g.addmsg("the monster")
-			if held > 1 {
-				g.addmsg("s around you")
-			}
-			g.addmsg(" freeze")
-			if held == 1 {
-				g.addmsg("s")
-			}
-			g.endmsg()
-			g.Items.Scrolls[SHold].Know = true
-		} else {
-			g.msg("you feel a strange sense of loss")
-		}
-	case SSleep:
-		// Scroll which makes you fall asleep
-		g.Items.Scrolls[SSleep].Know = true
-		g.NoCommand += g.rnd(g.spread(5)) + 4 // SLEEPTIME
-		p.Flags.Clear(IsRun)
-		g.msg("you fall asleep")
-	case SCreate:
-		// Create a monster: first look in a circle around him, next try
-		// his room, otherwise give up
-		i := 0
-		var mp Coord
-		for y := p.Pos.Y - 1; y <= p.Pos.Y+1; y++ {
-			for x := p.Pos.X - 1; x <= p.Pos.X+1; x++ {
-				// Don't put a monster on top of the player.
-				if y == p.Pos.Y && x == p.Pos.X {
-					continue
-				}
-				// Or anything else nasty
-				if ch := g.Level.VisibleChar(y, x); stepOk(ch) {
-					if ch == Scroll {
-						if fo := g.findObj(y, x); fo != nil && fo.Which == SScare {
-							continue
-						}
-					}
-					if i++; g.rnd(i) == 0 {
-						mp = Coord{Y: y, X: x}
-					}
-				}
-			}
-		}
-		if i == 0 {
-			g.msg("you hear a faint cry of anguish in the distance")
-		} else {
-			tp := &Monster{}
-			g.newMonster(tp, g.randMonster(false), mp)
-		}
-	case SIDPotion, SIDScroll, SIDWeapon, SIDArmor, SIDRorS:
-		// Identify, let him figure something out
-		g.Items.Scrolls[obj.Which].Know = true
-		g.msg("this scroll is an %s scroll", g.Items.Scrolls[obj.Which].Name)
-		g.whatis(true, idType[obj.Which])
-	case SMap:
-		// Scroll of magic mapping.
-		g.Items.Scrolls[SMap].Know = true
-		g.msg("oh, now this scroll has a map on it")
-		// take all the things we want to keep hidden out of the window
-		for y := 1; y < NumLines-1; y++ {
-			for x := 0; x < NumCols; x++ {
-				pp := g.Level.At(y, x)
-				ch := pp.Ch
-				pass := false
-				switch ch {
-				case Door, Stairs:
-				case '-', '|':
-					if !pp.Flags.Has(FReal) {
-						ch = Door
-						pp.Ch = Door
-						pp.Flags.Set(FReal)
-					}
-				case ' ':
-					if pp.Flags.Has(FReal) {
-						// def: hidden things in walls stay hidden
-						if pp.Flags.Has(FPass) {
-							pass = true
-						} else {
-							ch = ' '
-						}
-					} else {
-						pp.Flags.Set(FReal)
-						pp.Ch = Passage
-						pass = true
-					}
-				case Passage:
-					pass = true
-				case Floor:
-					if pp.Flags.Has(FReal) {
-						ch = ' '
-					} else {
-						ch = Trap
-						pp.Ch = Trap
-						pp.Flags.Set(FSeen | FReal)
-					}
-				default:
-					if pp.Flags.Has(FPass) {
-						pass = true
-					} else {
-						ch = ' '
-					}
-				}
-				if pass {
-					if !pp.Flags.Has(FReal) {
-						pp.Ch = Passage
-					}
-					pp.Flags.Set(FSeen | FReal)
-					ch = Passage
-				}
-				if ch != ' ' {
-					if tp := pp.Monst; tp != nil {
-						tp.OldCh = ch
-						if !p.On(SeeMonst) {
-							g.mvaddch(y, x, ch)
-						}
-					} else {
-						g.mvaddch(y, x, ch)
-					}
-				}
-			}
-		}
-	case SFDet:
-		// Food detection
-		found := false
-		g.scr.Hw.Clear()
-		for _, fo := range g.Level.Objects {
-			if fo.Type == Food {
-				found = true
-				g.scr.Hw.MvAddCh(fo.Pos.Y, fo.Pos.X, Food)
-			}
-		}
-		if found {
-			g.Items.Scrolls[SFDet].Know = true
-			g.showWin("Your nose tingles and you smell food.--More--")
-		} else {
-			g.msg("your nose tingles")
-		}
-	case STelep:
-		// Scroll of teleportation: make him disappear and reappear
-		curRoom := p.Room
-		g.teleport()
-		if curRoom != p.Room {
-			g.Items.Scrolls[STelep].Know = true
-		}
-	case SEnch:
-		if p.CurWeapon == nil || p.CurWeapon.Type != Weapon {
-			g.msg("you feel a strange sense of loss")
-		} else {
-			p.CurWeapon.Flags.Clear(IsCursed)
-			if g.rnd(2) == 0 {
-				p.CurWeapon.HPlus++
-			} else {
-				p.CurWeapon.DPlus++
-			}
-			g.msg("your %s glows %s for a moment",
-				g.Items.Weapons[p.CurWeapon.Which].Name, g.pickColor("blue"))
-		}
-	case SScare:
-		// Reading it is a mistake and produces laughter at her poor boo
-		// boo.
-		g.msg("you hear maniacal laughter in the distance")
-	case SRemove:
-		uncurse(p.CurArmor)
-		uncurse(p.CurWeapon)
-		uncurse(p.CurRing[Left])
-		uncurse(p.CurRing[Right])
-		g.msg("%s", g.chooseStr("you feel in touch with the Universal Onenes",
-			"you feel as if somebody is watching over you"))
-	case SAggr:
-		// This scroll aggravates all the monsters on the current level
-		// and sets them running towards the hero
-		g.aggravate()
-		g.msg("you hear a high pitched humming noise")
-	case SProtect:
-		if p.CurArmor != nil {
-			p.CurArmor.Flags.Set(IsProt)
-			g.msg("your armor is covered by a shimmering %s shield",
-				g.pickColor("gold"))
-		} else {
-			g.msg("you feel a strange sense of loss")
-		}
+	if h := g.data.readHandlers[obj.ScrollKind()]; h != nil {
+		h(g, obj)
 	}
+
 	g.look(true) // put the result of the scroll on the screen
 	g.status()
 
 	g.callIt(&g.Items.Scrolls[obj.Which])
 }
 
+// The per-scroll effect handlers, dispatched through
+// gameData.readHandlers. Each is one case of the C read_scroll switch.
+
+func (g *RogueGame) readMonsterConfusion(*Object) {
+	// Scroll of monster confusion.  Give him that power.
+	g.Player.Flags.Set(CanConfuse)
+	g.msg("your hands begin to glow %s", g.pickColor("red"))
+}
+
+func (g *RogueGame) readEnchantArmor(*Object) {
+	p := &g.Player
+	if p.CurArmor != nil {
+		p.CurArmor.ArmorClass--
+		p.CurArmor.Flags.Clear(Cursed)
+		g.msg("your armor glows %s for a moment", g.pickColor("silver"))
+	}
+}
+
+func (g *RogueGame) readHoldMonster(*Object) {
+	// Hold monster scroll.  Stop all monsters within two spaces from
+	// chasing after the hero.
+	held := g.holdMonstersNear()
+
+	if held > 0 {
+		g.addmsgf("the monster")
+
+		if held > 1 {
+			g.addmsgf("s around you")
+		}
+
+		g.addmsgf(" freeze")
+
+		if held == 1 {
+			g.addmsgf("s")
+		}
+
+		g.endmsg()
+		g.Items.Scrolls[ScrollHoldMonster].Know = true
+	} else {
+		g.msg("you feel a strange sense of loss")
+	}
+}
+
+// holdMonstersNear freezes every awake monster within two spaces of the
+// hero and reports how many froze (the scan of the C S_HOLD case).
+func (g *RogueGame) holdMonstersNear() int {
+	p := &g.Player
+	held := 0
+
+	for x := p.Pos.X - 2; x <= p.Pos.X+2; x++ {
+		if x < 0 || x >= NumCols {
+			continue
+		}
+
+		for y := p.Pos.Y - 2; y <= p.Pos.Y+2; y++ {
+			if y < 0 || y > NumLines-1 {
+				continue
+			}
+
+			if mp := g.Level.MonsterAt(y, x); mp != nil && mp.On(Awake) {
+				mp.Flags.Clear(Awake)
+				mp.Flags.Set(Held)
+
+				held++
+			}
+		}
+	}
+
+	return held
+}
+
+func (g *RogueGame) readSleep(*Object) {
+	// Scroll which makes you fall asleep
+	g.Items.Scrolls[ScrollSleep].Know = true
+	g.NoCommand += g.rnd(g.spread(5)) + 4 // SLEEPTIME
+
+	g.Player.Flags.Clear(Awake)
+	g.msg("you fall asleep")
+}
+
+func (g *RogueGame) readCreateMonster(*Object) {
+	// Create a monster: first look in a circle around him, next try
+	// his room, otherwise give up
+	mp, ok := g.createMonsterSpot()
+	if !ok {
+		g.msg("you hear a faint cry of anguish in the distance")
+	} else {
+		tp := &Monster{}
+		g.newMonster(tp, g.randMonster(false), mp)
+	}
+}
+
+// createMonsterSpot reservoir-samples a legal spot around the hero for a
+// created monster; ok is false when every neighbor is blocked (the scan
+// of the C S_CREATE case).
+func (g *RogueGame) createMonsterSpot() (Coord, bool) {
+	p := &g.Player
+	i := 0
+
+	var mp Coord
+
+	for y := p.Pos.Y - 1; y <= p.Pos.Y+1; y++ {
+		for x := p.Pos.X - 1; x <= p.Pos.X+1; x++ {
+			// Don't put a monster on top of the player.
+			if y == p.Pos.Y && x == p.Pos.X {
+				continue
+			}
+			// Or anything else nasty
+			if ch := g.Level.VisibleChar(y, x); stepOk(ch) {
+				if ch == Scroll {
+					if fo := g.Level.ObjectAt(y, x); fo != nil && fo.ScrollKind() == ScrollScareMonster {
+						continue
+					}
+				}
+
+				if i++; g.rnd(i) == 0 {
+					mp = Coord{Y: y, X: x}
+				}
+			}
+		}
+	}
+
+	return mp, i != 0
+}
+
+func (g *RogueGame) readIdentify(obj *Object) {
+	// Identify, let him figure something out
+	g.Items.Scrolls[obj.Which].Know = true
+	g.msg("this scroll is an %s scroll", g.Items.Scrolls[obj.Which].Name)
+	g.whatis(true, g.data.idType[obj.ScrollKind()])
+}
+
+func (g *RogueGame) readMagicMapping(*Object) {
+	// Scroll of magic mapping.
+	g.Items.Scrolls[ScrollMagicMapping].Know = true
+	g.msg("oh, now this scroll has a map on it")
+	// take all the things we want to keep hidden out of the window
+	for y := 1; y < NumLines-1; y++ {
+		for x := range NumCols {
+			g.revealSpot(y, x)
+		}
+	}
+}
+
+// revealSpot uncovers one map cell for magic mapping and draws it (the
+// loop body of the C SCR_MAP case).
+func (g *RogueGame) revealSpot(y, x int) {
+	pp := g.Level.At(y, x)
+
+	ch := revealChar(pp)
+	if ch != ' ' {
+		if tp := pp.Monst; tp != nil {
+			tp.OldCh = ch
+			if !g.Player.On(SenseMonsters) {
+				g.mvaddch(y, x, ch)
+			}
+		} else {
+			g.mvaddch(y, x, ch)
+		}
+	}
+}
+
+// revealChar decides what magic mapping shows at a cell, making secret
+// doors, hidden passages, and hidden traps real as a side effect; ' '
+// means show nothing (the switch of the C SCR_MAP loop).
+func revealChar(pp *Place) byte {
+	ch := pp.Ch
+	pass := false
+
+	switch ch {
+	case Door, Stairs:
+	case '-', '|':
+		ch = revealWall(pp)
+	case ' ':
+		pass = revealSolid(pp)
+	case Passage:
+		pass = true
+	case Floor:
+		ch = revealFloor(pp)
+	default:
+		if pp.Flags.Has(FPassage) {
+			pass = true
+		} else {
+			ch = ' '
+		}
+	}
+
+	if pass {
+		if !pp.Flags.Has(FReal) {
+			pp.Ch = Passage
+		}
+
+		pp.Flags.Set(FSeen | FReal)
+
+		ch = Passage
+	}
+
+	return ch
+}
+
+// revealWall handles a wall cell for magic mapping: a secret door
+// becomes a real door (the '-'/'|' arm).
+func revealWall(pp *Place) byte {
+	if !pp.Flags.Has(FReal) {
+		pp.Ch = Door
+		pp.Flags.Set(FReal)
+
+		return Door
+	}
+
+	return pp.Ch
+}
+
+// revealSolid handles a blank cell for magic mapping, reporting whether
+// it is passage: hidden passages become real; hidden things in walls
+// stay hidden (the ' ' arm).
+func revealSolid(pp *Place) bool {
+	if pp.Flags.Has(FReal) {
+		return pp.Flags.Has(FPassage)
+	}
+
+	pp.Flags.Set(FReal)
+	pp.Ch = Passage
+
+	return true
+}
+
+// revealFloor handles a floor cell for magic mapping: a hidden trap
+// becomes a real, seen trap; real floor shows nothing (the FLOOR arm).
+func revealFloor(pp *Place) byte {
+	if pp.Flags.Has(FReal) {
+		return ' '
+	}
+
+	pp.Ch = Trap
+	pp.Flags.Set(FSeen | FReal)
+
+	return Trap
+}
+
+func (g *RogueGame) readFoodDetection(*Object) {
+	// Food detection
+	found := false
+
+	g.scr.Hw.Clear()
+
+	for _, fo := range g.Level.Objects {
+		if fo.Kind == KindFood {
+			found = true
+
+			g.scr.Hw.MvAddCh(fo.Pos.Y, fo.Pos.X, Food)
+		}
+	}
+
+	if found {
+		g.Items.Scrolls[ScrollFoodDetection].Know = true
+		g.showWin("Your nose tingles and you smell food.--More--")
+	} else {
+		g.msg("your nose tingles")
+	}
+}
+
+func (g *RogueGame) readTeleportation(*Object) {
+	// Scroll of teleportation: make him disappear and reappear
+	p := &g.Player
+	curRoom := p.Room
+
+	g.teleport()
+
+	if curRoom != p.Room {
+		g.Items.Scrolls[ScrollTeleportation].Know = true
+	}
+}
+
+func (g *RogueGame) readEnchantWeapon(*Object) {
+	p := &g.Player
+	if p.CurWeapon == nil || p.CurWeapon.Kind != KindWeapon {
+		g.msg("you feel a strange sense of loss")
+	} else {
+		p.CurWeapon.Flags.Clear(Cursed)
+
+		if g.rnd(2) == 0 {
+			p.CurWeapon.HPlus++
+		} else {
+			p.CurWeapon.DPlus++
+		}
+
+		g.msg("your %s glows %s for a moment",
+			g.Items.Weapons[p.CurWeapon.Which].Name, g.pickColor("blue"))
+	}
+}
+
+func (g *RogueGame) readScareMonster(*Object) {
+	// Reading it is a mistake and produces laughter at her poor boo
+	// boo.
+	g.msg("you hear maniacal laughter in the distance")
+}
+
+func (g *RogueGame) readRemoveCurse(*Object) {
+	p := &g.Player
+
+	uncurse(p.CurArmor)
+	uncurse(p.CurWeapon)
+	uncurse(p.CurRing[Left])
+	uncurse(p.CurRing[Right])
+	g.msg("%s", g.chooseStr("you feel in touch with the Universal Onenes",
+		"you feel as if somebody is watching over you"))
+}
+
+func (g *RogueGame) readAggravateMonsters(*Object) {
+	// This scroll aggravates all the monsters on the current level
+	// and sets them running towards the hero
+	g.aggravate()
+	g.msg("you hear a high pitched humming noise")
+}
+
+func (g *RogueGame) readProtectArmor(*Object) {
+	p := &g.Player
+	if p.CurArmor != nil {
+		p.CurArmor.Flags.Set(Protected)
+		g.msg("your armor is covered by a shimmering %s shield",
+			g.pickColor("gold"))
+	} else {
+		g.msg("you feel a strange sense of loss")
+	}
+}
+
 // uncurse uncurses an item (scrolls.c uncurse).
 func uncurse(obj *Object) {
 	if obj != nil {
-		obj.Flags.Clear(IsCursed)
+		obj.Flags.Clear(Cursed)
 	}
 }

game/seedcompat_test.go

@@ -0,0 +1,98 @@
+package game
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"testing"
+)
+
+// dumpItemTables formats a game's per-seed item appearance tables in the
+// same layout the instrumented C reference prints: the potion colors,
+// scroll names, ring stones, and wand/staff materials, each generated by
+// consuming the RNG in a fixed order during New().
+func dumpItemTables(seed int32, g *RogueGame) string {
+	var b strings.Builder
+
+	fmt.Fprintf(&b, "SEED %d\n", seed)
+
+	fmt.Fprintln(&b, "POTIONS")
+
+	for _, c := range g.Items.PotColors {
+		fmt.Fprintln(&b, c)
+	}
+
+	fmt.Fprintln(&b, "SCROLLS")
+
+	for _, s := range g.Items.ScrNames {
+		fmt.Fprintln(&b, s)
+	}
+
+	fmt.Fprintln(&b, "RINGS")
+
+	for _, s := range g.Items.RingStones {
+		fmt.Fprintln(&b, s)
+	}
+
+	fmt.Fprintln(&b, "STICKS")
+
+	for i := range g.Items.WandType {
+		fmt.Fprintf(&b, "%s %s\n", g.Items.WandType[i], g.Items.WandMade[i])
+	}
+
+	return b.String()
+}
+
+// TestSeedCompatItemTables proves the port's seed-compatibility claim: for
+// the same seed, the Go game generates the exact per-seed item appearance
+// tables as the C reference on modern-rogue. That requires the LCG and its
+// consumption order through the whole init sequence (init_probs →
+// init_player → init_names → init_colors → init_stones → init_materials) to
+// match C byte for byte. The golden is captured from an instrumented build
+// of the C game (testdata/README.md).
+func TestSeedCompatItemTables(t *testing.T) {
+	golden, err := os.ReadFile("testdata/item_tables.golden")
+	if err != nil {
+		t.Fatalf("read golden: %v", err)
+	}
+
+	// These must match the seeds the golden was generated from
+	// (testdata/README.md).
+	seeds := []int32{1, 42, 12345, 99999}
+
+	var got strings.Builder
+
+	for _, seed := range seeds {
+		g := New(Params{Seed: seed, Wizard: true})
+		got.WriteString(dumpItemTables(seed, g))
+	}
+
+	if got.String() != string(golden) {
+		t.Errorf("Go item tables diverge from the C reference at %s",
+			firstDiff(string(golden), got.String()))
+	}
+}
+
+// firstDiff returns a description of the first line where want and got
+// differ, for a readable failure.
+func firstDiff(want, got string) string {
+	wl := strings.Split(want, "\n")
+	gl := strings.Split(got, "\n")
+
+	for i := 0; i < len(wl) || i < len(gl); i++ {
+		w, g := "", ""
+		if i < len(wl) {
+			w = wl[i]
+		}
+
+		if i < len(gl) {
+			g = gl[i]
+		}
+
+		if w != g {
+			return fmt.Sprintf("line %d: C=%q Go=%q", i+1, w, g)
+		}
+	}
+
+	return "no line difference (trailing content?)"
+}

game/sticks.go

@@ -4,170 +4,287 @@ import "fmt"
 
 // sticks.c — zap wands and staffs.
 
+// The two ws_type strings a stick can be made as.
+const (
+	wandName  = "wand"
+	staffName = "staff"
+)
+
 // doZap performs a zap with a wand (sticks.c do_zap).
 func (g *RogueGame) doZap() {
-	p := &g.Player
-	obj := g.getItem("zap with", int(Stick))
-	if obj == nil {
+	obj, ok := g.promptPackItem("zap with", KindWand)
+	if !ok {
 		return
 	}
-	if obj.Type != Stick {
+
+	if obj.Kind != KindWand {
 		g.After = false
 		g.msg("you can't zap with that!")
+
 		return
 	}
-	if obj.Charges() == 0 {
+
+	if obj.Charges == 0 {
 		g.msg("nothing happens")
+
 		return
 	}
-	switch obj.Which {
-	case WsLight:
-		// Reddy Kilowatt wand.  Light up the room
-		g.Items.Sticks[WsLight].Know = true
-		if p.Room.Flags.Has(IsGone) {
-			g.msg("the corridor glows and then fades")
-		} else {
-			p.Room.Flags.Clear(IsDark)
-			// Light the room and put the player back up
-			g.enterRoom(p.Pos)
-			g.addmsg("the room is lit")
-			if !g.Options.Terse {
-				g.addmsg(" by a shimmering %s light", g.pickColor("blue"))
-			}
-			g.endmsg()
+
+	if h := g.data.zapHandlers[obj.WandKind()]; h != nil {
+		if !h(g, obj) {
+			return // the zap aborted; no charge is used
 		}
-	case WsDrain:
-		// take away 1/2 of hero's hit points, then take it away evenly
-		// from the monsters in the room (or next to hero if he is in a
-		// passage)
-		if p.Stats.HP < 2 {
-			g.msg("you are too weak to use it")
-			return
-		}
-		g.drain()
-	case WsInvis, WsPolymorph, WsTelAway, WsTelTo, WsCancel:
-		y := p.Pos.Y
-		x := p.Pos.X
-		for stepOk(g.Level.VisibleChar(y, x)) {
-			y += g.Delta.Y
-			x += g.Delta.X
-		}
-		if tp := g.Level.MonsterAt(y, x); tp != nil {
-			monster := tp.Type
-			if monster == 'F' {
-				p.Flags.Clear(IsHeld)
-			}
-			switch obj.Which {
-			case WsInvis:
-				tp.Flags.Set(IsInvis)
-				if g.cansee(y, x) {
-					g.mvaddch(y, x, tp.OldCh)
-				}
-			case WsPolymorph:
-				pp := tp.Pack
-				detachMon(&g.Level.Monsters, tp)
-				if g.seeMonst(tp) {
-					g.mvaddch(y, x, g.Level.Char(y, x))
-				}
-				oldch := tp.OldCh
-				g.Delta.Y = y
-				g.Delta.X = x
-				monster = byte(g.rnd(26) + 'A')
-				g.newMonster(tp, monster, g.Delta)
-				if g.seeMonst(tp) {
-					g.mvaddch(y, x, monster)
-				}
-				tp.OldCh = oldch
-				tp.Pack = pp
-				if g.seeMonst(tp) {
-					g.Items.Sticks[WsPolymorph].Know = true
-				}
-			case WsCancel:
-				tp.Flags.Set(IsCanc)
-				tp.Flags.Clear(IsInvis | CanHuh)
-				tp.Disguise = tp.Type
-				if g.seeMonst(tp) {
-					g.mvaddch(y, x, tp.Disguise)
-				}
-			case WsTelAway, WsTelTo:
-				var newPos Coord
-				if obj.Which == WsTelAway {
-					for {
-						newPos, _ = g.findFloor(nil, 0, true)
-						if newPos != p.Pos {
-							break
-						}
-					}
-				} else {
-					newPos.Y = p.Pos.Y + g.Delta.Y
-					newPos.X = p.Pos.X + g.Delta.X
-				}
-				tp.Dest = &p.Pos
-				tp.Flags.Set(IsRun)
-				g.relocate(tp, newPos)
-			}
-		}
-	case WsMissile:
-		g.Items.Sticks[WsMissile].Know = true
-		bolt := newObject()
-		bolt.Type = '*'
-		bolt.HurlDmg = "1x4"
-		bolt.HPlus = 100
-		bolt.DPlus = 1
-		bolt.Flags = IsMissl
-		if p.CurWeapon != nil {
-			bolt.Launch = p.CurWeapon.Which
-		}
-		g.doMotion(bolt, g.Delta.Y, g.Delta.X)
-		if tp := g.Level.MonsterAt(bolt.Pos.Y, bolt.Pos.X); tp != nil &&
-			!g.saveThrow(VsMagic, &tp.Stats) {
-			g.hitMonster(bolt.Pos, bolt)
-		} else if g.Options.Terse {
-			g.msg("missle vanishes")
-		} else {
-			g.msg("the missle vanishes with a puff of smoke")
-		}
-	case WsHasteM, WsSlowM:
-		y := p.Pos.Y
-		x := p.Pos.X
-		for stepOk(g.Level.VisibleChar(y, x)) {
-			y += g.Delta.Y
-			x += g.Delta.X
-		}
-		if tp := g.Level.MonsterAt(y, x); tp != nil {
-			if obj.Which == WsHasteM {
-				if tp.On(IsSlow) {
-					tp.Flags.Clear(IsSlow)
-				} else {
-					tp.Flags.Set(IsHaste)
-				}
-			} else {
-				if tp.On(IsHaste) {
-					tp.Flags.Clear(IsHaste)
-				} else {
-					tp.Flags.Set(IsSlow)
-				}
-				tp.Turn = true
-			}
-			g.Delta.Y = y
-			g.Delta.X = x
-			g.runto(g.Delta)
-		}
-	case WsElect, WsFire, WsCold:
-		var name string
-		switch obj.Which {
-		case WsElect:
-			name = "bolt"
-		case WsFire:
-			name = "flame"
-		default:
-			name = "ice"
-		}
-		g.fireBolt(p.Pos, &g.Delta, name)
-		g.Items.Sticks[obj.Which].Know = true
-	case WsNop:
 	}
-	obj.SetCharges(obj.Charges() - 1)
+
+	obj.Charges--
+}
+
+// zapRayMonster walks the zap ray from the hero to the first blocking
+// spot and returns the monster standing there, if any (the shared
+// preamble of the C monster-affecting zap cases).
+func (g *RogueGame) zapRayMonster() *Monster {
+	p := &g.Player
+
+	y := p.Pos.Y
+
+	x := p.Pos.X
+	for stepOk(g.Level.VisibleChar(y, x)) {
+		y += g.Delta.Y
+		x += g.Delta.X
+	}
+
+	return g.Level.MonsterAt(y, x)
+}
+
+// zapVictim is zapRayMonster plus the flytrap release the C code does
+// before the invisibility-family effects.
+func (g *RogueGame) zapVictim() *Monster {
+	tp := g.zapRayMonster()
+	if tp != nil && tp.Type == 'F' {
+		g.Player.Flags.Clear(Held)
+	}
+
+	return tp
+}
+
+// The per-wand effect handlers, dispatched through gameData.zapHandlers.
+// Each is one case of the C do_zap switch; returning false aborts the
+// zap without using a charge.
+
+func (g *RogueGame) zapLight(*Object) bool {
+	// Reddy Kilowatt wand.  Light up the room
+	p := &g.Player
+
+	g.Items.Sticks[WandLight].Know = true
+	if p.Room.Flags.Has(Gone) {
+		g.msg("the corridor glows and then fades")
+	} else {
+		p.Room.Flags.Clear(Dark)
+		// Light the room and put the player back up
+		g.enterRoom(p.Pos)
+		g.addmsgf("the room is lit")
+
+		if !g.Options.Terse {
+			g.addmsgf(" by a shimmering %s light", g.pickColor("blue"))
+		}
+
+		g.endmsg()
+	}
+
+	return true
+}
+
+func (g *RogueGame) zapDrainLife(*Object) bool {
+	// take away 1/2 of hero's hit points, then take it away evenly
+	// from the monsters in the room (or next to hero if he is in a
+	// passage)
+	if g.Player.Stats.HP < 2 {
+		g.msg("you are too weak to use it")
+
+		return false
+	}
+
+	g.drain()
+
+	return true
+}
+
+func (g *RogueGame) zapInvisibility(*Object) bool {
+	if tp := g.zapVictim(); tp != nil {
+		tp.Flags.Set(Invisible)
+
+		if g.canSee(tp.Pos.Y, tp.Pos.X) {
+			g.mvaddch(tp.Pos.Y, tp.Pos.X, tp.OldCh)
+		}
+	}
+
+	return true
+}
+
+func (g *RogueGame) zapPolymorph(*Object) bool {
+	tp := g.zapVictim()
+	if tp == nil {
+		return true
+	}
+
+	y, x := tp.Pos.Y, tp.Pos.X
+
+	pp := tp.Pack
+	g.Level.RemoveMonster(tp)
+
+	if g.seeMonst(tp) {
+		g.mvaddch(y, x, g.Level.Char(y, x))
+	}
+
+	oldch := tp.OldCh
+	g.Delta.Y = y
+	g.Delta.X = x
+	monster := g.randomMonsterLetter()
+	g.newMonster(tp, monster, g.Delta)
+
+	if g.seeMonst(tp) {
+		g.mvaddch(y, x, monster)
+	}
+
+	tp.OldCh = oldch
+
+	tp.Pack = pp
+	if g.seeMonst(tp) {
+		g.Items.Sticks[WandPolymorph].Know = true
+	}
+
+	return true
+}
+
+func (g *RogueGame) zapCancellation(*Object) bool {
+	if tp := g.zapVictim(); tp != nil {
+		tp.Flags.Set(Cancelled)
+		tp.Flags.Clear(Invisible | CanConfuse)
+
+		tp.Disguise = tp.Type
+		if g.seeMonst(tp) {
+			g.mvaddch(tp.Pos.Y, tp.Pos.X, tp.Disguise)
+		}
+	}
+
+	return true
+}
+
+func (g *RogueGame) zapTeleport(obj *Object) bool {
+	p := &g.Player
+
+	tp := g.zapVictim()
+	if tp == nil {
+		return true
+	}
+
+	var newPos Coord
+
+	if obj.WandKind() == WandTeleportAway {
+		for {
+			newPos, _ = g.findFloor(true)
+			if newPos != p.Pos {
+				break
+			}
+		}
+	} else {
+		newPos.Y = p.Pos.Y + g.Delta.Y
+		newPos.X = p.Pos.X + g.Delta.X
+	}
+
+	tp.Dest = &p.Pos
+	tp.Flags.Set(Awake)
+	g.relocate(tp, newPos)
+
+	return true
+}
+
+func (g *RogueGame) zapMagicMissile(*Object) bool {
+	p := &g.Player
+
+	g.Items.Sticks[WandMagicMissile].Know = true
+	bolt := newObject()
+	bolt.Kind = KindGold // C set o_type='*': draws a '*' and is not a weapon
+	bolt.HurlDmg = dice("1x4")
+	bolt.HPlus = 100
+	bolt.DPlus = 1
+
+	bolt.Flags = Missile
+	if p.CurWeapon != nil {
+		bolt.Launch = WeaponKind(p.CurWeapon.Which)
+	}
+
+	g.doMotion(bolt, g.Delta.Y, g.Delta.X)
+
+	if tp := g.Level.MonsterAt(bolt.Pos.Y, bolt.Pos.X); tp != nil &&
+		!g.saveThrow(VsMagic, &tp.Stats) {
+		g.hitMonster(bolt.Pos, bolt)
+	} else if g.Options.Terse {
+		g.msg("missle vanishes") //nolint:misspell // C's spelling, kept faithfully
+	} else {
+		g.msg("the missle vanishes with a puff of smoke") //nolint:misspell // C's spelling
+	}
+
+	return true
+}
+
+func (g *RogueGame) zapSpeed(obj *Object) bool {
+	tp := g.zapRayMonster()
+	if tp == nil {
+		return true
+	}
+
+	if obj.WandKind() == WandHasteMonster {
+		hasteTarget(tp)
+	} else {
+		slowTarget(tp)
+	}
+
+	g.Delta.Y = tp.Pos.Y
+	g.Delta.X = tp.Pos.X
+	g.runTo(g.Delta)
+
+	return true
+}
+
+// hasteTarget cancels a slow or applies a haste (the WS_HASTE_M arm of
+// do_zap).
+func hasteTarget(tp *Monster) {
+	if tp.On(Slowed) {
+		tp.Flags.Clear(Slowed)
+	} else {
+		tp.Flags.Set(Hasted)
+	}
+}
+
+// slowTarget cancels a haste or applies a slow (the WS_SLOW_M arm of
+// do_zap).
+func slowTarget(tp *Monster) {
+	if tp.On(Hasted) {
+		tp.Flags.Clear(Hasted)
+	} else {
+		tp.Flags.Set(Slowed)
+	}
+
+	tp.Turn = true
+}
+
+func (g *RogueGame) zapBolt(obj *Object) bool {
+	var name string
+
+	switch obj.WandKind() {
+	case WandLightning:
+		name = "bolt"
+	case WandFire:
+		name = "flame"
+	default:
+		name = "ice"
+	}
+
+	g.fireBolt(g.Player.Pos, &g.Delta, name)
+	g.Items.Sticks[obj.Which].Know = true
+
+	return true
 }
 
 // drain does the drain-hit-points-from-player schtick (sticks.c drain).
@@ -176,22 +293,26 @@ func (g *RogueGame) drain() {
 	// First count how many things we need to spread the hit points among
 	var corp *Room
 	if g.Level.Char(p.Pos.Y, p.Pos.X) == Door {
-		corp = &g.Level.Passages[*g.Level.FlagsAt(p.Pos.Y, p.Pos.X)&FPNum]
+		corp = &g.Level.Passages[*g.Level.FlagsAt(p.Pos.Y, p.Pos.X)&FPassNum]
 	}
-	inpass := p.Room.Flags.Has(IsGone)
+
+	inpass := p.Room.Flags.Has(Gone)
+
 	var drainee []*Monster
+
 	for _, mp := range g.Level.Monsters {
-		if mp.Room == p.Room || mp.Room == corp ||
-			(inpass && g.Level.Char(mp.Pos.Y, mp.Pos.X) == Door &&
-				&g.Level.Passages[*g.Level.FlagsAt(mp.Pos.Y, mp.Pos.X)&FPNum] == p.Room) {
+		if g.drainReaches(mp, corp, inpass) {
 			drainee = append(drainee, mp)
 		}
 	}
+
 	cnt := len(drainee)
 	if cnt == 0 {
 		g.msg("you have a tingling feeling")
+
 		return
 	}
+
 	p.Stats.HP /= 2
 	cnt = p.Stats.HP / cnt
 	// Now zot all of the monsters
@@ -199,11 +320,23 @@ func (g *RogueGame) drain() {
 		if mp.Stats.HP -= cnt; mp.Stats.HP <= 0 {
 			g.killed(mp, g.seeMonst(mp))
 		} else {
-			g.runto(mp.Pos)
+			g.runTo(mp.Pos)
 		}
 	}
 }
 
+// drainReaches reports whether the drain-life wand reaches this monster:
+// the hero's room, the passage behind the door he stands on, or — when
+// he is in a passage — a door of that same passage (the drainee
+// condition of sticks.c drain).
+func (g *RogueGame) drainReaches(mp *Monster, corp *Room, inpass bool) bool {
+	p := &g.Player
+
+	return mp.Room == p.Room || mp.Room == corp ||
+		(inpass && g.Level.Char(mp.Pos.Y, mp.Pos.X) == Door &&
+			&g.Level.Passages[*g.Level.FlagsAt(mp.Pos.Y, mp.Pos.X)&FPassNum] == p.Room)
+}
+
 // fireBolt fires a bolt in a given direction from a specific starting
 // place (sticks.c fire_bolt).
 func (g *RogueGame) fireBolt(start Coord, dir *Coord, name string) {
@@ -211,105 +344,51 @@ func (g *RogueGame) fireBolt(start Coord, dir *Coord, name string) {
 	fromHero := start == p.Pos
 
 	bolt := newObject()
-	bolt.Type = Weapon
-	bolt.Which = Flame
-	bolt.HurlDmg = "6x6"
+	bolt.Kind = KindWeapon
+	bolt.Which = int(WeaponFlame)
+	bolt.HurlDmg = dice("6x6")
 	bolt.HPlus = 100
 	bolt.DPlus = 0
-	g.Items.Weapons[Flame].Name = name
-	var dirch byte
-	switch dir.Y + dir.X {
-	case 0:
-		dirch = '/'
-	case 1, -1:
-		if dir.Y == 0 {
-			dirch = '-'
-		} else {
-			dirch = '|'
-		}
-	case 2, -2:
-		dirch = '\\'
-	}
+	g.Items.Weapons[WeaponFlame].Name = name
+
+	dirch := boltDirChar(*dir)
 	pos := start
 	hitHero := !fromHero
 	used := false
 	changed := false
+
 	var spotpos []Coord
 	for len(spotpos) < BoltLength && !used {
 		pos.Y += dir.Y
 		pos.X += dir.X
 		spotpos = append(spotpos, pos)
+
 		ch := g.Level.VisibleChar(pos.Y, pos.X)
-		bounce := false
-		switch ch {
-		case Door:
-			// this code is necessary if the hero is on a door and he
-			// fires at the wall the door is in, it would otherwise loop
-			// infinitely
-			if p.Pos != pos {
-				bounce = true
-			}
-		case '|', '-', ' ':
-			bounce = true
-		}
-		if bounce {
+		if boltBounces(ch, p.Pos, pos) {
 			if !changed {
 				hitHero = !hitHero
 			}
+
 			changed = false
 			dir.Y = -dir.Y
 			dir.X = -dir.X
 			spotpos = spotpos[:len(spotpos)-1]
+
 			g.msg("the %s bounces", name)
+
 			continue
 		}
+
 		if tp := g.Level.MonsterAt(pos.Y, pos.X); !hitHero && tp != nil {
 			hitHero = true
 			changed = !changed
-			tp.OldCh = g.Level.Char(pos.Y, pos.X)
-			if !g.saveThrow(VsMagic, &tp.Stats) {
-				bolt.Pos = pos
-				used = true
-				if tp.Type == 'D' && name == "flame" {
-					g.addmsg("the flame bounces")
-					if !g.Options.Terse {
-						g.addmsg(" off the dragon")
-					}
-					g.endmsg()
-				} else {
-					g.hitMonster(pos, bolt)
-				}
-			} else if ch != 'M' || tp.Disguise == 'M' {
-				if fromHero {
-					g.runto(pos)
-				}
-				if g.Options.Terse {
-					g.msg("%s misses", name)
-				} else {
-					g.msg("the %s whizzes past %s", name, g.setMname(tp))
-				}
-			}
+			used = g.boltStrikesMonster(tp, bolt, pos, ch, name, fromHero)
 		} else if hitHero && pos == p.Pos {
 			hitHero = false
 			changed = !changed
-			if !g.save(VsMagic) {
-				if p.Stats.HP -= g.roll(6, 6); p.Stats.HP <= 0 {
-					if fromHero {
-						g.death('b')
-					} else {
-						g.death(g.Level.MonsterAt(start.Y, start.X).Type)
-					}
-				}
-				used = true
-				if g.Options.Terse {
-					g.msg("the %s hits", name)
-				} else {
-					g.msg("you are hit by the %s", name)
-				}
-			} else {
-				g.msg("the %s whizzes by you", name)
-			}
+			used = g.boltStrikesHero(start, name, fromHero)
 		}
+
 		g.mvaddch(pos.Y, pos.X, dirch)
 		g.refresh()
 	}
@@ -319,31 +398,132 @@ func (g *RogueGame) fireBolt(start Coord, dir *Coord, name string) {
 	}
 }
 
+// boltDirChar picks the character a traveling bolt is drawn with for its
+// direction (the dirch switch of sticks.c fire_bolt).
+func boltDirChar(dir Coord) byte {
+	switch dir.Y + dir.X {
+	case 0:
+		return '/'
+	case 1, -1:
+		if dir.Y == 0 {
+			return '-'
+		}
+
+		return '|'
+	case 2, -2:
+		return '\\'
+	}
+
+	return 0 // unreachable for the eight legal directions, as in C
+}
+
+// boltBounces reports whether a bolt bounces off this spot: walls, and
+// any door except the one the hero stands on (which would otherwise loop
+// infinitely, per the C comment in fire_bolt).
+func boltBounces(ch byte, heroPos, pos Coord) bool {
+	switch ch {
+	case Door:
+		return heroPos != pos
+	case '|', '-', ' ':
+		return true
+	}
+
+	return false
+}
+
+// boltStrikesMonster resolves a bolt arriving on a monster's square (the
+// monster arm of the fire_bolt loop). It reports whether the bolt was
+// used up.
+func (g *RogueGame) boltStrikesMonster(tp *Monster, bolt *Object, pos Coord, ch byte, name string, fromHero bool) bool {
+	tp.OldCh = g.Level.Char(pos.Y, pos.X)
+	if !g.saveThrow(VsMagic, &tp.Stats) {
+		bolt.Pos = pos
+
+		if tp.Type == 'D' && name == "flame" {
+			g.addmsgf("the flame bounces")
+
+			if !g.Options.Terse {
+				g.addmsgf(" off the dragon")
+			}
+
+			g.endmsg()
+		} else {
+			g.hitMonster(pos, bolt)
+		}
+
+		return true
+	}
+
+	if ch != 'M' || tp.Disguise == 'M' {
+		if fromHero {
+			g.runTo(pos)
+		}
+
+		if g.Options.Terse {
+			g.msg("%s misses", name)
+		} else {
+			g.msg("the %s whizzes past %s", name, g.setMname(tp))
+		}
+	}
+
+	return false
+}
+
+// boltStrikesHero resolves a bolt arriving on the hero (the hero arm of
+// the fire_bolt loop). It reports whether the bolt was used up.
+func (g *RogueGame) boltStrikesHero(start Coord, name string, fromHero bool) bool {
+	p := &g.Player
+	if g.save(VsMagic) {
+		g.msg("the %s whizzes by you", name)
+
+		return false
+	}
+
+	if p.Stats.HP -= g.roll(6, 6); p.Stats.HP <= 0 {
+		if fromHero {
+			g.death('b')
+		} else {
+			g.death(g.Level.MonsterAt(start.Y, start.X).Type)
+		}
+	}
+
+	if g.Options.Terse {
+		g.msg("the %s hits", name)
+	} else {
+		g.msg("you are hit by the %s", name)
+	}
+
+	return true
+}
+
 // fixStick sets up a new wand or staff (sticks.c fix_stick).
 func (g *RogueGame) fixStick(cur *Object) {
-	if g.Items.WandType[cur.Which] == "staff" {
-		cur.Damage = "2x3"
+	if g.Items.WandType[cur.Which] == staffName {
+		cur.Damage = dice("2x3")
 	} else {
-		cur.Damage = "1x1"
+		cur.Damage = dice("1x1")
 	}
-	cur.HurlDmg = "1x1"
 
-	switch cur.Which {
-	case WsLight:
-		cur.SetCharges(g.rnd(10) + 10)
+	cur.HurlDmg = dice("1x1")
+
+	switch cur.WandKind() {
+	case WandLight:
+		cur.Charges = g.rnd(10) + 10
 	default:
-		cur.SetCharges(g.rnd(5) + 3)
+		cur.Charges = g.rnd(5) + 3
 	}
 }
 
 // chargeStr returns the charge-count suffix for an identified stick
 // (sticks.c charge_str).
 func chargeStr(g *RogueGame, obj *Object) string {
-	if !obj.Flags.Has(IsKnow) {
+	if !obj.Flags.Has(Known) {
 		return ""
 	}
+
 	if g.Options.Terse {
-		return fmt.Sprintf(" [%d]", obj.Charges())
+		return fmt.Sprintf(" [%d]", obj.Charges)
 	}
-	return fmt.Sprintf(" [%d charges]", obj.Charges())
+
+	return fmt.Sprintf(" [%d charges]", obj.Charges)
 }

game/tables_test.go

@@ -9,16 +9,20 @@ func TestProbabilitiesSumTo100(t *testing.T) {
 		for _, oi := range info {
 			s += oi.Prob
 		}
+
 		return s
 	}
+
+	data := newGameData()
+
 	tables := map[string][]ObjInfo{
-		"things":  baseThings[:],
-		"potions": basePotInfo[:],
-		"scrolls": baseScrInfo[:],
-		"rings":   baseRingInfo[:],
-		"sticks":  baseWsInfo[:],
-		"weapons": baseWeapInfo[:MaxWeapons], // excludes the flame entry
-		"armor":   baseArmInfo[:],
+		"things":  data.baseThings[:],
+		"potions": data.basePotInfo[:],
+		"scrolls": data.baseScrInfo[:],
+		"rings":   data.baseRingInfo[:],
+		"sticks":  data.baseWsInfo[:],
+		"weapons": data.baseWeapInfo[:NumWeaponTypes], // excludes the flame entry
+		"armor":   data.baseArmInfo[:],
 	}
 	for name, tab := range tables {
 		if s := sum(tab); s != 100 {
@@ -28,12 +32,14 @@ func TestProbabilitiesSumTo100(t *testing.T) {
 }
 
 func TestInitProbsCumulative(t *testing.T) {
-	g := NewGame(Config{Seed: 1})
-	last := g.Items.Potions[MaxPotions-1].Prob
+	g := New(Params{Seed: 1})
+
+	last := g.Items.Potions[NumPotionTypes-1].Prob
 	if last != 100 {
 		t.Errorf("cumulative potion probability ends at %d, want 100", last)
 	}
-	for i := 1; i < MaxPotions; i++ {
+
+	for i := PotionKind(1); i < NumPotionTypes; i++ {
 		if g.Items.Potions[i].Prob < g.Items.Potions[i-1].Prob {
 			t.Errorf("potion probs not nondecreasing at %d", i)
 		}
@@ -41,46 +47,77 @@ func TestInitProbsCumulative(t *testing.T) {
 }
 
 func TestNewGameRandomizesAppearances(t *testing.T) {
-	g := NewGame(Config{Seed: 12345})
-	seen := map[string]bool{}
-	for i, c := range g.Items.PotColors {
-		if c == "" {
-			t.Fatalf("potion %d has no color", i)
-		}
-		if seen[c] {
-			t.Errorf("potion color %q assigned twice", c)
-		}
-		seen[c] = true
-	}
-	for i, n := range g.Items.ScrNames {
-		if n == "" {
-			t.Fatalf("scroll %d has no name", i)
-		}
-		if len(n) > MaxNameLen+1 {
-			t.Errorf("scroll name %q longer than C buffer allows", n)
-		}
-	}
-	for i := range g.Items.WandType {
-		if g.Items.WandType[i] != "wand" && g.Items.WandType[i] != "staff" {
-			t.Errorf("stick %d has type %q", i, g.Items.WandType[i])
-		}
-		if g.Items.WandMade[i] == "" {
-			t.Errorf("stick %d has no material", i)
-		}
-	}
+	g := New(Params{Seed: 12345})
+
+	checkPotionColors(t, g)
+	checkScrollNames(t, g)
+	checkWandMaterials(t, g)
 
 	// Determinism: same seed, same appearances.
-	h := NewGame(Config{Seed: 12345})
+	h := New(Params{Seed: 12345})
 	if h.Items != g.Items {
 		t.Error("two games with the same seed produced different item lore")
 	}
 }
 
+// checkPotionColors verifies every potion has a distinct color.
+func checkPotionColors(t *testing.T, g *RogueGame) {
+	t.Helper()
+
+	seen := map[string]bool{}
+
+	for i, c := range g.Items.PotColors {
+		if c == "" {
+			t.Fatalf("potion %d has no color", i)
+		}
+
+		if seen[c] {
+			t.Errorf("potion color %q assigned twice", c)
+		}
+
+		seen[c] = true
+	}
+}
+
+// checkScrollNames verifies every scroll has a name within the C buffer
+// limit.
+func checkScrollNames(t *testing.T, g *RogueGame) {
+	t.Helper()
+
+	for i, n := range g.Items.ScrNames {
+		if n == "" {
+			t.Fatalf("scroll %d has no name", i)
+		}
+
+		if len(n) > MaxNameLen+1 {
+			t.Errorf("scroll name %q longer than C buffer allows", n)
+		}
+	}
+}
+
+// checkWandMaterials verifies every stick has a wand/staff type and a
+// material.
+func checkWandMaterials(t *testing.T, g *RogueGame) {
+	t.Helper()
+
+	for i := range g.Items.WandType {
+		if g.Items.WandType[i] != wandName && g.Items.WandType[i] != staffName {
+			t.Errorf("stick %d has type %q", i, g.Items.WandType[i])
+		}
+
+		if g.Items.WandMade[i] == "" {
+			t.Errorf("stick %d has no material", i)
+		}
+	}
+}
+
 func TestMonsterTable(t *testing.T) {
-	if monsterTable[0].Name != "aquator" || monsterTable[25].Name != "zombie" {
+	data := newGameData()
+	if data.monsterTable[0].Name != "aquator" || data.monsterTable[25].Name != "zombie" {
 		t.Error("monster table order broken")
 	}
-	if monsterTable['D'-'A'].Name != "dragon" {
+
+	if data.monsterTable['D'-'A'].Name != "dragon" {
 		t.Error("letter indexing broken")
 	}
 }

game/term_test.go

@@ -11,15 +11,20 @@ type testTerm struct {
 
 func (t *testTerm) Render(*Window) {}
 
+func (t *testTerm) Fini() {}
+
 func (t *testTerm) ReadChar() byte {
 	if t.pos < len(t.input) {
 		c := t.input[t.pos]
 		t.pos++
+
 		return c
 	}
+
 	t.tick++
 	if t.tick%2 == 0 {
 		return '\n'
 	}
+
 	return ' '
 }

game/testdata/README.md

@@ -0,0 +1,27 @@
+# Seed-compatibility golden
+
+`item_tables.golden` is the per-seed item appearance tables (potion colors,
+scroll names, ring stones, wand/staff materials) captured from the **C
+reference** on the `modern-rogue` branch, for the seeds in the `seeds` list in
+`TestSeedCompatItemTables`. That test regenerates the same tables from the Go
+port and checks they match byte for byte — proving the LCG and its consumption
+order through the whole init sequence (`init_probs` → `init_player` →
+`init_names` → `init_colors` → `init_stones` → `init_materials`) agree with C.
+
+## Regenerating the golden
+
+`c_seedcompat.patch` adds a `DUMP` mode to the C `main.c`: with `DUMP` set it
+forces the RNG seed from `SEED`, runs the item-table init in the normal order,
+prints the tables, and exits before `initscr` (so no terminal is needed).
+
+```sh
+# from a checkout of the C reference (modern-rogue branch):
+git archive modern-rogue | tar -x -C /tmp/rogue-c
+cd /tmp/rogue-c
+patch -p1 < .../game/testdata/c_seedcompat.patch
+./configure && make
+for s in 1 42 12345 99999; do DUMP=1 SEED=$s ./rogue; done \
+    > .../game/testdata/item_tables.golden
+```
+
+The seed list must match the `seeds` slice in `TestSeedCompatItemTables`.

game/testdata/c_seedcompat.patch

@@ -0,0 +1,37 @@
+--- a/main.c	2026-07-24 03:02:38
++++ b/main.c	2026-07-24 02:48:31
+@@ -63,6 +63,34 @@
+ #endif
+ 	dnum = lowtime + md_getpid();
+     seed = dnum;
++
++    /* SEEDCOMPAT: dump the per-game item appearance tables for a fixed
++     * seed and exit, without initscr. The init sequence and everything
++     * it consumes from rnd() mirror the normal startup (main.c), so the
++     * tables are exactly what a real game with SEED would show. */
++    if (getenv("DUMP") != NULL)
++    {
++	int di;
++	char *sv = getenv("SEED");
++	if (sv != NULL)
++	    seed = atoi(sv);
++	printf("SEED %d\n", seed);
++	init_probs();
++	init_player();
++	init_names();
++	init_colors();
++	init_stones();
++	init_materials();
++	printf("POTIONS\n");
++	for (di = 0; di < MAXPOTIONS; di++) printf("%s\n", p_colors[di]);
++	printf("SCROLLS\n");
++	for (di = 0; di < MAXSCROLLS; di++) printf("%s\n", s_names[di]);
++	printf("RINGS\n");
++	for (di = 0; di < MAXRINGS; di++) printf("%s\n", r_stones[di]);
++	printf("STICKS\n");
++	for (di = 0; di < MAXSTICKS; di++) printf("%s %s\n", ws_type[di], ws_made[di]);
++	exit(0);
++    }
+ 
+     open_score();
+ 

game/testdata/item_tables.golden

@@ -0,0 +1,260 @@
+SEED 1
+POTIONS
+tangerine
+white
+ecru
+gold
+amber
+violet
+vermilion
+pink
+aquamarine
+plaid
+clear
+orange
+cyan
+tan
+SCROLLS
+miwhon garsnanih
+xomimi roke eshwedshu
+potwexrol ipbjorod turs evsnelg
+bekornan oxyfatox
+iv wexpo wun
+ha sefnelgtue whon pay
+alari wedit
+zantmon umzonski umwhonjo yot
+bluoxun rokkho yottrol sta
+vomarg microgcomp iteulkshu mung
+jo urokeep yuskiun
+ox xozantaks klisstaevs ag
+ipnih bek
+shu ami erk
+nejti zim
+iprol mic ishoxyvom fagan
+reacreti oodrol
+bytsri solsa tabu fri
+RINGS
+agate
+zircon
+jade
+tiger eye
+onyx
+germanium
+lapis lazuli
+emerald
+taaffeite
+kryptonite
+garnet
+ruby
+turquoise
+pearl
+STICKS
+wand steel
+wand platinum
+staff redwood
+staff pine
+wand silicon
+staff spruce
+staff pecan
+wand bone
+staff maple
+wand zinc
+wand iron
+wand pewter
+wand electrum
+staff dogwood
+SEED 42
+POTIONS
+blue
+green
+grey
+amber
+violet
+gold
+pink
+tan
+purple
+yellow
+plaid
+magenta
+turquoise
+cyan
+SCROLLS
+bek itod oxytaod oxy
+tarhovzant cre sname oxroy
+plemik ganod hyd wergerkpot
+hyd sol um bekzok
+esh eep ganmung
+anera ishsa ingala mon
+alasniklech viv
+yunejorn garro con nej
+dotrolther gopum eltitrol trolmonsri
+nes alazum
+itegopmung ti
+ere haeta wergla
+nejerecre poipi iprea
+ha falechrhov
+monskiwex sabitla frido
+rhovmar sno
+mar bekurzant satbuzum
+somon sri
+RINGS
+carnelian
+onyx
+jade
+granite
+stibotantalite
+kryptonite
+lapis lazuli
+germanium
+garnet
+tiger eye
+opal
+topaz
+agate
+peridot
+STICKS
+staff birch
+staff ebony
+staff redwood
+wand gold
+wand copper
+wand aluminum
+wand titanium
+wand mercury
+staff cypress
+staff bamboo
+staff dogwood
+wand silicon
+staff zebrawood
+wand beryllium
+SEED 12345
+POTIONS
+purple
+black
+grey
+brown
+plaid
+violet
+vermilion
+ecru
+orange
+turquoise
+tan
+magenta
+silver
+gold
+SCROLLS
+readalf shuplu ivnin
+plelaiv solel skibyt monha
+xo wun
+wedyfri o ewhonxo favompay
+eep zantreanelg
+plu buxo
+un zontabdan
+bie snik
+ulkitzant bluri
+apporg ash posnevly dennepwex
+u urval rol
+arzepotsno snovly pay snoropay
+pottox erewed faoxro
+ther sun ulkipo mik
+argzebfri elgrekli tuenepzon sehturssef
+isheep blumur
+wedash yuzimsun
+plupofri ski rejo fa
+RINGS
+onyx
+tiger eye
+alexandrite
+turquoise
+pearl
+emerald
+germanium
+sapphire
+zircon
+ruby
+granite
+stibotantalite
+opal
+diamond
+STICKS
+wand silicon
+staff ironwood
+staff holly
+wand gold
+staff mahogany
+wand iron
+wand brass
+wand pewter
+staff hemlock
+staff cherry
+staff elm
+wand mercury
+staff banyan
+staff dogwood
+SEED 99999
+POTIONS
+aquamarine
+plaid
+gold
+black
+vermilion
+red
+cyan
+tan
+orange
+violet
+brown
+clear
+silver
+green
+SCROLLS
+zant jocompan vomervly
+mur shusat prok
+prokmurklis oxysriklis
+ingcre prokbu whonengarg kli
+kli bot
+rokcoswerg ipsolsan klisvlypay
+glen yot whontox
+lechme markho fazim
+dalfsunbie micjosef cre comp
+vlyfumi bjorzantbot werg
+po argfidcos klipones
+ashtemarg ycrezim dalfiv whon
+turs unmisa zimpo therdo
+miccompuni uni neswex sef
+odwexing elwergmur mung
+itcon rhov nejmic lech
+garturs engseh ganish
+oodta whonorgsno monabmik vomyeng
+RINGS
+obsidian
+moonstone
+jade
+carnelian
+tiger eye
+taaffeite
+turquoise
+stibotantalite
+agate
+ruby
+onyx
+topaz
+germanium
+granite
+STICKS
+wand titanium
+wand brass
+wand silicon
+staff zebrawood
+wand mercury
+staff dogwood
+wand pewter
+staff cinnibar
+staff kukui wood
+staff banyan
+wand magnesium
+wand gold
+staff maple
+wand nickel

game/things.go

@@ -9,105 +9,163 @@ import (
 
 // invName returns the name of something as it would appear in an inventory
 // (things.c inv_name).
-func (g *RogueGame) invName(obj *Object, drop bool) string {
+func (g *RogueGame) inventoryName(obj *Object, drop bool) string {
 	var pb strings.Builder
+
 	which := obj.Which
 	it := &g.Items
-	switch obj.Type {
-	case Potion:
-		g.nameit(&pb, obj, "potion", it.PotColors[which], &it.Potions[which], nullstr)
-	case Ring:
-		g.nameit(&pb, obj, "ring", it.RingStones[which], &it.Rings[which], ringNum)
-	case Stick:
+
+	switch obj.Kind {
+	case KindPotion:
+		g.nameit(&pb, obj, potionName, it.PotColors[which], &it.Potions[which], nullstr)
+	case KindRing:
+		g.nameit(&pb, obj, ringName, it.RingStones[which], &it.Rings[which], ringNum)
+	case KindWand:
 		g.nameit(&pb, obj, it.WandType[which], it.WandMade[which], &it.Sticks[which], chargeStr)
-	case Scroll:
-		if obj.Count == 1 {
-			pb.WriteString("A scroll ")
-		} else {
-			fmt.Fprintf(&pb, "%d scrolls ", obj.Count)
-		}
-		op := &it.Scrolls[which]
-		if op.Know {
-			fmt.Fprintf(&pb, "of %s", op.Name)
-		} else if op.Guess != "" {
-			fmt.Fprintf(&pb, "called %s", op.Guess)
-		} else {
-			fmt.Fprintf(&pb, "titled '%s'", it.ScrNames[which])
-		}
-	case Food:
-		if which == 1 {
-			if obj.Count == 1 {
-				fmt.Fprintf(&pb, "A%s %s", vowelstr(g.Fruit), g.Fruit)
-			} else {
-				fmt.Fprintf(&pb, "%d %ss", obj.Count, g.Fruit)
-			}
-		} else {
-			if obj.Count == 1 {
-				pb.WriteString("Some food")
-			} else {
-				fmt.Fprintf(&pb, "%d rations of food", obj.Count)
-			}
-		}
-	case Weapon:
-		sp := it.Weapons[which].Name
-		if obj.Count > 1 {
-			fmt.Fprintf(&pb, "%d ", obj.Count)
-		} else {
-			fmt.Fprintf(&pb, "A%s ", vowelstr(sp))
-		}
-		if obj.Flags.Has(IsKnow) {
-			fmt.Fprintf(&pb, "%s %s", num(obj.HPlus, obj.DPlus, Weapon), sp)
-		} else {
-			pb.WriteString(sp)
-		}
-		if obj.Count > 1 {
-			pb.WriteString("s")
-		}
-		if obj.Label != "" {
-			fmt.Fprintf(&pb, " called %s", obj.Label)
-		}
-	case Armor:
-		sp := it.Armors[which].Name
-		if obj.Flags.Has(IsKnow) {
-			fmt.Fprintf(&pb, "%s %s [", num(aClass[which]-obj.Arm, 0, Armor), sp)
-			if !g.Options.Terse {
-				pb.WriteString("protection ")
-			}
-			fmt.Fprintf(&pb, "%d]", 10-obj.Arm)
-		} else {
-			pb.WriteString(sp)
-		}
-		if obj.Label != "" {
-			fmt.Fprintf(&pb, " called %s", obj.Label)
-		}
-	case Amulet:
+	case KindScroll:
+		g.nameScroll(&pb, obj)
+	case KindFood:
+		g.nameFood(&pb, obj)
+	case KindWeapon:
+		g.nameWeapon(&pb, obj)
+	case KindArmor:
+		g.nameArmor(&pb, obj)
+	case KindAmulet:
 		pb.WriteString("The Amulet of Yendor")
-	case Gold:
-		fmt.Fprintf(&pb, "%d Gold pieces", obj.GoldVal())
+	case KindGold:
+		fmt.Fprintf(&pb, "%d Gold pieces", obj.GoldValue)
 	}
 
-	out := pb.String()
-	if g.InvDescribe {
-		p := &g.Player
-		if obj == p.CurArmor {
-			out += " (being worn)"
-		}
-		if obj == p.CurWeapon {
-			out += " (weapon in hand)"
-		}
-		if obj == p.CurRing[Left] {
-			out += " (on left hand)"
-		} else if obj == p.CurRing[Right] {
-			out += " (on right hand)"
-		}
+	return fixNameCase(g.describeWorn(obj, pb.String()), drop)
+}
+
+// nameScroll writes a scroll's inventory name (things.c inv_name).
+func (g *RogueGame) nameScroll(pb *strings.Builder, obj *Object) {
+	if obj.Count == 1 {
+		pb.WriteString("A scroll ")
+	} else {
+		fmt.Fprintf(pb, "%d scrolls ", obj.Count)
 	}
-	if out != "" {
-		if drop && isUpper(out[0]) {
-			out = string(toLower(out[0])) + out[1:]
-		} else if !drop && isLower(out[0]) {
-			out = string(toUpper(out[0])) + out[1:]
-		}
+
+	op := &g.Items.Scrolls[obj.Which]
+
+	switch {
+	case op.Know:
+		fmt.Fprintf(pb, "of %s", op.Name)
+	case op.Guess != "":
+		fmt.Fprintf(pb, "called %s", op.Guess)
+	default:
+		fmt.Fprintf(pb, "titled '%s'", g.Items.ScrNames[obj.Which])
 	}
+}
+
+// nameFood writes a food item's inventory name; which 1 is the fruit
+// (things.c inv_name).
+func (g *RogueGame) nameFood(pb *strings.Builder, obj *Object) {
+	if obj.Which == 1 {
+		if obj.Count == 1 {
+			fmt.Fprintf(pb, "A%s %s", vowelstr(g.Fruit), g.Fruit)
+		} else {
+			fmt.Fprintf(pb, "%d %ss", obj.Count, g.Fruit)
+		}
+
+		return
+	}
+
+	if obj.Count == 1 {
+		pb.WriteString("Some food")
+	} else {
+		fmt.Fprintf(pb, "%d rations of food", obj.Count)
+	}
+}
+
+// nameWeapon writes a weapon's inventory name (things.c inv_name).
+func (g *RogueGame) nameWeapon(pb *strings.Builder, obj *Object) {
+	sp := g.Items.Weapons[obj.Which].Name
+
+	if obj.Count > 1 {
+		fmt.Fprintf(pb, "%d ", obj.Count)
+	} else {
+		fmt.Fprintf(pb, "A%s ", vowelstr(sp))
+	}
+
+	if obj.Flags.Has(Known) {
+		fmt.Fprintf(pb, "%s %s", num(obj.HPlus, obj.DPlus, Weapon), sp)
+	} else {
+		pb.WriteString(sp)
+	}
+
+	if obj.Count > 1 {
+		pb.WriteString("s")
+	}
+
+	if obj.Label != "" {
+		fmt.Fprintf(pb, " called %s", obj.Label)
+	}
+}
+
+// nameArmor writes an armor's inventory name (things.c inv_name).
+func (g *RogueGame) nameArmor(pb *strings.Builder, obj *Object) {
+	sp := g.Items.Armors[obj.Which].Name
+	if obj.Flags.Has(Known) {
+		fmt.Fprintf(pb, "%s %s [",
+			num(g.data.aClass[obj.Which]-obj.ArmorClass, 0, Armor), sp)
+
+		if !g.Options.Terse {
+			pb.WriteString("protection ")
+		}
+
+		fmt.Fprintf(pb, "%d]", 10-obj.ArmorClass)
+	} else {
+		pb.WriteString(sp)
+	}
+
+	if obj.Label != "" {
+		fmt.Fprintf(pb, " called %s", obj.Label)
+	}
+}
+
+// describeWorn appends the equipped-status notes to an inventory name
+// (things.c inv_name).
+func (g *RogueGame) describeWorn(obj *Object, out string) string {
+	if !g.InvDescribe {
+		return out
+	}
+
+	p := &g.Player
+	if obj == p.CurArmor {
+		out += " (being worn)"
+	}
+
+	if obj == p.CurWeapon {
+		out += " (weapon in hand)"
+	}
+
+	switch obj {
+	case p.CurRing[Left]:
+		out += " (on left hand)"
+	case p.CurRing[Right]:
+		out += " (on right hand)"
+	}
+
+	return out
+}
+
+// fixNameCase upper- or lowercases the leading letter to suit the
+// sentence it will land in (things.c inv_name).
+func fixNameCase(out string, drop bool) string {
+	if out == "" {
+		return out
+	}
+
+	if drop && isUpper(out[0]) {
+		return string(toLower(out[0])) + out[1:]
+	}
+
+	if !drop && isLower(out[0]) {
+		return string(toUpper(out[0])) + out[1:]
+	}
+
 	return out
 }
 
@@ -115,29 +173,36 @@ func (g *RogueGame) invName(obj *Object, drop bool) string {
 // leavePack/detach vocabulary collision).
 func (g *RogueGame) dropIt() {
 	p := &g.Player
+
 	ch := g.Level.Char(p.Pos.Y, p.Pos.X)
 	if ch != Floor && ch != Passage {
 		g.After = false
 		g.msg("there is something there already")
+
 		return
 	}
-	obj := g.getItem("drop", 0)
-	if obj == nil {
+
+	obj, ok := g.promptPackItem("drop", KindNone)
+	if !ok {
 		return
 	}
+
 	if !g.dropCheck(obj) {
 		return
 	}
-	obj = g.leavePack(obj, true, !IsMult(obj.Type))
+
+	obj = g.leavePack(obj, true, !obj.Kind.MergesInPack())
 	// Link it into the level object list
-	attachObj(&g.Level.Objects, obj)
-	g.Level.SetChar(p.Pos.Y, p.Pos.X, obj.Type)
+	g.Level.AddObject(obj)
+	g.Level.SetChar(p.Pos.Y, p.Pos.X, obj.Kind.Glyph())
 	g.Level.FlagsAt(p.Pos.Y, p.Pos.X).Set(FDropped)
+
 	obj.Pos = p.Pos
-	if obj.Type == Amulet {
+	if obj.Kind == KindAmulet {
 		g.HasAmulet = false
 	}
-	g.msg("dropped %s", g.invName(obj, true))
+
+	g.msg("dropped %s", g.inventoryName(obj, true))
 }
 
 // dropCheck does special checks for dropping or unwielding|unwearing|
@@ -146,43 +211,60 @@ func (g *RogueGame) dropCheck(obj *Object) bool {
 	if obj == nil {
 		return true
 	}
+
 	p := &g.Player
 	if obj != p.CurArmor && obj != p.CurWeapon &&
 		obj != p.CurRing[Left] && obj != p.CurRing[Right] {
 		return true
 	}
-	if obj.Flags.Has(IsCursed) {
+
+	if obj.Flags.Has(Cursed) {
 		g.msg("you can't.  It appears to be cursed")
+
 		return false
 	}
-	if obj == p.CurWeapon {
+
+	switch obj {
+	case p.CurWeapon:
 		p.CurWeapon = nil
-	} else if obj == p.CurArmor {
+	case p.CurArmor:
 		g.wasteTime()
+
 		p.CurArmor = nil
-	} else {
-		hand := Right
-		if obj == p.CurRing[Left] {
-			hand = Left
-		}
-		p.CurRing[hand] = nil
-		switch obj.Which {
-		case RAddStr:
-			g.chgStr(-obj.Arm)
-		case RSeeInvis:
-			g.unsee(0)
-			g.Extinguish(DUnsee)
-		}
+	default:
+		g.dropRing(obj)
 	}
+
 	return true
 }
 
+// dropRing takes a worn ring off with its side effects (things.c
+// dropcheck).
+func (g *RogueGame) dropRing(obj *Object) {
+	p := &g.Player
+
+	hand := Right
+	if obj == p.CurRing[Left] {
+		hand = Left
+	}
+
+	p.CurRing[hand] = nil
+
+	switch obj.RingKind() {
+	case RingAddStrength:
+		g.changeStrength(-obj.Bonus)
+	case RingSeeInvisible:
+		g.unsee(0)
+		g.Extinguish(DUnsee)
+	}
+}
+
 // newThing returns a new random thing for the dungeon (things.c new_thing).
 func (g *RogueGame) newThing() *Object {
 	cur := newObject()
-	cur.Damage = "0x0"
-	cur.HurlDmg = "0x0"
-	cur.Arm = 11
+	cur.Damage = dice("0x0")
+	cur.HurlDmg = dice("0x0")
+	cur.ArmorClass = 11
 	cur.Count = 1
 
 	// Decide what kind of object it will be; if we haven't had food for a
@@ -193,59 +275,88 @@ func (g *RogueGame) newThing() *Object {
 	} else {
 		kind = pickOne(g, g.Items.Things[:])
 	}
+
 	switch kind {
 	case 0:
-		cur.Type = Potion
+		cur.Kind = KindPotion
 		cur.Which = pickOne(g, g.Items.Potions[:])
 	case 1:
-		cur.Type = Scroll
+		cur.Kind = KindScroll
 		cur.Which = pickOne(g, g.Items.Scrolls[:])
 	case 2:
-		cur.Type = Food
-		g.Player.NoFood = 0
-		if g.rnd(10) != 0 {
-			cur.Which = 0
-		} else {
-			cur.Which = 1
-		}
+		g.newFoodThing(cur)
 	case 3:
-		g.initWeapon(cur, pickOne(g, g.Items.Weapons[:MaxWeapons]))
-		if r := g.rnd(100); r < 10 {
-			cur.Flags.Set(IsCursed)
-			cur.HPlus -= g.rnd(3) + 1
-		} else if r < 15 {
-			cur.HPlus += g.rnd(3) + 1
-		}
+		g.newWeaponThing(cur)
 	case 4:
-		cur.Type = Armor
-		cur.Which = pickOne(g, g.Items.Armors[:])
-		cur.Arm = aClass[cur.Which]
-		if r := g.rnd(100); r < 20 {
-			cur.Flags.Set(IsCursed)
-			cur.Arm += g.rnd(3) + 1
-		} else if r < 28 {
-			cur.Arm -= g.rnd(3) + 1
-		}
+		g.newArmorThing(cur)
 	case 5:
-		cur.Type = Ring
-		cur.Which = pickOne(g, g.Items.Rings[:])
-		switch cur.Which {
-		case RAddStr, RProtect, RAddHit, RAddDam:
-			if cur.Arm = g.rnd(3); cur.Arm == 0 {
-				cur.Arm = -1
-				cur.Flags.Set(IsCursed)
-			}
-		case RAggr, RTeleport:
-			cur.Flags.Set(IsCursed)
-		}
+		g.newRingThing(cur)
 	case 6:
-		cur.Type = Stick
+		cur.Kind = KindWand
 		cur.Which = pickOne(g, g.Items.Sticks[:])
 		g.fixStick(cur)
 	}
+
 	return cur
 }
 
+// newFoodThing rolls food, one time in ten the fruit (things.c
+// new_thing).
+func (g *RogueGame) newFoodThing(cur *Object) {
+	cur.Kind = KindFood
+
+	g.Player.NoFood = 0
+	if g.rnd(10) != 0 {
+		cur.Which = 0
+	} else {
+		cur.Which = 1
+	}
+}
+
+// newWeaponThing rolls a weapon, sometimes cursed or blessed (things.c
+// new_thing).
+func (g *RogueGame) newWeaponThing(cur *Object) {
+	g.initWeapon(cur, WeaponKind(pickOne(g, g.Items.Weapons[:NumWeaponTypes])))
+
+	if r := g.rnd(100); r < 10 {
+		cur.Flags.Set(Cursed)
+		cur.HPlus -= g.rnd(3) + 1
+	} else if r < 15 {
+		cur.HPlus += g.rnd(3) + 1
+	}
+}
+
+// newArmorThing rolls armor, sometimes cursed or blessed (things.c
+// new_thing).
+func (g *RogueGame) newArmorThing(cur *Object) {
+	cur.Kind = KindArmor
+	cur.Which = pickOne(g, g.Items.Armors[:])
+
+	cur.ArmorClass = g.data.aClass[cur.Which]
+	if r := g.rnd(100); r < 20 {
+		cur.Flags.Set(Cursed)
+		cur.ArmorClass += g.rnd(3) + 1
+	} else if r < 28 {
+		cur.ArmorClass -= g.rnd(3) + 1
+	}
+}
+
+// newRingThing rolls a ring, cursing the bad ones (things.c new_thing).
+func (g *RogueGame) newRingThing(cur *Object) {
+	cur.Kind = KindRing
+
+	cur.Which = pickOne(g, g.Items.Rings[:])
+	switch cur.RingKind() {
+	case RingAddStrength, RingProtection, RingDexterity, RingIncreaseDamage:
+		if cur.Bonus = g.rnd(3); cur.Bonus == 0 {
+			cur.Bonus = -1
+			cur.Flags.Set(Cursed)
+		}
+	case RingAggravateMonsters, RingTeleportation:
+		cur.Flags.Set(Cursed)
+	}
+}
+
 // pickOne picks an item out of a list of possible objects using their
 // cumulative probabilities (things.c pick_one).
 func pickOne(g *RogueGame, info []ObjInfo) int {
@@ -255,6 +366,7 @@ func pickOne(g *RogueGame, info []ObjInfo) int {
 			return idx
 		}
 	}
+
 	return 0 // bad pick_one: C resets to the start of the table
 }
 
@@ -272,20 +384,27 @@ type invPage struct {
 // (things.c discovered).
 func (g *RogueGame) discovered() {
 	var ch byte
+
 	for {
 		discList := false
+
 		if !g.Options.Terse {
-			g.addmsg("for ")
+			g.addmsgf("for ")
 		}
-		g.addmsg("what type")
+
+		g.addmsgf("what type")
+
 		if !g.Options.Terse {
-			g.addmsg(" of object do you want a list")
+			g.addmsgf(" of object do you want a list")
 		}
+
 		g.msg("? (* for all)")
+
 		ch = g.readchar()
 		switch ch {
 		case Escape:
 			g.msg("")
+
 			return
 		case Potion, Scroll, Ring, Stick, '*':
 			discList = true
@@ -297,10 +416,12 @@ func (g *RogueGame) discovered() {
 					Potion, Scroll, Ring, Stick)
 			}
 		}
+
 		if discList {
 			break
 		}
 	}
+
 	if ch == '*' {
 		g.printDisc(Potion)
 		g.addLine("")
@@ -320,6 +441,7 @@ func (g *RogueGame) discovered() {
 // (things.c print_disc).
 func (g *RogueGame) printDisc(typ byte) {
 	var info []ObjInfo
+
 	switch typ {
 	case Scroll:
 		info = g.Items.Scrolls[:]
@@ -330,18 +452,23 @@ func (g *RogueGame) printDisc(typ byte) {
 	case Stick:
 		info = g.Items.Sticks[:]
 	}
+
 	order := make([]int, len(info))
 	g.setOrder(order)
+
 	obj := Object{Count: 1}
 	numFound := 0
+
 	for i := range info {
 		if info[order[i]].Know || info[order[i]].Guess != "" {
-			obj.Type = typ
+			obj.Kind = objectKindForGlyph(typ)
 			obj.Which = order[i]
-			g.addLine("%s", g.invName(&obj, false))
+			g.addLine("%s", g.inventoryName(&obj, false))
+
 			numFound++
 		}
 	}
+
 	if numFound == 0 {
 		g.addLine("%s", g.nothing(typ))
 	}
@@ -353,6 +480,7 @@ func (g *RogueGame) setOrder(order []int) {
 	for i := range order {
 		order[i] = i
 	}
+
 	for i := len(order); i > 0; i-- {
 		r := g.rnd(i)
 		order[i-1], order[r] = order[r], order[i-1]
@@ -366,8 +494,8 @@ const flushSentinel = "\x00"
 
 func (g *RogueGame) addLine(format string, a ...any) int {
 	pg := &g.invPage
-	prompt := "--Press space to continue--"
 	isFlush := format == flushSentinel
+
 	var line string
 	if !isFlush {
 		line = fmt.Sprintf(format, a...)
@@ -375,64 +503,107 @@ func (g *RogueGame) addLine(format string, a ...any) int {
 
 	if pg.lineCnt == 0 {
 		g.scr.Hw.Clear()
+
 		if g.Options.InvType == InvSlow {
 			g.Msgs.Mpos = 0
 		}
 	}
+
 	if g.Options.InvType == InvSlow {
-		if !isFlush && line != "" {
-			if g.msg("%s", line) == Escape {
-				return Escape
-			}
-		}
-		pg.lineCnt++
-	} else {
-		if !pg.init {
-			pg.maxlen = len(prompt)
-			pg.init = true
-		}
-		if pg.lineCnt >= NumLines-1 || isFlush {
-			if g.Options.InvType == InvOver && isFlush && !pg.newpage {
-				// Overlay the accumulated list in a box at the top right
-				// of the screen, prompt, and restore what was beneath.
-				g.msg("")
-				g.refresh()
-				saved := NewWindow(NumLines, NumCols)
-				saved.CopyFrom(g.scr.Std)
-				lx := NumCols - pg.maxlen - 2
-				for y := 0; y <= pg.lineCnt; y++ {
-					for x := 0; x <= pg.maxlen; x++ {
-						g.scr.Std.MvAddCh(y, lx+x, g.scr.Hw.MvInch(y, x))
-					}
-				}
-				g.scr.Std.MvAddStr(pg.lineCnt, lx, prompt)
-				g.refresh()
-				g.waitFor(' ')
-				g.scr.Std.CopyFrom(saved)
-				g.refresh()
-			} else {
-				g.scr.Hw.MvAddStr(NumLines-1, 0, prompt)
-				g.scr.RefreshWin(g.scr.Hw)
-				g.waitFor(' ')
-				g.scr.Hw.Clear()
-				g.refresh()
-			}
-			pg.newpage = true
-			pg.lineCnt = 0
-			pg.maxlen = len(prompt)
-		}
-		if !isFlush && !(pg.lineCnt == 0 && line == "") {
-			g.scr.Hw.MvAddStr(pg.lineCnt, 0, line)
-			pg.lineCnt++
-			if pg.maxlen < len(line) {
-				pg.maxlen = len(line)
-			}
-			pg.lastLine = line
+		return g.addLineSlow(line, isFlush)
+	}
+
+	g.addLinePaged(line, isFlush)
+
+	return ^Escape
+}
+
+// addLineSlow shows one discovery line as a message (the slow-inventory
+// arm of things.c add_line).
+func (g *RogueGame) addLineSlow(line string, isFlush bool) int {
+	if !isFlush && line != "" {
+		if g.msg("%s", line) == Escape {
+			return Escape
 		}
 	}
+
+	g.invPage.lineCnt++
+
 	return ^Escape
 }
 
+// addLinePaged accumulates discovery lines into the paged window,
+// prompting between full pages (the windowed arm of things.c add_line).
+func (g *RogueGame) addLinePaged(line string, isFlush bool) {
+	pg := &g.invPage
+	prompt := "--Press space to continue--"
+
+	if !pg.init {
+		pg.maxlen = len(prompt)
+		pg.init = true
+	}
+
+	if pg.lineCnt >= NumLines-1 || isFlush {
+		g.addLinePageBreak(prompt, isFlush)
+	}
+
+	if !isFlush && (pg.lineCnt != 0 || line != "") {
+		g.scr.Hw.MvAddStr(pg.lineCnt, 0, line)
+
+		pg.lineCnt++
+		if pg.maxlen < len(line) {
+			pg.maxlen = len(line)
+		}
+
+		pg.lastLine = line
+	}
+}
+
+// addLinePageBreak prompts at a full page and starts a fresh one
+// (things.c add_line).
+func (g *RogueGame) addLinePageBreak(prompt string, isFlush bool) {
+	pg := &g.invPage
+	if g.Options.InvType == InvOver && isFlush && !pg.newpage {
+		g.addLineOverlay(prompt)
+	} else {
+		g.scr.Hw.MvAddStr(NumLines-1, 0, prompt)
+		g.scr.RefreshWin(g.scr.Hw)
+		g.waitFor(' ')
+		g.scr.Hw.Clear()
+		g.refresh()
+	}
+
+	pg.newpage = true
+	pg.lineCnt = 0
+	pg.maxlen = len(prompt)
+}
+
+// addLineOverlay draws the accumulated list in a box at the top right
+// of the screen, prompts, and restores what was beneath (things.c
+// add_line).
+func (g *RogueGame) addLineOverlay(prompt string) {
+	pg := &g.invPage
+
+	g.msg("")
+	g.refresh()
+
+	saved := NewWindow(NumLines, NumCols)
+	saved.CopyFrom(g.scr.Std)
+
+	lx := NumCols - pg.maxlen - 2
+	for y := 0; y <= pg.lineCnt; y++ {
+		for x := 0; x <= pg.maxlen; x++ {
+			g.scr.Std.MvAddCh(y, lx+x, g.scr.Hw.MvInch(y, x))
+		}
+	}
+
+	g.scr.Std.MvAddStr(pg.lineCnt, lx, prompt)
+	g.refresh()
+	g.waitFor(' ')
+	g.scr.Std.CopyFrom(saved)
+	g.refresh()
+}
+
 // flushLine is add_line(NULL): force out the accumulated page.
 func (g *RogueGame) flushLine() int { return g.addLine(flushSentinel) }
 
@@ -447,6 +618,7 @@ func (g *RogueGame) endLine() {
 			g.flushLine()
 		}
 	}
+
 	pg.lineCnt = 0
 	pg.newpage = false
 }
@@ -459,20 +631,24 @@ func (g *RogueGame) nothing(typ byte) string {
 	} else {
 		out = "Haven't discovered anything"
 	}
+
 	if typ != '*' {
 		var tystr string
+
 		switch typ {
 		case Potion:
-			tystr = "potion"
+			tystr = potionName
 		case Scroll:
-			tystr = "scroll"
+			tystr = scrollName
 		case Ring:
-			tystr = "ring"
+			tystr = ringName
 		case Stick:
 			tystr = "stick"
 		}
+
 		out += fmt.Sprintf(" about any %ss", tystr)
 	}
+
 	return out
 }
 
@@ -480,20 +656,22 @@ func (g *RogueGame) nothing(typ byte) string {
 // (things.c nameit).
 func (g *RogueGame) nameit(pb *strings.Builder, obj *Object, typ, which string,
 	op *ObjInfo, prfunc func(*RogueGame, *Object) string) {
-	if op.Know || op.Guess != "" {
+	switch {
+	case op.Know || op.Guess != "":
 		if obj.Count == 1 {
 			fmt.Fprintf(pb, "A %s ", typ)
 		} else {
 			fmt.Fprintf(pb, "%d %ss ", obj.Count, typ)
 		}
+
 		if op.Know {
 			fmt.Fprintf(pb, "of %s%s(%s)", op.Name, prfunc(g, obj), which)
 		} else {
 			fmt.Fprintf(pb, "called %s%s(%s)", op.Guess, prfunc(g, obj), which)
 		}
-	} else if obj.Count == 1 {
+	case obj.Count == 1:
 		fmt.Fprintf(pb, "A%s %s %s", vowelstr(which), which, typ)
-	} else {
+	default:
 		fmt.Fprintf(pb, "%d %s %ss", obj.Count, which, typ)
 	}
 }
@@ -505,13 +683,17 @@ func nullstr(*RogueGame, *Object) string { return "" }
 // pr_list).
 func (g *RogueGame) prList() {
 	if !g.Options.Terse {
-		g.addmsg("for ")
+		g.addmsgf("for ")
 	}
-	g.addmsg("what type")
+
+	g.addmsgf("what type")
+
 	if !g.Options.Terse {
-		g.addmsg(" of object do you want a list")
+		g.addmsgf(" of object do you want a list")
 	}
+
 	g.msg("? ")
+
 	ch := g.readchar()
 	switch ch {
 	case Potion:
@@ -525,7 +707,7 @@ func (g *RogueGame) prList() {
 	case Armor:
 		g.prSpec(g.Items.Armors[:])
 	case Weapon:
-		g.prSpec(g.Items.Weapons[:MaxWeapons])
+		g.prSpec(g.Items.Weapons[:NumWeaponTypes])
 	}
 }
 
@@ -533,14 +715,17 @@ func (g *RogueGame) prList() {
 // (things.c pr_spec).
 func (g *RogueGame) prSpec(info []ObjInfo) {
 	lastprob := 0
+
 	i := byte('0')
 	for idx := range info {
 		if i == '9'+1 {
 			i = 'a'
 		}
+
 		g.addLine("%c: %s (%d%%)", i, info[idx].Name, info[idx].Prob-lastprob)
 		lastprob = info[idx].Prob
 		i++
 	}
+
 	g.endLine()
 }

game/types.go

@@ -62,12 +62,6 @@ const (
 	Stick    byte = '/'
 )
 
-// Pseudo-types for item-selection prompts (rogue.h)
-const (
-	Callable = -1
-	RorS     = -2
-)
-
 // Various constants (rogue.h)
 const (
 	HealTime    = 30
@@ -96,202 +90,253 @@ const (
 	VsMagic        = 3
 )
 
-// Flags for rooms (rogue.h)
+// RoomFlags are the room state bits (rogue.h room flags).
 type RoomFlags int16
 
+// Room state bits (rogue.h ISDARK/ISGONE/ISMAZE).
 const (
-	IsDark RoomFlags = 1 << iota // room is dark
-	IsGone                       // room is gone (a corridor)
-	IsMaze                       // room is a maze
+	Dark RoomFlags = 1 << iota // room is dark
+	Gone                       // room is gone (a corridor)
+	Maze                       // room is a maze
 )
 
-func (f RoomFlags) Has(b RoomFlags) bool { return f&b != 0 }
-func (f *RoomFlags) Set(b RoomFlags)     { *f |= b }
-func (f *RoomFlags) Clear(b RoomFlags)   { *f &^= b }
+// Has reports whether any of the given bits are set.
+func (f *RoomFlags) Has(b RoomFlags) bool { return *f&b != 0 }
 
-// Flags for objects (rogue.h)
+// Set turns the given bits on.
+func (f *RoomFlags) Set(b RoomFlags) { *f |= b }
+
+// Clear turns the given bits off.
+func (f *RoomFlags) Clear(b RoomFlags) { *f &^= b }
+
+// ObjFlags are the object state bits (rogue.h object flags).
 type ObjFlags int32
 
+// Object state bits (rogue.h).
 const (
-	IsCursed   ObjFlags = 1 << iota // object is cursed
-	IsKnow                          // player knows details about the object
-	IsMissl                         // object is a missile type
-	IsMany                          // object comes in groups
-	ObjIsFound                      // object has been seen (ISFOUND shares the bit with creatures)
-	IsProt                          // armor is permanently protected
+	Cursed    ObjFlags = 1 << iota // ISCURSED: object is cursed
+	Known                          // ISKNOW: player knows details about the object
+	Missile                        // ISMISL: object is a missile type
+	Stackable                      // ISMANY: object comes in groups
+	WasFound                       // ISFOUND (objects): object has been seen (ISFOUND shares the bit with creatures)
+	Protected                      // ISPROT: armor is permanently protected
 )
 
-func (f ObjFlags) Has(b ObjFlags) bool { return f&b != 0 }
-func (f *ObjFlags) Set(b ObjFlags)     { *f |= b }
-func (f *ObjFlags) Clear(b ObjFlags)   { *f &^= b }
+// Has reports whether any of the given bits are set.
+func (f *ObjFlags) Has(b ObjFlags) bool { return *f&b != 0 }
 
-// Flags for creatures (rogue.h). The C bit collisions are deliberate and
-// preserved: one name of each pair applies to monsters, the other to the
-// hero, and they never coexist on one creature.
+// Set turns the given bits on.
+func (f *ObjFlags) Set(b ObjFlags) { *f |= b }
+
+// Clear turns the given bits off.
+func (f *ObjFlags) Clear(b ObjFlags) { *f &^= b }
+
+// CreatureFlags are the creature state bits (rogue.h creature flags). The
+// C bit collisions are deliberate and preserved: one name of each pair
+// applies to monsters, the other to the hero, and they never coexist on
+// one creature.
 type CreatureFlags int32
 
+// Creature state bits (rogue.h).
 const (
-	CanHuh   CreatureFlags = 0o000001 // creature can confuse
-	CanSee   CreatureFlags = 0o000002 // creature can see invisible creatures
-	IsBlind  CreatureFlags = 0o000004 // creature is blind
-	IsCanc   CreatureFlags = 0o000010 // creature has special qualities cancelled
-	IsLevit  CreatureFlags = 0o000010 // hero is levitating
-	IsFound  CreatureFlags = 0o000020 // creature has been seen
-	IsGreed  CreatureFlags = 0o000040 // creature runs to protect gold
-	IsHaste  CreatureFlags = 0o000100 // creature has been hastened
-	IsTarget CreatureFlags = 0o000200 // creature is the target of an 'f' command
-	IsHeld   CreatureFlags = 0o000400 // creature has been held
-	IsHuh    CreatureFlags = 0o001000 // creature is confused
-	IsInvis  CreatureFlags = 0o002000 // creature is invisible
-	IsMean   CreatureFlags = 0o004000 // creature can wake when player enters room
-	IsHalu   CreatureFlags = 0o004000 // hero is on acid trip
-	IsRegen  CreatureFlags = 0o010000 // creature can regenerate
-	IsRun    CreatureFlags = 0o020000 // creature is running at the player
-	SeeMonst CreatureFlags = 0o040000 // hero can detect unseen monsters
-	IsFly    CreatureFlags = 0o040000 // creature can fly
-	IsSlow   CreatureFlags = 0o100000 // creature has been slowed
+	CanConfuse      CreatureFlags = 0o000001 // CANHUH: creature can confuse
+	CanSeeInvisible CreatureFlags = 0o000002 // CANSEE: creature can see invisible creatures
+	Blind           CreatureFlags = 0o000004 // ISBLIND: creature is blind
+	Cancelled       CreatureFlags = 0o000010 // ISCANC: creature has special qualities cancelled
+	Levitating      CreatureFlags = 0o000010 // ISLEVIT: hero is levitating
+	Found           CreatureFlags = 0o000020 // ISFOUND: creature has been seen
+	Greedy          CreatureFlags = 0o000040 // ISGREED: creature runs to protect gold
+	Hasted          CreatureFlags = 0o000100 // ISHASTE: creature has been hastened
+	Targeted        CreatureFlags = 0o000200 // ISTARGET: creature is the target of an 'f' command
+	Held            CreatureFlags = 0o000400 // ISHELD: creature has been held
+	Confused        CreatureFlags = 0o001000 // ISHUH: creature is confused
+	Invisible       CreatureFlags = 0o002000 // ISINVIS: creature is invisible
+	Mean            CreatureFlags = 0o004000 // ISMEAN: creature can wake when player enters room
+	Hallucinating   CreatureFlags = 0o004000 // ISHALU: hero is on acid trip
+	Regenerates     CreatureFlags = 0o010000 // ISREGEN: creature can regenerate
+	Awake           CreatureFlags = 0o020000 // ISRUN: creature is running at the player
+	SenseMonsters   CreatureFlags = 0o040000 // SEEMONST: hero can detect unseen monsters
+	Flying          CreatureFlags = 0o040000 // ISFLY: creature can fly
+	Slowed          CreatureFlags = 0o100000 // ISSLOW: creature has been slowed
 )
 
-func (f CreatureFlags) Has(b CreatureFlags) bool { return f&b != 0 }
-func (f *CreatureFlags) Set(b CreatureFlags)     { *f |= b }
-func (f *CreatureFlags) Clear(b CreatureFlags)   { *f &^= b }
+// Has reports whether any of the given bits are set.
+func (f *CreatureFlags) Has(b CreatureFlags) bool { return *f&b != 0 }
 
-// Flags for the level map (rogue.h)
+// Set turns the given bits on.
+func (f *CreatureFlags) Set(b CreatureFlags) { *f |= b }
+
+// Clear turns the given bits off.
+func (f *CreatureFlags) Clear(b CreatureFlags) { *f &^= b }
+
+// PlaceFlags are the per-map-cell bits (rogue.h level map flags). The low
+// bits double as the passage number (FPassNum) or trap kind (FTrapMask).
 type PlaceFlags uint8
 
+// Map cell bits (rogue.h).
 const (
-	FPass    PlaceFlags = 0x80 // is a passageway
-	FSeen    PlaceFlags = 0x40 // have seen this spot before
-	FDropped PlaceFlags = 0x20 // object was dropped here
-	FLocked  PlaceFlags = 0x20 // door is locked
-	FReal    PlaceFlags = 0x10 // what you see is what you get
-	FPNum    PlaceFlags = 0x0f // passage number mask
-	FTMask   PlaceFlags = 0x07 // trap number mask
+	FPassage  PlaceFlags = 0x80 // F_PASS: is a passageway
+	FSeen     PlaceFlags = 0x40 // have seen this spot before
+	FDropped  PlaceFlags = 0x20 // object was dropped here
+	FLocked   PlaceFlags = 0x20 // door is locked
+	FReal     PlaceFlags = 0x10 // what you see is what you get
+	FPassNum  PlaceFlags = 0x0f // F_PNUM: passage number mask
+	FTrapMask PlaceFlags = 0x07 // F_TMASK: trap number mask
 )
 
-func (f PlaceFlags) Has(b PlaceFlags) bool { return f&b != 0 }
-func (f *PlaceFlags) Set(b PlaceFlags)     { *f |= b }
-func (f *PlaceFlags) Clear(b PlaceFlags)   { *f &^= b }
+// Has reports whether any of the given bits are set.
+func (f *PlaceFlags) Has(b PlaceFlags) bool { return *f&b != 0 }
 
-// Trap types (rogue.h)
+// Set turns the given bits on.
+func (f *PlaceFlags) Set(b PlaceFlags) { *f |= b }
+
+// Clear turns the given bits off.
+func (f *PlaceFlags) Clear(b PlaceFlags) { *f &^= b }
+
+// TrapKind identifies a trap (rogue.h trap types). The kind is stored in
+// the low bits of a map cell's PlaceFlags (FTrapMask).
+type TrapKind int
+
+// Trap kinds (rogue.h T_* constants).
 const (
-	TDoor  = 0
-	TArrow = 1
-	TSleep = 2
-	TBear  = 3
-	TTelep = 4
-	TDart  = 5
-	TRust  = 6
-	TMyst  = 7
-	NTraps = 8
+	TrapDoor     TrapKind = 0
+	TrapArrow    TrapKind = 1
+	TrapSleep    TrapKind = 2
+	TrapBear     TrapKind = 3
+	TrapTeleport TrapKind = 4
+	TrapDart     TrapKind = 5
+	TrapRust     TrapKind = 6
+	TrapMystery  TrapKind = 7
+	NumTrapTypes          = 8
 )
 
-// Potion types (rogue.h)
+// PotionKind identifies a potion (rogue.h potion types).
+type PotionKind int
+
+// Potion kinds (rogue.h)
 const (
-	PConfuse = iota
-	PLSD
-	PPoison
-	PStrength
-	PSeeInvis
-	PHealing
-	PMFind
-	PTFind
-	PRaise
-	PXHeal
-	PHaste
-	PRestore
-	PBlind
-	PLevit
-	MaxPotions
+	PotionConfusion PotionKind = iota
+	PotionLSD
+	PotionPoison
+	PotionGainStrength
+	PotionSeeInvisible
+	PotionHealing
+	PotionDetectMonsters
+	PotionDetectMagic
+	PotionRaiseLevel
+	PotionExtraHealing
+	PotionHaste
+	PotionRestoreStrength
+	PotionBlindness
+	PotionLevitation
+	NumPotionTypes
 )
 
-// Scroll types (rogue.h)
+// ScrollKind identifies a scroll (rogue.h scroll types).
+type ScrollKind int
+
+// Scroll kinds (rogue.h)
 const (
-	SConfuse = iota
-	SMap
-	SHold
-	SSleep
-	SArmor
-	SIDPotion
-	SIDScroll
-	SIDWeapon
-	SIDArmor
-	SIDRorS
-	SScare
-	SFDet
-	STelep
-	SEnch
-	SCreate
-	SRemove
-	SAggr
-	SProtect
-	MaxScrolls
+	ScrollMonsterConfusion ScrollKind = iota
+	ScrollMagicMapping
+	ScrollHoldMonster
+	ScrollSleep
+	ScrollEnchantArmor
+	ScrollIdentifyPotion
+	ScrollIdentifyScroll
+	ScrollIdentifyWeapon
+	ScrollIdentifyArmor
+	ScrollIdentifyRingOrStick
+	ScrollScareMonster
+	ScrollFoodDetection
+	ScrollTeleportation
+	ScrollEnchantWeapon
+	ScrollCreateMonster
+	ScrollRemoveCurse
+	ScrollAggravateMonsters
+	ScrollProtectArmor
+	NumScrollTypes
 )
 
-// Weapon types (rogue.h)
+// WeaponKind identifies a weapon (rogue.h weapon types).
+type WeaponKind int
+
+// Weapon kinds (rogue.h)
 const (
-	Mace = iota
-	Sword
-	Bow
-	Arrow
-	Dagger
-	TwoSword
-	Dart
-	Shiraken
-	Spear
-	Flame      // fake entry for dragon breath (ick)
-	MaxWeapons = Flame
+	WeaponMace WeaponKind = iota
+	WeaponLongSword
+	WeaponBow
+	WeaponArrow
+	WeaponDagger
+	WeaponTwoHandedSword
+	WeaponDart
+	WeaponShuriken
+	WeaponSpear
+	WeaponFlame // fake entry for dragon breath (ick)
 )
 
-// Armor types (rogue.h)
+// NumWeaponTypes counts the real weapons; the flame pseudo-weapon sits
+// just past them in the tables (C's MAXWEAPONS == FLAME).
+const NumWeaponTypes = WeaponFlame
+
+// ArmorKind identifies a suit of armor (rogue.h armor types).
+type ArmorKind int
+
+// Armor kinds (rogue.h)
 const (
-	Leather = iota
-	RingMail
-	StuddedLeather
-	ScaleMail
-	ChainMail
-	SplintMail
-	BandedMail
-	PlateMail
-	MaxArmors
+	ArmorLeather ArmorKind = iota
+	ArmorRingMail
+	ArmorStuddedLeather
+	ArmorScaleMail
+	ArmorChainMail
+	ArmorSplintMail
+	ArmorBandedMail
+	ArmorPlateMail
+	NumArmorTypes
 )
 
-// Ring types (rogue.h)
+// RingKind identifies a ring (rogue.h ring types).
+type RingKind int
+
+// Ring kinds (rogue.h)
 const (
-	RProtect = iota
-	RAddStr
-	RSustStr
-	RSearch
-	RSeeInvis
-	RNop
-	RAggr
-	RAddHit
-	RAddDam
-	RRegen
-	RDigest
-	RTeleport
-	RStealth
-	RSustArm
-	MaxRings
+	RingProtection RingKind = iota
+	RingAddStrength
+	RingSustainStrength
+	RingSearching
+	RingSeeInvisible
+	RingAdornment
+	RingAggravateMonsters
+	RingDexterity
+	RingIncreaseDamage
+	RingRegeneration
+	RingSlowDigestion
+	RingTeleportation
+	RingStealth
+	RingMaintainArmor
+	NumRingTypes
 )
 
-// Rod/Wand/Staff types (rogue.h)
+// WandKind identifies a wand or staff (rogue.h rod/wand/staff types).
+type WandKind int
+
+// Wand kinds (rogue.h)
 const (
-	WsLight = iota
-	WsInvis
-	WsElect
-	WsFire
-	WsCold
-	WsPolymorph
-	WsMissile
-	WsHasteM
-	WsSlowM
-	WsDrain
-	WsNop
-	WsTelAway
-	WsTelTo
-	WsCancel
-	MaxSticks
+	WandLight WandKind = iota
+	WandInvisibility
+	WandLightning
+	WandFire
+	WandCold
+	WandPolymorph
+	WandMagicMissile
+	WandHasteMonster
+	WandSlowMonster
+	WandDrainLife
+	WandNothing
+	WandTeleportAway
+	WandTeleportTo
+	WandCancellation
+	NumWandTypes
 )
 
 // Coord is a position on the level (rogue.h coord). A value type: the C
@@ -302,13 +347,13 @@ type Coord struct {
 
 // Stats describes a fighting being (rogue.h struct stats).
 type Stats struct {
-	Str   int    // strength (s_str; 3..31)
-	Exp   int    // experience
-	Lvl   int    // level of mastery
-	Arm   int    // armor class
-	HP    int    // hit points (s_hpt)
-	Dmg   string // damage dice, e.g. "1x4/1x2"
-	MaxHP int
+	Str        int      // strength (s_str; 3..31)
+	Exp        int      // experience
+	Lvl        int      // level of mastery
+	ArmorClass int      // armor class (s_arm)
+	HP         int      // hit points (s_hpt)
+	Dmg        DiceSpec // damage dice, e.g. "1x4/1x2"
+	MaxHP      int
 }
 
 // Room describes a room or passage network (rogue.h struct room).
@@ -349,13 +394,11 @@ type Stone struct {
 // CTRL maps a letter to its control character, as the C CTRL() macro.
 func CTRL(c byte) byte { return c & 0o37 }
 
-// IsMult reports whether an object type stacks in the pack (rogue.h ISMULT).
-func IsMult(typ byte) bool { return typ == Potion || typ == Scroll || typ == Food }
-
 // distance returns the squared distance between two points (chase.c dist).
 func distance(y1, x1, y2, x2 int) int {
 	dx := x2 - x1
 	dy := y2 - y1
+
 	return dx*dx + dy*dy
 }
 
@@ -370,5 +413,6 @@ func sign(nm int) int {
 	case nm > 0:
 		return 1
 	}
+
 	return 0
 }

game/weapons.go

@@ -4,18 +4,20 @@ import "fmt"
 
 // weapons.c — functions for dealing with problems brought about by weapons.
 
-const noWeapon = -1
+const noWeapon WeaponKind = -1
 
 // missile fires a missile in a given direction (weapons.c missile).
 func (g *RogueGame) missile(ydelta, xdelta int) {
 	// Get which thing we are hurling
-	obj := g.getItem("throw", int(Weapon))
-	if obj == nil {
+	obj, ok := g.promptPackItem("throw", KindWeapon)
+	if !ok {
 		return
 	}
+
 	if !g.dropCheck(obj) || g.isCurrent(obj) {
 		return
 	}
+
 	obj = g.leavePack(obj, true, false)
 	g.doMotion(obj, ydelta, xdelta)
 	// AHA! Here it has hit something.  If it is a wall or a door, or if
@@ -33,51 +35,64 @@ func (g *RogueGame) doMotion(obj *Object, ydelta, xdelta int) {
 	// Come fly with us ...
 	obj.Pos = p.Pos
 	for {
-		// Erase the old one
-		if obj.Pos != p.Pos && g.cansee(obj.Pos.Y, obj.Pos.X) && !g.Options.Terse {
-			ch := g.Level.Char(obj.Pos.Y, obj.Pos.X)
-			if ch == Floor && !g.showFloor() {
-				ch = ' '
-			}
-			g.mvaddch(obj.Pos.Y, obj.Pos.X, ch)
-		}
+		g.eraseFlight(obj, p.Pos)
 		// Get the new position
 		obj.Pos.Y += ydelta
 		obj.Pos.X += xdelta
+
 		ch := g.Level.VisibleChar(obj.Pos.Y, obj.Pos.X)
-		if stepOk(ch) && ch != Door {
-			// It hasn't hit anything yet, so display it if it's alright.
-			if g.cansee(obj.Pos.Y, obj.Pos.X) && !g.Options.Terse {
-				g.mvaddch(obj.Pos.Y, obj.Pos.X, obj.Type)
-				g.refresh()
-			}
-			continue
+		if !stepOk(ch) || ch == Door {
+			break
+		}
+		// It hasn't hit anything yet, so display it if it's alright.
+		if g.canSee(obj.Pos.Y, obj.Pos.X) && !g.Options.Terse {
+			g.mvaddch(obj.Pos.Y, obj.Pos.X, obj.Kind.Glyph())
+			g.refresh()
 		}
-		break
 	}
 }
 
+// eraseFlight erases a flying object from its current square, unless it
+// still sits on the hero (the erase step of weapons.c do_motion).
+func (g *RogueGame) eraseFlight(obj *Object, heroPos Coord) {
+	if obj.Pos == heroPos || !g.canSee(obj.Pos.Y, obj.Pos.X) || g.Options.Terse {
+		return
+	}
+
+	ch := g.Level.Char(obj.Pos.Y, obj.Pos.X)
+	if ch == Floor && !g.showFloor() {
+		ch = ' '
+	}
+
+	g.mvaddch(obj.Pos.Y, obj.Pos.X, ch)
+}
+
 // fall drops an item someplace around here (weapons.c fall).
 func (g *RogueGame) fall(obj *Object, pr bool) {
 	if fpos, ok := g.fallpos(obj.Pos); ok {
 		pp := g.Level.At(fpos.Y, fpos.X)
-		pp.Ch = obj.Type
+		pp.Ch = obj.Kind.Glyph()
+
 		obj.Pos = fpos
-		if g.cansee(fpos.Y, fpos.X) {
+		if g.canSee(fpos.Y, fpos.X) {
 			if pp.Monst != nil {
-				pp.Monst.OldCh = obj.Type
+				pp.Monst.OldCh = obj.Kind.Glyph()
 			} else {
-				g.mvaddch(fpos.Y, fpos.X, obj.Type)
+				g.mvaddch(fpos.Y, fpos.X, obj.Kind.Glyph())
 			}
 		}
-		attachObj(&g.Level.Objects, obj)
+
+		g.Level.AddObject(obj)
+
 		return
 	}
+
 	if pr {
 		if g.HasHit {
 			g.endmsg()
 			g.HasHit = false
 		}
+
 		g.msg("the %s vanishes as it hits the ground",
 			g.Items.Weapons[obj.Which].Name)
 	}
@@ -92,73 +107,78 @@ func (g *RogueGame) hitMonster(mp Coord, obj *Object) bool {
 // wield pulls out a certain weapon (weapons.c wield).
 func (g *RogueGame) wield() {
 	p := &g.Player
+
 	oweapon := p.CurWeapon
 	if !g.dropCheck(p.CurWeapon) {
 		p.CurWeapon = oweapon
-		return
-	}
-	p.CurWeapon = oweapon
-	obj := g.getItem("wield", int(Weapon))
-	if obj == nil {
-		g.After = false
-		return
-	}
-	if obj.Type == Armor {
-		g.msg("you can't wield armor")
-		g.After = false
-		return
-	}
-	if g.isCurrent(obj) {
-		g.After = false
+
 		return
 	}
 
-	sp := g.invName(obj, true)
-	p.CurWeapon = obj
-	if !g.Options.Terse {
-		g.addmsg("you are now ")
+	p.CurWeapon = oweapon
+
+	obj, ok := g.promptPackItem("wield", KindWeapon)
+	if !ok {
+		g.After = false
+
+		return
 	}
+
+	if obj.Kind == KindArmor {
+		g.msg("you can't wield armor")
+		g.After = false
+
+		return
+	}
+
+	if g.isCurrent(obj) {
+		g.After = false
+
+		return
+	}
+
+	sp := g.inventoryName(obj, true)
+	p.CurWeapon = obj
+
+	if !g.Options.Terse {
+		g.addmsgf("you are now ")
+	}
+
 	g.msg("wielding %s (%c)", sp, obj.PackCh)
 }
 
-// initWeaps is the weapons.c init_dam[] table.
-var initWeaps = [MaxWeapons]struct {
-	dam    string // damage when wielded
-	hrl    string // damage when thrown
-	launch int    // launching weapon
+// weaponSetup is one row of the weapons.c init_dam[] table (see
+// gameData.initWeaps).
+type weaponSetup struct {
+	dam    DiceSpec   // damage when wielded
+	hrl    DiceSpec   // damage when thrown
+	launch WeaponKind // launching weapon
 	flags  ObjFlags
-}{
-	{"2x4", "1x3", noWeapon, 0},                // Mace
-	{"3x4", "1x2", noWeapon, 0},                // Long sword
-	{"1x1", "1x1", noWeapon, 0},                // Bow
-	{"1x1", "2x3", Bow, IsMany | IsMissl},      // Arrow
-	{"1x6", "1x4", noWeapon, IsMissl},          // Dagger
-	{"4x4", "1x2", noWeapon, 0},                // 2h sword
-	{"1x1", "1x3", noWeapon, IsMany | IsMissl}, // Dart
-	{"1x2", "2x4", noWeapon, IsMany | IsMissl}, // Shuriken
-	{"2x3", "1x6", noWeapon, IsMissl},          // Spear
 }
 
 // initWeapon sets up a new weapon (weapons.c init_weapon).
-func (g *RogueGame) initWeapon(weap *Object, which int) {
-	iwp := &initWeaps[which]
-	weap.Type = Weapon
-	weap.Which = which
+func (g *RogueGame) initWeapon(weap *Object, which WeaponKind) {
+	iwp := &g.data.initWeaps[which]
+	weap.Kind = KindWeapon
+	weap.Which = int(which)
 	weap.Damage = iwp.dam
 	weap.HurlDmg = iwp.hrl
 	weap.Launch = iwp.launch
 	weap.Flags = iwp.flags
 	weap.HPlus = 0
+
 	weap.DPlus = 0
-	if which == Dagger {
+
+	switch {
+	case which == WeaponDagger:
 		weap.Count = g.rnd(4) + 2
 		weap.Group = g.Items.Group
 		g.Items.Group++
-	} else if weap.Flags.Has(IsMany) {
+	case weap.Flags.Has(Stackable):
 		weap.Count = g.rnd(8) + 8
 		weap.Group = g.Items.Group
 		g.Items.Group++
-	} else {
+	default:
 		weap.Count = 1
 		weap.Group = 0
 	}
@@ -170,6 +190,7 @@ func num(n1, n2 int, typ byte) string {
 	if typ == Weapon {
 		out += fmt.Sprintf(",%+d", n2)
 	}
+
 	return out
 }
 
@@ -177,7 +198,9 @@ func num(n1, n2 int, typ byte) string {
 // (weapons.c fallpos).
 func (g *RogueGame) fallpos(pos Coord) (Coord, bool) {
 	var newpos Coord
+
 	cnt := 0
+
 	for y := pos.Y - 1; y <= pos.Y+1; y++ {
 		for x := pos.X - 1; x <= pos.X+1; x++ {
 			// check to make certain the spot is empty, if it is, put the
@@ -187,6 +210,7 @@ func (g *RogueGame) fallpos(pos Coord) (Coord, bool) {
 				y < 0 || x < 0 {
 				continue
 			}
+
 			ch := g.Level.Char(y, x)
 			if ch == Floor || ch == Passage {
 				if cnt++; g.rnd(cnt) == 0 {
@@ -196,5 +220,6 @@ func (g *RogueGame) fallpos(pos Coord) (Coord, bool) {
 			}
 		}
 	}
+
 	return newpos, cnt != 0
 }

game/wizard.go

@@ -8,190 +8,217 @@ package game
 // create_obj).
 func (g *RogueGame) createObj() {
 	obj := newObject()
+
 	g.msg("type of item: ")
-	obj.Type = g.readchar()
+	obj.Kind = objectKindForGlyph(g.readchar())
 	g.Msgs.Mpos = 0
-	g.msg("which %c do you want? (0-f)", obj.Type)
+	g.msg("which %c do you want? (0-f)", obj.Kind.Glyph())
+
 	ch := g.readchar()
 	if isDigit(ch) {
 		obj.Which = int(ch - '0')
 	} else {
 		obj.Which = int(ch-'a') + 10
 	}
+
 	obj.Group = 0
 	obj.Count = 1
 	g.Msgs.Mpos = 0
-	switch {
-	case obj.Type == Weapon || obj.Type == Armor:
+
+	switch obj.Kind {
+	case KindWeapon, KindArmor:
+		g.createWeaponArmor(obj)
+	case KindRing:
+		g.createRing(obj)
+	case KindWand:
+		g.fixStick(obj)
+	case KindGold:
+		g.msg("how much?")
+
+		buf := ""
+		if g.getStr(&buf, g.scr.Std) == Norm {
+			obj.GoldValue = cAtoi(buf)
+		}
+	}
+
+	g.addPack(obj, false)
+}
+
+// createWeaponArmor sets up a wizard-created weapon or armor with an
+// optional blessing (the weapon/armor arm of wizard.c create_obj).
+func (g *RogueGame) createWeaponArmor(obj *Object) {
+	g.msg("blessing? (+,-,n)")
+	bless := g.readchar()
+	g.Msgs.Mpos = 0
+
+	if bless == '-' {
+		obj.Flags.Set(Cursed)
+	}
+
+	if obj.Kind == KindWeapon {
+		g.initWeapon(obj, WeaponKind(obj.Which))
+
+		if bless == '-' {
+			obj.HPlus -= g.rnd(3) + 1
+		}
+
+		if bless == '+' {
+			obj.HPlus += g.rnd(3) + 1
+		}
+
+		return
+	}
+
+	obj.ArmorClass = g.data.aClass[obj.Which]
+	if bless == '-' {
+		obj.ArmorClass += g.rnd(3) + 1
+	}
+
+	if bless == '+' {
+		obj.ArmorClass -= g.rnd(3) + 1
+	}
+}
+
+// createRing sets up a wizard-created ring, prompting for a bonus on
+// the bonus rings (the ring arm of wizard.c create_obj).
+func (g *RogueGame) createRing(obj *Object) {
+	switch obj.RingKind() {
+	case RingProtection, RingAddStrength, RingDexterity, RingIncreaseDamage:
 		g.msg("blessing? (+,-,n)")
 		bless := g.readchar()
 		g.Msgs.Mpos = 0
+
 		if bless == '-' {
-			obj.Flags.Set(IsCursed)
-		}
-		if obj.Type == Weapon {
-			g.initWeapon(obj, obj.Which)
-			if bless == '-' {
-				obj.HPlus -= g.rnd(3) + 1
-			}
-			if bless == '+' {
-				obj.HPlus += g.rnd(3) + 1
-			}
+			obj.Flags.Set(Cursed)
+			obj.Bonus = -1
 		} else {
-			obj.Arm = aClass[obj.Which]
-			if bless == '-' {
-				obj.Arm += g.rnd(3) + 1
-			}
-			if bless == '+' {
-				obj.Arm -= g.rnd(3) + 1
-			}
-		}
-	case obj.Type == Ring:
-		switch obj.Which {
-		case RProtect, RAddStr, RAddHit, RAddDam:
-			g.msg("blessing? (+,-,n)")
-			bless := g.readchar()
-			g.Msgs.Mpos = 0
-			if bless == '-' {
-				obj.Flags.Set(IsCursed)
-				obj.Arm = -1
-			} else {
-				obj.Arm = g.rnd(2) + 1
-			}
-		case RAggr, RTeleport:
-			obj.Flags.Set(IsCursed)
-		}
-	case obj.Type == Stick:
-		g.fixStick(obj)
-	case obj.Type == Gold:
-		g.msg("how much?")
-		buf := ""
-		if g.getStr(&buf, g.scr.Std) == Norm {
-			obj.SetGoldVal(cAtoi(buf))
+			obj.Bonus = g.rnd(2) + 1
 		}
+	case RingAggravateMonsters, RingTeleportation:
+		obj.Flags.Set(Cursed)
 	}
-	g.addPack(obj, false)
 }
 
 // showMap prints out the whole map for the wizard (wizard.c show_map).
 func (g *RogueGame) showMap() {
 	hw := g.scr.Hw
 	hw.Clear()
+
 	for y := 1; y < NumLines-1; y++ {
-		for x := 0; x < NumCols; x++ {
-			real := g.Level.FlagsAt(y, x).Has(FReal)
-			if !real {
+		for x := range NumCols {
+			isReal := g.Level.FlagsAt(y, x).Has(FReal)
+			if !isReal {
 				hw.Standout(true)
 			}
+
 			hw.MvAddCh(y, x, g.Level.Char(y, x))
-			if !real {
+
+			if !isReal {
 				hw.Standout(false)
 			}
 		}
 	}
+
 	g.showWin("---More (level map)---")
 }
 
 // whatis identifies what a certain object is (wizard.c whatis).
-func (g *RogueGame) whatis(insist bool, typ int) {
+func (g *RogueGame) whatis(insist bool, kind ObjectKind) {
 	p := &g.Player
 	if len(p.Pack) == 0 {
 		g.msg("you don't have anything in your pack to identify")
+
 		return
 	}
 
-	var obj *Object
-	for {
-		obj = g.getItem("identify", typ)
-		if !insist {
-			break
-		}
-		if g.NObjs == 0 {
-			return
-		}
-		if obj == nil {
-			g.msg("you must identify something")
-		} else if typ != 0 && int(obj.Type) != typ &&
-			!(typ == RorS && (obj.Type == Ring || obj.Type == Stick)) {
-			g.msg("you must identify a %s", typeName(typ))
-		} else {
-			break
-		}
-	}
-
-	if obj == nil {
+	obj, ok := g.whatisPick(insist, kind)
+	if !ok {
 		return
 	}
 
-	switch obj.Type {
-	case Scroll:
+	switch obj.Kind {
+	case KindScroll:
 		setKnow(obj, g.Items.Scrolls[:])
-	case Potion:
+	case KindPotion:
 		setKnow(obj, g.Items.Potions[:])
-	case Stick:
+	case KindWand:
 		setKnow(obj, g.Items.Sticks[:])
-	case Weapon, Armor:
-		obj.Flags.Set(IsKnow)
-	case Ring:
+	case KindWeapon, KindArmor:
+		obj.Flags.Set(Known)
+	case KindRing:
 		setKnow(obj, g.Items.Rings[:])
 	}
-	g.msg("%s", g.invName(obj, false))
+
+	g.msg("%s", g.inventoryName(obj, false))
+}
+
+// whatisPick prompts for the item to identify, re-asking until a
+// matching one is chosen when insist is set; ok is false when the
+// player gives up (the prompt loop of wizard.c whatis).
+func (g *RogueGame) whatisPick(insist bool, kind ObjectKind) (*Object, bool) {
+	for {
+		obj, _ := g.promptPackItem("identify", kind)
+
+		if !insist {
+			return obj, obj != nil
+		}
+
+		if g.NObjs == 0 {
+			return nil, false
+		}
+
+		if obj == nil {
+			g.msg("you must identify something")
+
+			continue
+		}
+
+		if !matchesFilter(kind, obj) {
+			g.msg("you must identify a %s", kind)
+
+			continue
+		}
+
+		return obj, true
+	}
 }
 
 // setKnow sets things up when we really know what a thing is (wizard.c
 // set_know).
 func setKnow(obj *Object, info []ObjInfo) {
 	info[obj.Which].Know = true
-	obj.Flags.Set(IsKnow)
+	obj.Flags.Set(Known)
 	info[obj.Which].Guess = ""
 }
 
-// typeNameTable is the wizard.c type_name static tlist.
-var typeNameTable = []struct {
-	ch   int
-	desc string
-}{
-	{int(Potion), "potion"},
-	{int(Scroll), "scroll"},
-	{int(Food), "food"},
-	{RorS, "ring, wand or staff"},
-	{int(Ring), "ring"},
-	{int(Stick), "wand or staff"},
-	{int(Weapon), "weapon"},
-	{int(Armor), "suit of armor"},
-}
-
-// typeName returns the name of an object type (wizard.c type_name).
-func typeName(typ int) string {
-	for _, hp := range typeNameTable {
-		if typ == hp.ch {
-			return hp.desc
-		}
-	}
-	return ""
-}
+// The C type_name()/tlist table is gone: ObjectKind.String() carries the
+// same vocabulary.
 
 // teleport bamfs the hero someplace else (wizard.c teleport).
 func (g *RogueGame) teleport() {
 	p := &g.Player
 	g.mvaddch(p.Pos.Y, p.Pos.X, g.floorAt())
-	c, _ := g.findFloor(nil, 0, true)
-	if g.roomin(c) != p.Room {
+
+	c, _ := g.findFloor(true)
+	if g.roomIn(c) != p.Room {
 		g.leaveRoom(p.Pos)
 		p.Pos = c
 		g.enterRoom(p.Pos)
 	} else {
 		p.Pos = c
+
 		g.look(true)
 	}
+
 	g.mvaddch(p.Pos.Y, p.Pos.X, PlayerCh)
 	// turn off ISHELD in case teleportation was done while fighting a
 	// Flytrap
-	if p.On(IsHeld) {
-		p.Flags.Clear(IsHeld)
+	if p.On(Held) {
+		p.Flags.Clear(Held)
 		p.VfHit = 0
-		g.Monsters['F'-'A'].Stats.Dmg = "000x0"
+		g.Monsters['F'-'A'].Stats.Dmg = dice("000x0")
 	}
+
 	g.NoMove = 0
 	g.Count = 0
 	g.Running = false

go.mod

@@ -1,10 +1,11 @@
-module sneak.berlin/go/rogue
+module git.eeqj.de/sneak/rgoue
 
 go 1.25.7
 
+require github.com/gdamore/tcell/v2 v2.13.10
+
 require (
 	github.com/gdamore/encoding v1.0.1 // indirect
-	github.com/gdamore/tcell/v2 v2.13.10 // indirect
 	github.com/lucasb-eyer/go-colorful v1.3.0 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	golang.org/x/sys v0.38.0 // indirect

term/tcell.go

@@ -5,13 +5,15 @@
 package term
 
 import (
+	"context"
+	"errors"
 	"fmt"
 	"os"
 	"os/exec"
 
 	"github.com/gdamore/tcell/v2"
 
-	"sneak.berlin/go/rogue/game"
+	"git.eeqj.de/sneak/rgoue/game"
 )
 
 // Tcell renders game Windows on a tcell screen and turns key events into
@@ -21,6 +23,9 @@ type Tcell struct {
 	last   *game.Window // last rendered window, for resize redraws
 }
 
+// ErrScreenTooSmall reports a terminal below the required 80x24.
+var ErrScreenTooSmall = errors.New("screen too small")
+
 // New initializes the terminal. The screen must be at least 80x24, as the
 // C game required.
 func New() (*Tcell, error) {
@@ -28,16 +33,22 @@ func New() (*Tcell, error) {
 	if err != nil {
 		return nil, err
 	}
-	if err := s.Init(); err != nil {
-		return nil, err
+
+	initErr := s.Init()
+	if initErr != nil {
+		return nil, initErr
 	}
+
 	w, h := s.Size()
 	if h < game.NumLines || w < game.NumCols {
 		s.Fini()
-		return nil, fmt.Errorf("sorry, the screen must be at least %dx%d",
-			game.NumLines, game.NumCols)
+
+		return nil, fmt.Errorf("sorry, %w: %dx%d required",
+			ErrScreenTooSmall, game.NumCols, game.NumLines)
 	}
+
 	s.HideCursor()
+
 	return &Tcell{screen: s}, nil
 }
 
@@ -49,17 +60,21 @@ func (t *Tcell) Fini() {
 // Render blits a game window to the terminal (curses refresh).
 func (t *Tcell) Render(w *game.Window) {
 	t.last = w
+
 	rows, cols := w.Size()
-	for y := 0; y < rows; y++ {
-		for x := 0; x < cols; x++ {
+	for y := range rows {
+		for x := range cols {
 			ch, standout := w.CellAt(y, x)
+
 			style := tcell.StyleDefault
 			if standout {
 				style = style.Reverse(true)
 			}
+
 			t.screen.SetContent(x, y, rune(ch), nil, style)
 		}
 	}
+
 	t.screen.Show()
 }
 
@@ -74,62 +89,114 @@ func (t *Tcell) ReadChar() byte {
 				t.Render(t.last)
 			}
 		case *tcell.EventKey:
-			switch ev.Key() {
-			case tcell.KeyUp:
-				return 'k'
-			case tcell.KeyDown:
-				return 'j'
-			case tcell.KeyLeft:
-				return 'h'
-			case tcell.KeyRight:
-				return 'l'
-			case tcell.KeyHome:
-				return 'y'
-			case tcell.KeyPgUp:
-				return 'u'
-			case tcell.KeyEnd:
-				return 'b'
-			case tcell.KeyPgDn:
-				return 'n'
-			case tcell.KeyEnter:
-				return '\n'
-			case tcell.KeyEscape:
-				return game.Escape
-			case tcell.KeyBackspace, tcell.KeyBackspace2:
-				return 8
-			case tcell.KeyDelete:
-				return 0x7f
-			case tcell.KeyTab:
-				return '\t'
-			case tcell.KeyCtrlC:
-				return 3
-			default:
-				if ev.Key() >= tcell.KeyCtrlA && ev.Key() <= tcell.KeyCtrlZ {
-					return byte(ev.Key())
-				}
-				if r := ev.Rune(); r > 0 && r < 0x80 {
-					return byte(r)
-				}
+			if b, ok := translateKey(ev); ok {
+				return b
 			}
 		}
 	}
 }
 
+// translateKey converts a key event to a game input byte; ok is false
+// for keys the C game does not understand.
+func translateKey(ev *tcell.EventKey) (byte, bool) {
+	if b, ok := namedKey(ev.Key()); ok {
+		return b, true
+	}
+
+	if ev.Key() >= tcell.KeyCtrlA && ev.Key() <= tcell.KeyCtrlZ {
+		return byte(ev.Key()), true //nolint:gosec // G115: 1..26 fits
+	}
+
+	if r := ev.Rune(); r > 0 && r < 0x80 {
+		return byte(r), true
+	}
+
+	return 0, false
+}
+
+// namedKey translates tcell's navigation and editing keys to the single
+// bytes the C game reads (arrows become hjkl, etc.); ok is false for
+// keys handled elsewhere.
+func namedKey(k tcell.Key) (byte, bool) {
+	if b, ok := motionKey(k); ok {
+		return b, true
+	}
+
+	return editingKey(k)
+}
+
+// motionKey translates the arrow and paging keys to Rogue's movement
+// letters (tcell.go ReadChar).
+func motionKey(k tcell.Key) (byte, bool) {
+	switch k {
+	case tcell.KeyUp:
+		return 'k', true
+	case tcell.KeyDown:
+		return 'j', true
+	case tcell.KeyLeft:
+		return 'h', true
+	case tcell.KeyRight:
+		return 'l', true
+	case tcell.KeyHome:
+		return 'y', true
+	case tcell.KeyPgUp:
+		return 'u', true
+	case tcell.KeyEnd:
+		return 'b', true
+	case tcell.KeyPgDn:
+		return 'n', true
+	}
+
+	return 0, false
+}
+
+// editingKey translates the editing and control keys to their C0 codes
+// (tcell.go ReadChar).
+func editingKey(k tcell.Key) (byte, bool) {
+	switch k {
+	case tcell.KeyEnter:
+		return '\n', true
+	case tcell.KeyEscape:
+		return game.Escape, true
+	case tcell.KeyBackspace, tcell.KeyBackspace2:
+		return 8, true
+	case tcell.KeyDelete:
+		return 0x7f, true
+	case tcell.KeyTab:
+		return '\t', true
+	case tcell.KeyCtrlC:
+		return 3, true
+	}
+
+	return 0, false
+}
+
 // ShellEscape suspends the screen and runs the user's shell (main.c
 // shell + md_shellescape).
 func (t *Tcell) ShellEscape() {
-	if err := t.screen.Suspend(); err != nil {
+	err := t.screen.Suspend()
+	if err != nil {
 		return
 	}
+
 	shell := os.Getenv("SHELL")
 	if shell == "" {
 		shell = "/bin/sh"
 	}
-	fmt.Println("[Entering shell; exit to return to the game]")
-	cmd := exec.Command(shell)
+
+	_, _ = fmt.Fprintln(os.Stdout,
+		"[Entering shell; exit to return to the game]")
+
+	// The shell session has no deadline by design; Background context.
+	cmd := exec.CommandContext(context.Background(), //nolint:gosec // G204: the user's own $SHELL
+		shell)
 	cmd.Stdin = os.Stdin
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
-	cmd.Run()
-	t.screen.Resume()
+	_ = cmd.Run() // best effort: the shell is the user's business
+
+	resumeErr := t.screen.Resume()
+	if resumeErr != nil {
+		panic(resumeErr) // terminal resume failure is unrecoverable
+	}
 }