Baba.undo() restores the level before the last step or move (board snapshot:
objects in age order with ids, the id counter, and won; rules recompiled).
place clears the history. SpellGrid's undo throws/panics 'not supported'.
stackAt / stack_at lists a tile's kinds oldest first, on Baba and SpellGrid.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- Rename course/11-break-your-engine to 13-break-your-engine and update every
link and mention; start-module explains that Module 13 has no tests to start.
- tools/diff-tracks.mjs (npm run diff:tracks): stages both references of a
module, generates a seeded random SpellGrid level and script per seed, pipes
it to the Rust and TypeScript CLIs and diffs their output; crashes on one or
both sides fail. stagePlay takes a module number.
- register_assembled: the TypeScript track compared only the text of an
existing Assembled card, so a base re-registered with a new cost (or a
different split) silently rewrote the earlier card. It now compares every
field the engine reads, as Rust does (Modules 5-10).
New test_05_assemble_never_rewrites_an_earlier_card.
- SpellGrid CLIs: coordinates and chooser numbers are 1-9 plain digits in both
tracks (Rust accepted signs, TypeScript accepted "+2", "0x2", "1e0"); Rust
quotes card names verbatim instead of with Debug escapes; Rust joins the
minion list with "; " instead of rewriting ", ". Two new CLI tests per track.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- lessons 8 and 9 updated for the once-per-move rule, per-object negated
conversion and the new ordering tests
- tools/solve-spellgrid.mjs: breadth-first search over a SpellGrid level
with the TypeScript reference; --never-rule and --naive
- README, harness.md and the mentor skill know the new beat and module
Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>
Movement planned in full, then committed: a Planner builds a plan
(moving and destroyed ids) by running content's movement responses
(OPEN/SHUT, PUSH, STOP) for every step, rolling back failed branches.
Edge of level blocks; YOU objects move furthest-ahead first; rules are
reparsed once after movement. Harness: move/move_dir(Dir), posOf,
kindsAt. Expansion Drop: PULL as one word plus one content response.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
