Drop the ':' before captures (for xs (x) / for 0..n (i)); the index
capture becomes the trailing open range (for xs, 0.. (x, i)). 136
headers across 26 files, mechanical.
Five headless tests (banner_layout, hit_test, swipe_commit,
swipe_intent, swipe_reshuffle) also gain a direct
#import "modules/ui/types.sx" — they named Point/Frame through a
transitive import, which bare visibility no longer permits.
Gates: sx build --target ios-sim main.sx links; tools/run_tests.sh
23/23.
Add swap + legality to the board model:
- swap(board, a, b): in-place, self-inverse cell exchange (trial then revert).
- adjacent(a, b): orthogonal-adjacency predicate (diagonal/gap = false).
- swap_legal(board, a, b): legal iff adjacent AND, after the trial swap, either
swapped cell participates in a 3+ match (reuses find_matches); leaves the
board unchanged. Non-adjacent/diagonal rejected before any match check.
- Cell/Swap structs + legal_swaps(board): all currently-legal swaps in a stable
row-major, right-before-down order; dump_swaps for deterministic snapshotting.
tests/swap_legality.sx asserts the predicate over hand-crafted boards (legal
3-run, no-match, non-adjacent, diagonal, only-the-other-gem-matches) and the
non-mutating revert; locks legal_swaps over the seeded board as a golden.
