lua: generic for-in; ipairs/pairs/next; arity-tolerant fns +9 tests

plans/lua-on-sx.md

@@ -62,7 +62,7 @@ Each item: implement → tests → tick box → update progress log.
 ### Phase 4 — metatables + error handling (next run)
 - [x] Metatable dispatch: `__index`, `__newindex`, `__add`/`__sub`/…, `__eq`, `__lt`, `__call`, `__tostring`, `__len`
 - [x] `pcall`/`xpcall`/`error` via handler-bind
-- [ ] Generic `for … in …`
+- [x] Generic `for … in …`
 
 ### Phase 5 — coroutines (the showcase)
 - [ ] `coroutine.create`/`.resume`/`.yield`/`.status`/`.wrap` via `perform`/`cek-resume`
@@ -82,6 +82,7 @@ Each item: implement → tests → tick box → update progress log.
 
 _Newest first. Agent appends on every commit._
 
+- 2026-04-24: lua: generic `for … in …` — parser split (`=` → num, else `in`), new `lua-for-in` node, transpile to `let`-bound `f,s,var` + recursive `__for_loop`. Added `ipairs`/`pairs`/`next`/`lua-arg` globals. Lua fns now arity-tolerant (`&rest __args` + indexed bind) — needed because generic for always calls iter with 2 args. Noted early-return-in-nested-block as pre-existing limitation. 265 tests.
 - 2026-04-24: lua: `pcall`/`xpcall`/`error` via SX `guard` + `raise`. Added `lua-apply` (arity-dispatch 0-8, apply fallback) because SX `apply` re-wraps raises as "Unhandled exception". Table payloads preserved (`error({code = 42})`). 256 total tests.
 - 2026-04-24: lua: phase 4 — metatable dispatch (`__index`/`__newindex`/arith/compare/`__call`/`__len`), `setmetatable`/`getmetatable`/`type` globals, OO `self:method` pattern. Transpile routes all calls through `lua-call` (stashed `sx-apply-ref` to dodge user-shadowing of SX `apply`). Skipped `__tostring` (needs `tostring()` builtin). 247 total tests.
 - 2026-04-24: lua: PUC-Rio scoreboard baseline — 0/16 runnable pass (0.0%). Top modes: 14× parse error, 1× `print` undef, 1× vararg transpile. Phase 3 complete.
@@ -100,3 +101,7 @@ _Newest first. Agent appends on every commit._
 _Shared-file issues that need someone else to fix. Minimal repro only._
 
 - _(none yet)_
+
+## Known limitations (own code, not shared)
+
+- **Early `return` inside nested block** — `if cond then return nil end ...rest` doesn't exit the enclosing function; `rest` runs anyway. Use `if cond then return X else return Y end` instead. Likely needs guard+raise sentinel for proper fix.