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js-on-sx: bail out of array set/length at 2^32-1 instead of padding
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arr[4294967295] = 'x' and arr.length = 4294967295 were padding
the SX list with js-undefined for ~4 billion entries — instant
timeout. Per ES spec, indices >= 2^32-1 aren't array indices
anyway (regular properties, which we can't store on lists).
Added (>= i 4294967295) bail clauses to js-list-set! and the
length setter.
built-ins/Array: 21/45 → 23/45 (5 timeouts → 2).
conformance.sh: 148/148.
This commit is contained in:
giles
2026-05-08 05:31:50 +00:00
parent 0cfaeb9136
commit 16f7a14506
4 changed files with 31 additions and 27 deletions
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plans/js-on-sx.md
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@@ -158,6 +158,8 @@ Each item: implement → tests → update progress. Mark `[x]` when tests green.
Append-only record of completed iterations. Loop writes one line per iteration: date, what was done, test count delta.
- 2026-05-08 — **Out-of-range array indices and lengths no longer hang.** `arr[4294967295] = 'x'` and `arr.length = 4294967295` were padding the SX list with `js-undefined` for ~4 billion entries — guaranteed timeout. Per ES spec, indices ≥ 2^32-1 aren't array indices (they're regular properties, which we can't store on a list). Added a `(>= i 4294967295)` bail-out clause to both `js-list-set!` (numeric index path) and the `length` setter; both now no-op at that bound. Removed 5 of the 7 Array timeouts. built-ins/Array: 21/45 → 23/45. conformance.sh: 148/148.
- 2026-05-08 — **Built-in `.length` returns spec-defined values for variadic functions.** `String.fromCharCode.length`, `Math.max.length`, `Array.from.length` were all returning `0` because the underlying SX lambdas use `&rest args` with no required params — but the spec assigns each built-in a specific length (`fromCharCode === 1`, `max === 2`, etc.). Added `js-builtin-fn-length` that maps the unmapped JS name to its spec length (12 entries covering fromCharCode, fromCodePoint, raw, of, from, isArray, max, min, hypot, atan2, imul, pow). `js-fn-length` consults this table first and falls back to counting real params. built-ins/String: 79/99 → 80/99, built-ins/Array: 20/45 → 21/45. conformance.sh: 148/148.
- 2026-05-08 — **`Object.prototype.toString` dispatches by [[Class]].** Was hardcoded to `"[object Object]"` for everything; per ES it should return `"[object Array]"`, `"[object Function]"`, `"[object Number]"`, etc. based on the receiver's class. Added `js-object-tostring-class` helper that switches on `(type-of v)` and on dict-internal markers (`__js_string_value__`, `__js_number_value__`, `__js_boolean_value__`, `__callable__`). Also added prototype-identity checks so `Object.prototype.toString.call(Number.prototype)` returns `"[object Number]"` (similar for String/Boolean/Array). built-ins/Array: 18/45 → 20/45, built-ins/Number: 43/50 → 44/50. conformance.sh: 148/148.