js-on-sx: parse-time SyntaxError on illegal break/continue/return; void evaluates expr

plans/js-on-sx.md

@@ -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.
 
+- 2026-05-10 — **Parse-time SyntaxError for `break`/`continue` outside loops/switches and `return` outside functions; `void <expr>` evaluates `<expr>` for side effects.** Parser tracks `:loop-depth`, `:switch-depth`, and `:fn-depth` on the state dict (initialized to 0). `jp-parse-while-stmt`, `jp-parse-do-while-stmt`, `jp-parse-for-stmt` (both for-of/in and C-for) bump `:loop-depth` around body parsing; `jp-parse-switch-stmt` bumps `:switch-depth`; new `jp-parse-fn-body` and `jp-parse-arrow-body` save+reset loop/switch depth and bump `:fn-depth` (so `break` inside an outer loop's nested function is rejected). Bare `break` requires `loop-depth > 0 OR switch-depth > 0`; bare `continue` requires `loop-depth > 0`; `return` requires `fn-depth > 0`. Separately, `void <expr>` was compiling to just `:js-undefined` (dropping the expression entirely); now `(begin <expr> :js-undefined)` so side effects fire. Result: language/statements/return 4/15 → 14/15 (+10). statements/break 9/20 → 12/20. statements/continue 12/24 → 15/24. expressions/void 7/9 → 8/9. conformance.sh: 148/148.
+
 - 2026-05-10 — **`Math.hypot` and `Math.cbrt` honour spec edges for NaN, ±Infinity, and ±0.** `Math.hypot(NaN, Infinity)` was returning NaN instead of +Infinity (spec: any ±Infinity arg dominates NaN). Rewrote `js-math-hypot` to scan args once tracking inf/nan flags, return +Infinity if any arg is ±Infinity, else NaN if any was NaN, else `sqrt(sum of squares)`. `Math.cbrt(NaN)` was 0 (because `pow(NaN, 1/3)` produced 0 in our path); also `Math.cbrt(-0)` returned +0 instead of -0. Added explicit short-circuits: NaN→NaN, ±Infinity→arg, ±0→arg, plus changed `(/ 1 3)` (rational) to `(/ 1.0 3.0)` (inexact) to avoid rational fractional-power oddities. Result: built-ins/Math/hypot 9/11 → 10/11. Math/cbrt 3/4 → 4/4. conformance.sh: 148/148.
 
 - 2026-05-10 — **`globalThis.globalThis === globalThis`; `Number.prototype.toFixed` honours digit-range and ≥1e21 fallback.** (1) `globalThis` was bound to `nil` in the global object literal (originally to dodge an inspect-cycle hang) — added `(dict-set! js-global "globalThis" js-global)` after the literal so `globalThis.globalThis === globalThis` per spec. (2) `Number.prototype.toFixed` rewrites: RangeError when fractionDigits is NaN or outside `[0,100]` (was silently producing garbage), and for `|x| >= 1e21` returns `js-number-to-string` (the value's own ToString) per spec step 9. conformance.sh: 148/148.