Andrew Kesterson
5d33237eed
`akbasic_parse_for()` and `akbasic_parse_do()` create their environment while the line is *parsed*; whether to skip it is decided afterwards, when the line is evaluated. So a loop inside a block that was not taken pushed a scope, its body was skipped, and the `NEXT` or `LOOP` that would have popped it was skipped too. Nothing else ever would. At the top level that exhausted the pool after thirty-two skips. Inside a routine it was far more confusing: the orphan sat between the routine and its caller, so the `RETURN` after the block reported "RETURN outside the context of GOSUB" from a routine that plainly *was* entered by a `GOSUB` -- naming the one construct that was not at fault, which is why it cost an evening to find. The skip now releases what parsing pushed. **Narrower than it first looks.** Releasing on any skip breaks tests/reference/language/flowcontrol/nestedforloopwaitingforcommand.bas: a zero-iteration `FOR` skips its body by the same mechanism, and there the orphan is load-bearing -- it absorbs the inner `NEXT` so the outer `NEXT` still finds its own `FOR`. Releasing it turns that case into "NEXT outside the context of FOR". So the release is conditional on the skip being a *block* skip, which is decidable because nothing inside a skipped block ever runs to arm a `NEXT` wait. Both halves are asserted side by side in tests/structure_verbs.c, the second one citing the golden case that caught it. The forty-skip case names its own step budget: a skipped line is not free, and forty passes over a five-line block cost about 2700 steps against the shared runner's 2000. Chapter 18's trap 3 becomes history rather than a warning, and the note in Step 5 that called `GOTO`-guarded loops "not a style choice" now says why the shape is kept anyway. TODO.md section 9 item 2, struck. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
13 KiB
13 KiB