`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>
Closes groups A, C, D, E, F, H and J of TODO.md section 4, plus RESTORE and
RENUMBER, and closes section 6 -- all seventeen reference defects. Seven of
those turned out to have been fixed or never ported and nobody had written it
down; the audit records the evidence for each.
Two of the seventeen were real. math_plus mutated its left operand when the
operand was mutable, so A# + 1 could modify A#; it was gated on FOR/NEXT
coverage because NEXT relied on the mutation, so tests/for_next.c came first
and NEXT now writes the counter back itself. And the binary operators summed
both numeric fields of their right operand, which no BASIC program can reach
-- that one needed a test written against the value API.
Writing the tests turned up eight defects nobody had listed. Seven are fixed:
IF A = 2 THEN was a parse error; only == worked
IF ... AND ... was a parse error, because a condition parsed as one relation
IF A = 1 OR B = 2 THEN was silently always false, and so was IF A THEN
EXIT before any NEXT restarted the program and exhausted the variable pool
READ never found a DATA line above it, and swallowed the lines between
PRINT 2 + 2 at the prompt was filed as program text instead of answering
a short read discarded its bytes, so COPY produced empty files
every verb taking an argument list said "peek() returned nil token!" on none
The eighth is not fixed and cannot be quietly: a FOR whose step overshoots
runs its body one extra time, and FOR I = 1 TO 1 runs it zero times. The two
errors cancel for a step of 1, which is why neither was noticed. Correcting
them changes the expected output of a checked-in acceptance file, and
tests/reference/README.md forbids editing one to suit this interpreter. It is
tests/for_semantics.c in AKBASIC_KNOWN_FAILING_TESTS, asserting the correct
contract, and TODO.md items 19 and 20.
Sprites are real libakgl actors with a renderfunc of their own, because
akgl_actor_render draws every sprite square and an actor has no per-axis
scale. Both are filed upstream. SPRSAV takes an image file, an SSHAPE handle
or a 63-element integer array -- a string here cannot hold a zero byte.
Verbs that need hardware that does not exist are refused by name with the
reason rather than faked: SYS, HEADER, COLLECT, BACKUP, BOOT, FILTER, and
DIRECTORY, which is refused for a missing libakstdlib wrapper filed upstream.
94 tests in the default build, 93 with SDL, 94 under ASan and UBSan, doxygen
clean. The Go acceptance corpus stayed green throughout.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
