2 Commits

Author	SHA1	Message	Date
Ishikawa	a29c7f34fe	Fix generator teardown leaks, add RETURN-in-GEN and LOOP conditions on DO EACH ... Review findings and follow-ups from PR #61 review: - runtime_generator.c: akbasic_runtime_release_generator() now releases the forGeneratorEnv of every scope it walks through. Abandoning a generator that was itself suspended inside a FOR EACH over another generator stranded the inner generator's pool slot; a loop doing so exhausted the twelve-slot pool and died far from the cause. - runtime.c/runtime.h: new akbasic_runtime_unwind_to_environment(), the shared teardown for the error unwinds in pump_generator() and call_function() -- both previously bare prev_environment() loops with the same suspended-generator blindness. - runtime_commands.c: bare RETURN standing in a GEN's own frame ends the generator exactly as END GEN does -- a GEN is a function at heart. RETURN with a value there is refused (values leave a GEN only through EMIT). The no-frame error message now says "GOSUB, DEF, or GEN". - runtime_structure.c: LOOP WHILE/UNTIL composes with DO EACH -- checked after each trip with the loop variable still holding that trip's value; a condition that stops the loop abandons the generator exactly as EXIT does. Previously the condition was silently ignored, while the verb reference documented it as working. - parser_commands.c: trailing tokens after the generator call on a FOR EACH/DO EACH line are refused at parse. Previously they sat unparsed and blew up only after the loop completed, when the parent scope resumed the line mid-statement -- an error at the loop's end pointing at its start. - tests/generators.c: pool-exhaustion tests for the nested-abandonment and LOOP-condition paths, RETURN semantics tests, and a direct test of the unwind primitive. Three new golden pairs cover RETURN, LOOP conditions and the misplaced-condition parse error. - docs: RETURN and LOOP-condition semantics in 04-control-flow.md and 11-verb-reference.md; corrected the self-recursion analogy (functions are re-entrant here). TODO.md 1.10 records the generator design decisions the code comments were already citing, plus the zero-arg parameter-list limitation. MAINTENANCE.md gains the abandoned-generators invariant those comments also cited. Co-Authored-By: Andrew Kesterson <andrew@aklabs.net> Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>	2026-08-06 11:55:59 -04:00
Tachikoma	f7e8d4b82b	Implement generators: GEN, EMIT, END GEN, FOR EACH and DO EACH (issue 57) ... Adds generator support per the plan in issue 57: - environment.h: isGenerator/generatorFn on a GEN call's own environment, isEachLoop and forGeneratorEnv on a FOR EACH/DO EACH loop's own environment. - runtime.c: splits akbasic_runtime_prev_environment() into akbasic_runtime_detach_environment() (return to parent without releasing) and akbasic_runtime_release_environment() (give variables and the pool slot back, on any environment); prev_environment() is now the two in sequence. akbasic_runtime_call_function() refuses to call a GEN like an ordinary function. - verbs.c/verbs.h/scanner: new keywords GEN, EMIT, EACH, IN and the compound verb "END GEN" (built by a new akbasic_parse_end(), the same trick akbasic_parse_print() uses for PRINT #). - parser_commands.c: akbasic_parse_gen() (modelled on multi-line DEF), akbasic_parse_end(), and EACH branches in akbasic_parse_for()/ akbasic_parse_do(). - runtime_generator.c (new): akbasic_cmd_gen, akbasic_cmd_emit, akbasic_cmd_end_gen, and the invoke/pump/release machinery FOR EACH, DO EACH, NEXT and LOOP share. EMIT walks up to the nearest isGenerator ancestor rather than assuming it is standing directly in the GEN's own call frame, because a GEN body may nest its own FOR/DO/GOSUB around an EMIT -- the issue's own ROOMOBJECTS example does exactly that. - runtime_commands.c/runtime_structure.c: EACH branches in cmd_for/cmd_do, matching EACH branches in cmd_next/cmd_loop, and forGeneratorEnv release on every path that can abandon a live generator (EXIT, a NEXT that pops for a mismatched loop variable). Deviates from the plan in one place: FunctionDef gained an isGenerator flag (not in the plan's field list) because refusing a GEN called like a function has to happen before anything is pushed. Relying on EMIT's own isGenerator check for that case doesn't work: akbasic_runtime_call_function() drives its own step loop the same way akbasic_runtime_pump_generator() does, and a BASIC-level error inside that loop is swallowed by process_line_run() as reported-but-not-propagated, so the call would silently "succeed" with a meaningless return value instead of failing. Also: a zero-argument parameter list is not supported by the DEF/GEN parameter parser this reuses (a pre-existing limitation, not generator-specific); every generator in the tests takes at least one parameter as a result. Tests: tests/generators.c (pool exhaustion under repeated EXIT, calling a GEN like a function, EMIT outside a GEN, self-recursion, sibling/nested invocations) and tests/language/flowcontrol/generators_*.bas -- the issue's own ROOMOBJECTS example in both loop shapes, an empty generator, non-numeric EMIT, nested/interleaved invocations, and three error-path golden cases. Docs: control-flow chapter 4 gets a GEN/EMIT/FOR EACH/DO EACH section, the verb reference gets GEN/EMIT/END GEN entries and updated FOR/DO/NEXT/LOOP/EXIT rows, and architecture chapter 14 documents the detach/release split and the two-environment generator invocation. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>	2026-08-06 10:02:43 -04:00