Andrew Kesterson
fdb3421b2a
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`akbasic_runtime_call_function(obj, name, args, nargs, dest)`. The argument
binding is split out of the call-site handling, so
`akbasic_runtime_user_function()` becomes evaluate-the-leaves and then call the
same code -- and a verb that wants to hand a BASIC function four numbers has
somewhere to start, which it did not before. The only entry point took a parsed
AST call site, so calling a function required having been parsed as an
expression.
Behaviour-preserving: both suites pass unmodified. The one deliberate difference
is that the AST path now evaluates *all* the arguments before binding any of
them, where it used to interleave. That is the safer order and it is what
by-value passing means everywhere else -- interleaved, a later argument could see
an earlier one already in the callee's scope.
**Finding, filed as section 6 item 41: a multi-line `DEF` called outside a
running program does not run its body, and says nothing about it.**
DEF TRIPLE(N#)
T# = N# * 3
RETURN T#
PRINT TRIPLE(14)
At the REPL that prints "(UNDEFINED STRING REPRESENTATION FOR 0)". From a file
the same function answers 42. The multi-line body runs by spinning a line loop
guarded on `mode == AKBASIC_MODE_RUN`, which is true only of a program running
from a file; in REPL mode the loop is skipped and the result is the caller's
zeroed return slot. The single-expression form has no such loop, and every case
in tests/user_functions.c goes through run_program and is therefore in RUN mode,
which is most of why nobody had seen it.
**The obvious fix is wrong and I tried it.** Widening the guard to
`mode != AKBASIC_MODE_QUIT` makes the interpreter *hang* instead of answering
wrongly -- `akbasic_runtime_process_line_run()` does not advance a REPL-mode
runtime the way the loop assumes, so the environment never comes back. Trading a
silent wrong answer for a lock-up is worse, so it is reverted, the reasoning is
in a comment where the next person will try the same thing, and the fix is filed
rather than guessed at.
That bounds this entry point rather than blocking it: it reaches a multi-line
body while a program is running, which is exactly the case a verb calling a
callback is in. The new test asserts the single-expression form from C and says
in a comment why the multi-line one is not asserted, so the omission is a
statement rather than a gap.
What is still not done is the language half -- no verb takes a function, and
nothing resolves a bare word to a function rather than a label. Item 40 now says
so, and says it wants a verb that needs it rather than speculation.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EwxGB6TdoVvZ11KQQME9cL