89fe0fb0b3
Add a '$EXTERN NAME(ARGTYPES) AS RET pragma so compiled BASIC can call C functions directly, the natural follow-up to Level 1 (--emit-obj / --main-name). The pragma is an apostrophe comment, so the interpreter ignores it while the compiler registers it. Map INTEGER/SINGLE/DOUBLE/STRING to int16_t/float/double/const char* at the boundary: a string argument crosses as a temporary C copy that is freed after the call, and a string return is copied into the pool. The call name is matched case-insensitively but emitted as the C symbol with the case written in the pragma. Names are recognized before parse_var() truncates identifiers to two significant characters, so multi-character C function names work. A string return that aliases a char* argument is copied before the argument temporaries are freed, which avoids a use-after-free. Over-supplied arguments are consumed without desyncing the token stream and warn on arity mismatch. Docs: getting-started.md "Foreign Functions from BASIC". Test: tests/run_ffi_test.sh, wired into CI. 63/63 compiler, 72/72 interpreter, 68/68 compat still pass. Also refile the roadmap "Next Up" backlog as git-bug issues and prune docs/roadmap.md to point at git-bug as the source of truth for planned work. Co-authored-by: Eremey Valetov <evvaletov@users.noreply.github.com>
27 lines
821 B
C
27 lines
821 B
C
/* C functions called from extern_demo.bas via '$EXTERN pragmas. */
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#include <stdint.h>
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#include <math.h>
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#include <stdio.h>
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#include <ctype.h>
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int16_t Cadd(int16_t a, int16_t b) { return (int16_t)(a + b); }
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double Chypot(double a, double b) { return hypot(a, b); }
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int16_t Getn(void) { return 42; }
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const char *Greet(const char *who)
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{
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static char buf[128];
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snprintf(buf, sizeof buf, "Hello, %s!", who);
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return buf;
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}
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/* Returns its own argument pointer after modifying it in place. Exercises the
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* string-return path where the result aliases a C-string arg temporary — the
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* codegen must copy the result before freeing that temporary. */
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const char *Upcase(const char *s)
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{
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for (char *p = (char *)s; *p; p++)
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*p = (char)toupper((unsigned char)*p);
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return s;
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}
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