regex_match.c

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/*
 * This file is part of the Fun programming language.
 * https://fun-lang.xyz/
 *
 * Copyright 2025 Johannes Findeisen <you@hanez.org>
 * Licensed under the terms of the Apache-2.0 license.
 * https://opensource.org/license/apache-2-0
 */

/* Regex full-match opcode using POSIX regex */
#ifdef __unix__
#include <regex.h>
#endif

case OP_REGEX_MATCH: {
 Value pattern = pop_value(vm);
 Value str = pop_value(vm);
 if (str.type != VAL_STRING || pattern.type != VAL_STRING) {
 fprintf(stderr, "Runtime type error: REGEX_MATCH expects (string, string)\n");
 exit(1);
 }
#ifndef __unix__
 /* Not supported on non-UNIX: return 0 gracefully */
 free_value(pattern);
 int truth = 0;
 free_value(str);
 push_value(vm, make_int(truth));
 break;
#else
 regex_t rx;
 int rc = regcomp(&rx, pattern.s ? pattern.s : "", REG_EXTENDED);
 if (rc != 0) {
 /* invalid regex -> false */
 free_value(pattern);
 free_value(str);
 push_value(vm, make_int(0));
 break;
 }
 regmatch_t m;
 int ok = regexec(&rx, str.s ? str.s : "", 1, &m, 0) == 0;
 int truth = 0;
 if (ok) {
 /* full match means the match spans whole string */
 if (m.rm_so == 0 && str.s) {
 size_t slen = strlen(str.s);
 truth = (m.rm_eo == (regoff_t)slen) ? 1 : 0;
 }
 }
 regfree(&rx);
 free_value(pattern);
 free_value(str);
 push_value(vm, make_int(truth));
 break;
#endif
}