fun.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
 */


#include "bytecode.h"
#include "parser.h"
#include "vm.h"
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef FUN_WITH_REPL
#include "repl.h"
#endif

#ifndef FUN_VERSION
#define FUN_VERSION "0.0.0-dev"
#endif

static void print_usage(const char *prog) {
 printf("Fun %s\n", FUN_VERSION);
 printf("Usage:\n");
#ifdef FUN_WITH_REPL
 printf(" %s [--trace|-t] [--repl-on-error] [script.fun]\n", prog ? prog : "fun");
 printf(" %s --help | -h\n", prog ? prog : "fun");
 printf(" %s --version | -V\n", prog ? prog : "fun");
 printf("\n");
 printf("Options:\n");
 printf(" --trace, -t Print executed ops and stack tops during run\n");
 printf(" --repl-on-error Enter interactive REPL on runtime error with stack preserved\n\n");
 printf("When no script is provided, a REPL starts. Submit an empty line to execute the buffer.\n");
#else
 printf(" %s [--trace|-t] <script.fun>\n", prog ? prog : "fun");
 printf(" %s --help | -h\n", prog ? prog : "fun");
 printf(" %s --version | -V\n", prog ? prog : "fun");
 printf("\n");
 printf("Options:\n --trace, -t Print executed ops and stack tops during run\n\n");
 printf("REPL is disabled in this build. Please provide a script file to run.\n");
#endif
}

int main(int argc, char **argv) {
 /* Set FUN_EXECUTABLE environment variable to the path of this binary */
 setenv("FUN_EXECUTABLE", argv[0], 1);

 VM vm;
 vm_init(&vm);

 int argi = 1;
 for (; argi < argc; ++argi) {
 const char *arg = argv[argi];
 if (strcmp(arg, "--help") == 0 || strcmp(arg, "-h") == 0) {
 print_usage(argv[0]);
 return 0;
 }
 if (strcmp(arg, "--version") == 0 || strcmp(arg, "-V") == 0) {
 printf("Fun %s\n", FUN_VERSION);
 return 0;
 }
 if (strcmp(arg, "--trace") == 0 || strcmp(arg, "-t") == 0) {
 vm.trace_enabled = 1;
 continue;
 }
#ifdef FUN_WITH_REPL
 if (strcmp(arg, "--repl-on-error") == 0) {
 vm.repl_on_error = 1;
 vm.on_error_repl = fun_run_repl; /* provide REPL entry to core VM */
 continue;
 }
#endif
 /* first non-option assumed to be script path */
 break;
 }

#ifndef FUN_WITH_REPL
 if (argi >= argc) {
 fprintf(stderr, "Error: REPL is disabled. Please provide a script to run.\n");
 print_usage(argv[0]);
 return 2;
 }
#endif

 if (argi < argc) {
 const char *path = argv[argi];

 /* Collect script arguments (everything after script path) and expose via env vars */
 int sargi = argi + 1; /* first script arg following the script path */
 int sargc = (sargi < argc) ? (argc - sargi) : 0;

 /* Export FUN_ARGC */
 {
 char buf[32];
 snprintf(buf, sizeof(buf), "%d", sargc);
 setenv("FUN_ARGC", buf, 1);
 }

 /* Export FUN_ARGV_i */
 for (int i = 0; i < sargc; ++i) {
 char key[32];
 snprintf(key, sizeof(key), "FUN_ARGV_%d", i);
 setenv(key, argv[sargi + i], 1);
 }

 /* Optional: space-joined convenience string FUN_ARGS */
 if (sargc > 0) {
 size_t total = 0;
 for (int i = 0; i < sargc; ++i) {
 total += strlen(argv[sargi + i]) + 1; /* +1 for space or NUL */
 }
 char *joined = (char *)malloc(total);
 if (joined) {
 joined[0] = '\0';
 for (int i = 0; i < sargc; ++i) {
 strcat(joined, argv[sargi + i]);
 if (i + 1 < sargc) strcat(joined, " ");
 }
 setenv("FUN_ARGS", joined, 1);
 free(joined);
 }
 } else {
 /* Ensure FUN_ARGS is at least cleared for consistency */
 setenv("FUN_ARGS", "", 1);
 }

 Bytecode *bc = parse_file_to_bytecode(path);
 if (!bc) {
 fprintf(stderr, "Failed to compile script: %s\n", path);
 return 1;
 }

 vm_run(&vm, bc);
 vm_print_output(&vm);
 vm_clear_output(&vm);
 bytecode_free(bc);
 return vm.exit_code;
 }

#ifdef FUN_WITH_REPL
 return fun_run_repl(&vm);
#else
 fprintf(stderr, "Internal error: REPL not available in this build.\n");
 return 2;
#endif
}