write_file.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
 */
 
/**
 * @file write_file.c
 * @brief Implements the OP_WRITE_FILE opcode for writing to a file in the VM.
 *
 * This file handles the OP_WRITE_FILE instruction, which writes data to a file.
 * The file path and data are popped from the stack, and a success/failure flag is pushed back.
 *
 * Behavior:
 * - Pops the file path and data from the stack.
 * - Writes the data to the file.
 * - Pushes 1 (success) or 0 (failure) onto the stack.
 *
 * Error Handling:
 * - Exits with an error if the file path is invalid or the file cannot be written.
 *
 * Example:
 * - Bytecode: OP_WRITE_FILE
 * - Stack before: ["file.txt", "data"]
 * - Stack after: [1]
 */
 
case OP_WRITE_FILE: {
  Value data = pop_value(vm);
  Value path = pop_value(vm);
  if (path.type != VAL_STRING || data.type != VAL_STRING) {
    fprintf(stderr, "WRITE_FILE expects (string, string)\n");
    exit(1);
  }
  const char *p = path.s ? path.s : "";
  FILE *f = fopen(p, "wb");
  int ok = 0;
  if (f) {
    size_t len = data.s ? strlen(data.s) : 0;
    ok = (fwrite(data.s ? data.s : "", 1, len, f) == len);
    fclose(f);
  }
  free_value(path);
  free_value(data);
  push_value(vm, make_int(ok ? 1 : 0));
  break;
}