join.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 join.c
 * @brief Implements the OP_JOIN opcode for joining array elements into a string in the VM.
 *
 * This file handles the OP_JOIN instruction, which joins the elements of an array into a string
 * using a separator. The separator and array are popped from the stack, and the resulting string
 * is pushed back.
 *
 * Behavior:
 * - Pops the separator and array from the stack.
 * - Joins the array elements into a string using the separator.
 * - Pushes the resulting string onto the stack.
 *
 * Error Handling:
 * - Exits with an error if the array or separator is of the wrong type.
 *
 * Example:
 * - Bytecode: OP_JOIN
 * - Stack before: [", ", ["a", "b", "c"]]
 * - Stack after: ["a, b, c"]
 */
 
case OP_JOIN: {
  Value sep = pop_value(vm);
  Value arr = pop_value(vm);
  if (arr.type != VAL_ARRAY || sep.type != VAL_STRING) {
    fprintf(stderr, "Runtime type error: JOIN expects (array, string)\n");
    exit(1);
  }
  Value out = bi_join(&arr, &sep);
  free_value(arr);
  free_value(sep);
  push_value(vm, out);
  break;
}