pop.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 pop.c
 * @brief Implements the OP_POP opcode for removing the top stack value in the VM.
 *
 * This file handles the OP_POP instruction, which removes the top value from the stack.
 *
 * Behavior:
 * - Removes the top value from the stack.
 *
 * Error Handling:
 * - Exits with an error if the stack is empty.
 *
 * Example:
 * - Bytecode: OP_POP
 * - Stack before: [42]
 * - Stack after: []
 */
 
case OP_POP: {
  if (vm->sp < 0) {
    fprintf(stderr, "Runtime error: stack underflow for POP\n");
    exit(1);
  }
  Value v = pop_value(vm);
  free_value(v);
  break;
}