jump_if_false.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 jump_if_false.c
 * @brief Implements the OP_JUMP_IF_FALSE opcode for conditional jumps in the VM.
 *
 * This file handles the OP_JUMP_IF_FALSE instruction, which jumps if the top
 * stack value is falsey (0, false, nil, etc).
 *
 * Behavior:
 * - Pops condition value from stack
 * - Jumps to operand IP if falsey
 * - Continues normally if truthy
 *
 * Used for:
 * - If statements
 * - While loops
 * - Logical expressions
 */
 
case OP_JUMP_IF_FALSE: {
  Value cond = pop_value(vm);
  int truthy = value_is_truthy(&cond);
  free_value(cond);
  if (!truthy) {
    f->ip = inst.operand;
  }
  break;
}