class SimpleVM:
    # 初始化方法
    def __init__(self):
        self.stack = []
        self.locals = {}
        self.globls = {}

    def load_const(self, const):
        # 将常量推到栈中
        self.stack.append(const)
        print(f"加载常量: {const} -> 栈: {self.stack}")

    def store_name(self, name):
        if not self.stack:
            raise RuntimeError("栈为空")
        # 取出值
        value = self.stack.pop()
        # 存储到字典中
        self.locals[name] = value
        print(f"存储变量: {name} = {value}")

    def load_name(self, name):
        if name in self.locals:
            value = self.locals[name]
        elif name in self.globls:
            value = self.globls[name]
        else:
            raise RecursionError(f"name:{name} is not defined")
        self.stack.append(value)
        print(f"加载变量: {name} = {value} -> 栈: {self.stack}")

    def binary_add(self):
        if len(self.stack) < 2:
            raise RecursionError("栈中元素不足")
        #
        a = self.stack.pop()
        b = self.stack.pop()
        result = a + b
        self.stack.append(result)
        print(f"加法: {a} + {b} = {result} -> 栈: {self.stack}")

    def return_value(self):
        if not self.stack:
            return None
        value = self.stack.pop()
        print(f"返回: {value}")
        return value


def vm_execution():
    vm = SimpleVM()
    # 输出即将执行的代码说明
    print("执行代码: a = 10; b = 20; c = a + b")
    # 构造指令序列
    instructions = [
        ("LOAD_CONST", 10),  # 加载常量10
        ("STORE_NAME", "a"),  # 存储到变量a
        ("LOAD_CONST", 20),  # 加载常量20
        ("STORE_NAME", "b"),  # 存储到变量b
        ("LOAD_NAME", "a"),  # 加载变量a
        ("LOAD_NAME", "b"),  # 加载变量b
        ("BINARY_ADD",),  # 执行加法
        ("STORE_NAME", "c"),  # 存储到变量c
        ("LOAD_NAME", "c"),  # 加载变量c
        ("RETURN_VALUE",),  # 返回值
    ]

    for instruction in instructions:
        # 获取操作嘛
        op = instruction[0]
        # 获取操作参数
        args = instruction[1:] if len(instruction) > 1 else []
        # 判断不同指令，来调用不同的方法
        if op == "LOAD_CONST":
            vm.load_const(args[0])
        elif op == "STORE_NAME":
            vm.store_name(args[0])
        elif op == "LOAD_NAME":
            vm.load_name(args[0])
        elif op == "BINARY_ADD":
            vm.binary_add()
        elif op == "RETURN_VALUE":
            result = vm.return_value()

    print(f"最终打印结果c={result}")


vm_execution()