1.实现变量相加的简易版
what_to_execute={
"instructions":[("LOAD_VALUE",0),
("STORE_NAME",0),
("LOAD_VALUE",1),
("STORE_NAME",1),
("LOAD_NAME",0),
("LOAD_NAME",1),
("ADD_TWO_VALUES",None),
("PRINT_ANSWER",None)],
#instruction代表指令,0与1代表其在number中的key
"numbers":[12,8],
"names":['a','b']
}
#()为元组，[]为列表，{}为字典，元组的特点是不可修改
class Interpreter:
def __init__(self):
self.stack=[]
self.enviorment={}#存储变量与变量指向的值
def LOAD_VALUE(self,number):
self.stack.append(number)
def PRINT_ANSWER(self):
answer=self.stack.pop()
print(answer)
def ADD_TWO_VALUES(self):
first_num=self.stack.pop()
second_num=self.stack.pop()
total=first_num+second_num
self.stack.append(total)
def STORE_NAME(self,name):
val=self.stack.pop()
self.enviorment[name]=val
def LOAD_NAME(self,name):
val=self.enviorment[name]
self.stack.append(val)#即将变量的值取出放入stack中
def parse_argument(self,instruction,argument,what_to_execute):
#解析命令参数
numbers=["LOAD_VALUE"]#使用常量列表
names=["LOAD_NAME","STORE_NAME"]
if instruction in numbers:
argument=what_to_execute["numbers"][argument]
elif instruction in names:
argument=what_to_execute["names"][argument]
return argument
def execute(self,what_to_execute):
instructions = what_to_execute["instructions"]
for each_step in instructions:
instruction, argument = each_step
argument = self.parse_argument(instruction, argument, what_to_execute)
bytecode_method = getattr(self, instruction)
if argument is None:
bytecode_method()
else:
bytecode_method(argument)
'''
if instruction=='LOAD_VALUE':
self.LOAD_VALUE(argument)
elif instruction=='PRINT_ANSWER':
self.PRINT_ANSWER()
elif instruction=='ADD_TWO_VALUES':
self.ADD_TWO_VALUES()
elif instruction=='STORE_NAME':
self.STORE_NAME(argument)
elif instruction=='LOAD_NAME':
self.LOAD_NAME(argument)
'''
test=Interpreter()
test.execute(what_to_execute)
