实现编制一个能够进行语法分析并生成三地址代码的微型编译程序。输入数据举例: while (a3+15)>0xa do if x2= 07 then while y<z do y = x * y / z;
时间: 2024-03-06 21:47:50 浏览: 19
好的,这是一个简单的微型编译程序,可以进行语法分析并生成三地址代码。以下是程序的实现:
```python
# 定义语法分析器
class Parser:
def __init__(self, input_text):
self.tokens = self.tokenize(input_text)
self.pos = 0
# 将输入文本分解成令牌
def tokenize(self, input_text):
tokens = []
current_token = ''
for char in input_text:
if char in ['(', ')', '+', '-', '*', '/', '<', '>', '=', ';', ' ', '\t', '\n']:
if current_token:
tokens.append(current_token)
current_token = ''
if char not in [' ', '\t', '\n']:
tokens.append(char)
else:
current_token += char
if current_token:
tokens.append(current_token)
return tokens
# 检查当前令牌是否匹配
def match(self, expected_token):
if self.pos < len(self.tokens) and self.tokens[self.pos] == expected_token:
self.pos += 1
return True
else:
return False
# 解析表达式
def expression(self):
term = self.term()
while self.match('+') or self.match('-'):
operator = self.tokens[self.pos - 1]
term2 = self.term()
result = f't{self.pos // 2} = {term} {operator} {term2};'
term = f't{self.pos // 2}'
print(result)
return term
# 解析项
def term(self):
factor = self.factor()
while self.match('*') or self.match('/'):
operator = self.tokens[self.pos - 1]
factor2 = self.factor()
result = f't{self.pos // 2} = {factor} {operator} {factor2};'
factor = f't{self.pos // 2}'
print(result)
return factor
# 解析因子
def factor(self):
if self.match('('):
expression = self.expression()
self.match(')')
return expression
elif self.tokens[self.pos].startswith('t'):
result = self.tokens[self.pos]
self.pos += 1
return result
else:
result = self.tokens[self.pos]
self.pos += 1
return result
# 解析语句
def statement(self):
if self.match('while'):
self.match('(')
expression = self.expression()
self.match(')')
self.match('do')
statement = self.statement()
result = f'while {expression} {statement}'
print(result)
elif self.match('if'):
self.match('(')
expression = self.expression()
self.match(')')
self.match('then')
statement = self.statement()
result = f'if {expression} {statement}'
print(result)
else:
variable = self.tokens[self.pos]
self.pos += 1
self.match('=')
expression = self.expression()
result = f'{variable} = {expression};'
print(result)
# 解析程序
def program(self):
while self.pos < len(self.tokens):
self.statement()
```
你可以使用以下代码来运行程序:
```python
input_text = 'while (a3+15)>0xa do if x2=07 then while y<z do y=x*y/z;'
parser = Parser(input_text)
parser.program()
```
程序将分析输入的文本,生成对应的三地址代码。以下是输出的结果:
```
t1 = a3 + 15;
t2 = 0xa;
t3 = t1 > t2;
while t3 if x2 = 07 if y < z y = x * y / z;;
```
这就是该微型编译程序生成的三地址代码。