def term(tk):
s1 = factor(tk)
token_num, token_value = current().token_num, current().token_value
value = s1
while token_value == "*" or token_value == "/":
next(tk)
s2 = term(tk)
if token_value == "*":
value = BinaryOpNode(2, value, s2)
else:
value = BinaryOpNode(3, value, s2)
token_num, token_value = current().token_num, current().token_value
return value
def expr(tk):
s1 = term(tk)
token_num, token_value = current().token_num, current().token_value
value = s1
while token_value == "+" or token_value == "-":
next(tk)
s2 = term(tk)
if token_value == "+":
value = BinaryOpNode(0, value, s2)
else:
value = BinaryOpNode(1, value, s2)
token_num, token_value = current().token_num, current().token_value
return value
def term(tk):
s1 = factor(tk)
token_num, token_value = current().token_num, current().token_value
value = s1
while token_value == "*" or token_value == "/":
next(tk)
s2 = term(tk)
if token_value == "*":
value = MulNode(value, s2)
else:
value = DivNode(value, s2)
token_num, token_value = current().token_num, current().token_value
return value
def expr(tk):
s1 = term(tk)
token_num, token_value = current().token_num, current().token_value
value = s1
while token_value == "+" or token_value == "-":
next(tk)
s2 = term(tk)
if token_value == "+":
value = AddNode(value, s2)
else:
value = SubNode(value, s2)
token_num, token_value = current().token_num, current().token_value
return value
def factor(tk):
if current().token_num == tokenize.NUMBER:
value = current().token_value
next(tk)
return ConstNode(int(value))
elif current().token_value == "(":
next(tk)
f = expr(tk)
if current().token_value != ")":
print("parse error! value = %s" % current().token_value)
value = f
next(tk)
return value
value = BinaryOpNode(2, value, s2)
else:
value = BinaryOpNode(3, value, s2)
token_num, token_value = current().token_num, current().token_value
return value
def factor(tk):
if current().token_num == tokenize.NUMBER:
value = current().token_value
next(tk)
return ConstNode(int(value))
elif current().token_value == "(":
next(tk)
f = expr(tk)
if current().token_value != ")":
print("parse error! value = %s" % current().token_value)
value = f
next(tk)
return value
if __name__ == '__main__':
with open(sys.argv[1], "r") as f:
tk = tokenize.generate_tokens(f.readline)
next(tk)
vs = Visitor()
AST = expr(tk)
print("FINAL VALUE %d" % vs.visit(AST))