95 lines
2.7 KiB
Python
95 lines
2.7 KiB
Python
|
#!/usr/bin/env python
|
||
|
|
# encoding: utf-8
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
def str2tokens(self, exp):
|
||
|
|
""" Parse the expression, ie tranform a string into a list of tokens
|
||
|
|
|
||
|
|
/!\ float are not availiable yet!
|
||
|
|
|
||
|
|
:param exp: The expression (a string)
|
||
|
|
:returns: list of token
|
||
|
|
|
||
|
|
"""
|
||
|
|
tokens = ['']
|
||
|
|
|
||
|
|
for character in exp:
|
||
|
|
if character.isdigit():
|
||
|
|
# for "big" numbers (like 2345)
|
||
|
|
if type(tokens[-1]) == int:
|
||
|
|
if tokens[-1] > 0:
|
||
|
|
tokens[-1] = tokens[-1]*10 + int(character)
|
||
|
|
else:
|
||
|
|
tokens[-1] = tokens[-1]*10 - int(character)
|
||
|
|
|
||
|
|
|
||
|
|
# Special case for "-" at the begining of an expression or before "("
|
||
|
|
elif tokens[-1] == "-" and \
|
||
|
|
str(tokens[-2]) in " (+-*/:":
|
||
|
|
tokens[-1] = - int(character)
|
||
|
|
else:
|
||
|
|
tokens.append(int(character))
|
||
|
|
|
||
|
|
elif character in "+-*/):^":
|
||
|
|
tokens.append(character)
|
||
|
|
|
||
|
|
elif character in "(":
|
||
|
|
# If "3(", ")("
|
||
|
|
if self.isNumber(tokens[-1]) \
|
||
|
|
or tokens[-1] == ")" :
|
||
|
|
tokens.append("*")
|
||
|
|
tokens.append(character)
|
||
|
|
|
||
|
|
elif character == ".":
|
||
|
|
raise ValueError("No float number please")
|
||
|
|
|
||
|
|
elif character != " ":
|
||
|
|
raise ValueError("{} is an unvalid character".format(character))
|
||
|
|
|
||
|
|
return tokens[1:]
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
def in2post_fix(cls, infix_tokens):
|
||
|
|
""" From the infix_tokens list compute the corresponding postfix_tokens list
|
||
|
|
|
||
|
|
@param infix_tokens: the infix list of tokens to transform into postfix form.
|
||
|
|
@return: the corresponding postfix list of tokens.
|
||
|
|
|
||
|
|
>>> .in2post_fix(['(', 2, '+', 5, '-', 1, ')', '/', '(', 3, '*', 4, ')'])
|
||
|
|
[2, 5, '+', 1, '-', 3, 4, '*', '/']
|
||
|
|
"""
|
||
|
|
opStack = Stack()
|
||
|
|
postfixList = []
|
||
|
|
|
||
|
|
for token in infix_tokens:
|
||
|
|
if token == "(":
|
||
|
|
opStack.push(token)
|
||
|
|
elif token == ")":
|
||
|
|
topToken = opStack.pop()
|
||
|
|
while topToken != "(":
|
||
|
|
postfixList.append(topToken)
|
||
|
|
topToken = opStack.pop()
|
||
|
|
elif cls.isOperator(token):
|
||
|
|
# On doit ajouter la condition == str sinon python ne veut pas tester l'appartenance à la chaine de caractère.
|
||
|
|
while (not opStack.isEmpty()) and (cls.PRIORITY[opStack.peek()] >= cls.PRIORITY[token]):
|
||
|
|
postfixList.append(opStack.pop())
|
||
|
|
opStack.push(token)
|
||
|
|
else:
|
||
|
|
postfixList.append(token)
|
||
|
|
|
||
|
|
while not opStack.isEmpty():
|
||
|
|
postfixList.append(opStack.pop())
|
||
|
|
|
||
|
|
return postfixList
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
# -----------------------------
|
||
|
|
# Reglages pour 'vim'
|
||
|
|
# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
|
||
|
|
# cursor: 16 del
|