Start spliting exp
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lafrite
parent
eb1088d31f
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825e861366
@ -108,88 +108,39 @@ class Expression(object):
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self.child = Expression(steps[-1])
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## ---------------------
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## String parsing
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## "fix" recognition
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@classmethod
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def str2tokens(self, exp):
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""" Parse the expression, ie tranform a string into a list of tokens
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#@classmethod
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#def get_fix(self, tokens):
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# """ Give the "fix" of an expression
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# [A, +, B] -> infix, or if there is parenthesis it is infix
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# [+, A, B] -> prefix
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# [A, B, +] -> postfix
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# /!\ does not verify if the expression is correct/computable!
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/!\ float are not availiable yet!
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# :param exp: the expression (list of token)
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# :returns: the "fix" (infix, postfix, prefix)
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:param exp: The expression (a string)
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:returns: list of token
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# """
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# if self.isOperator(tokens[0]):
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# return "prefix"
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# elif "(" in tokens:
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# return "infix"
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# elif not self.isOperator(tokens[0]) and not self.isOperator(tokens[1]):
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# return "postfix"
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# else:
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# return "infix"
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"""
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tokens = ['']
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#def feed_fix(self):
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# """ Recognize the fix of self.tokens and stock tokens in self.[fix]_tokens """
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# if len(self.tokens) > 1:
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# fix = self.get_fix(self.tokens)
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# else:
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# fix = "postfix" # Completement arbitraire mais on s'en fiche!
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for character in exp:
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if character.isdigit():
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# for "big" numbers (like 2345)
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if type(tokens[-1]) == int:
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if tokens[-1] > 0:
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tokens[-1] = tokens[-1]*10 + int(character)
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else:
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tokens[-1] = tokens[-1]*10 - int(character)
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# Special case for "-" at the begining of an expression or before "("
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elif tokens[-1] == "-" and \
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str(tokens[-2]) in " (+-*/:":
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tokens[-1] = - int(character)
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else:
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tokens.append(int(character))
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elif character in "+-*/):^":
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tokens.append(character)
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elif character in "(":
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# If "3(", ")("
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if self.isNumber(tokens[-1]) \
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or tokens[-1] == ")" :
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tokens.append("*")
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tokens.append(character)
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elif character == ".":
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raise ValueError("No float number please")
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elif character != " ":
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raise ValueError("{} is an unvalid character".format(character))
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return tokens[1:]
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# ---------------------
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# "fix" recognition
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@classmethod
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def get_fix(self, tokens):
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""" Give the "fix" of an expression
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[A, +, B] -> infix, or if there is parenthesis it is infix
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[+, A, B] -> prefix
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[A, B, +] -> postfix
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/!\ does not verify if the expression is correct/computable!
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:param exp: the expression (list of token)
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:returns: the "fix" (infix, postfix, prefix)
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"""
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if self.isOperator(tokens[0]):
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return "prefix"
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elif "(" in tokens:
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return "infix"
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elif not self.isOperator(tokens[0]) and not self.isOperator(tokens[1]):
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return "postfix"
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else:
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return "infix"
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def feed_fix(self):
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""" Recognize the fix of self.tokens and stock tokens in self.[fix]_tokens """
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if len(self.tokens) > 1:
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fix = self.get_fix(self.tokens)
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else:
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fix = "postfix" # Completement arbitraire mais on s'en fiche!
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setattr(self, fix+"_tokens", self.tokens)
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# setattr(self, fix+"_tokens", self.tokens)
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# ----------------------
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@ -239,39 +190,6 @@ class Expression(object):
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# "fix" tranformations
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@classmethod
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def in2post_fix(cls, infix_tokens):
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""" From the infix_tokens list compute the corresponding postfix_tokens list
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@param infix_tokens: the infix list of tokens to transform into postfix form.
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@return: the corresponding postfix list of tokens.
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>>> Expression.in2post_fix(['(', 2, '+', 5, '-', 1, ')', '/', '(', 3, '*', 4, ')'])
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[2, 5, '+', 1, '-', 3, 4, '*', '/']
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"""
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opStack = Stack()
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postfixList = []
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for token in infix_tokens:
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if token == "(":
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opStack.push(token)
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elif token == ")":
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topToken = opStack.pop()
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while topToken != "(":
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postfixList.append(topToken)
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topToken = opStack.pop()
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elif cls.isOperator(token):
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# On doit ajouter la condition == str sinon python ne veut pas tester l'appartenance à la chaine de caractère.
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while (not opStack.isEmpty()) and (cls.PRIORITY[opStack.peek()] >= cls.PRIORITY[token]):
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postfixList.append(opStack.pop())
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opStack.push(token)
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else:
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postfixList.append(token)
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while not opStack.isEmpty():
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postfixList.append(opStack.pop())
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return postfixList
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## ---------------------
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## Computing the expression
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94
pymath/str2tokens.py
Normal file
94
pymath/str2tokens.py
Normal file
@ -0,0 +1,94 @@
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#!/usr/bin/env python
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# encoding: utf-8
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def str2tokens(self, exp):
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""" Parse the expression, ie tranform a string into a list of tokens
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/!\ float are not availiable yet!
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:param exp: The expression (a string)
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:returns: list of token
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"""
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tokens = ['']
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for character in exp:
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if character.isdigit():
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# for "big" numbers (like 2345)
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if type(tokens[-1]) == int:
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if tokens[-1] > 0:
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tokens[-1] = tokens[-1]*10 + int(character)
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else:
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tokens[-1] = tokens[-1]*10 - int(character)
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# Special case for "-" at the begining of an expression or before "("
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elif tokens[-1] == "-" and \
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str(tokens[-2]) in " (+-*/:":
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tokens[-1] = - int(character)
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else:
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tokens.append(int(character))
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elif character in "+-*/):^":
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tokens.append(character)
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elif character in "(":
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# If "3(", ")("
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if self.isNumber(tokens[-1]) \
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or tokens[-1] == ")" :
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tokens.append("*")
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tokens.append(character)
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elif character == ".":
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raise ValueError("No float number please")
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elif character != " ":
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raise ValueError("{} is an unvalid character".format(character))
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return tokens[1:]
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def in2post_fix(cls, infix_tokens):
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""" From the infix_tokens list compute the corresponding postfix_tokens list
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@param infix_tokens: the infix list of tokens to transform into postfix form.
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@return: the corresponding postfix list of tokens.
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>>> .in2post_fix(['(', 2, '+', 5, '-', 1, ')', '/', '(', 3, '*', 4, ')'])
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[2, 5, '+', 1, '-', 3, 4, '*', '/']
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"""
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opStack = Stack()
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postfixList = []
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for token in infix_tokens:
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if token == "(":
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opStack.push(token)
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elif token == ")":
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topToken = opStack.pop()
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while topToken != "(":
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postfixList.append(topToken)
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topToken = opStack.pop()
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elif cls.isOperator(token):
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# On doit ajouter la condition == str sinon python ne veut pas tester l'appartenance à la chaine de caractère.
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while (not opStack.isEmpty()) and (cls.PRIORITY[opStack.peek()] >= cls.PRIORITY[token]):
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postfixList.append(opStack.pop())
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opStack.push(token)
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else:
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postfixList.append(token)
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while not opStack.isEmpty():
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postfixList.append(opStack.pop())
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return postfixList
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# -----------------------------
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# Reglages pour 'vim'
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# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
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# cursor: 16 del
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