str2tokens seems to works
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@ -8,7 +8,8 @@ class Operator(str):
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"""The operator class, is a string (representation of the operator) with its arity"""
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OPERATORS = { \
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PRIORITY = {"^": 5, "/": 4, "*" : 3, ":": 3, "+": 2, "-":2, "(": 1}
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OPERATIONS = { \
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"+": ["", "", ("__add__","__radd__")],\
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"-": ["", "__neg__", ("__sub__", "__rsub__")], \
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"*": ["", "", ("__mul__", "__rmul__")], \
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@ -20,7 +21,10 @@ class Operator(str):
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op = str.__new__(cls, operator)
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op.arity = arity
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op.actions = cls.OPERATORS[operator][arity]
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# TODO: Add op.visibility |sam. nov. 8 17:00:08 CET 2014
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op.priority = cls.PRIORITY[operator]
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op.actions = cls.OPERATIONS[operator][arity]
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return op
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@ -1,9 +1,24 @@
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#!/usr/bin/env python
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# encoding: utf-8
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from .operator import Operator
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from .generic import Stack
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def str2tokens(exp):
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""" Parse the string into tokens then turn it into postfix form
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>>> str2tokens('2+3*4')
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[2, 3, 4, '*', '+']
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>>> str2tokens('2*3+4')
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[2, 3, '*', 4, '+']
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"""
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in_tokens = str2in_tokens(exp)
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post_tokens = in2post_fix(in_tokens)
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def str2tokens(self, exp):
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return post_tokens
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def str2in_tokens(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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@ -11,6 +26,10 @@ def str2tokens(self, exp):
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:param exp: The expression (a string)
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:returns: list of token
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>>> str2tokens('2+3*4')
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['2', '+', '3', '*', '4']
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>>> str2tokens('2*3+4')
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['2', '*', '3', '+', '4']
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"""
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tokens = ['']
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@ -32,13 +51,14 @@ def str2tokens(self, exp):
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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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tokens.append(Operator(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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if isNumber(tokens[-1]) \
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or tokens[-1] == ")" :
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tokens.append("*")
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#tokens.append(Operator("*"))
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tokens.append(Operator("*"))
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tokens.append(character)
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elif character == ".":
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@ -51,41 +71,108 @@ def str2tokens(self, exp):
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def in2post_fix(cls, infix_tokens):
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def in2post_fix(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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>>> a, s, m, d, p = Operator("+"), Operator("-"), Operator("*"), Operator("/"), Operator("^")
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for token in infix_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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>>> in2post_fix(['-', '(', '-', 2, ')'])
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[2, '-', '-']
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>>> in2post_fix(['-', '(', '-', 2, '+', 3, '*', 4, ')'])
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[2, '-', 3, 4, '*', '+', '-']
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"""
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# Stack where operator will be stocked
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opStack = Stack()
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# final postfix list of tokens
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postfix_tokens = []
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# stack with the nbr of tokens still to compute in postfix_tokens
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arity_Stack = Stack()
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arity_Stack.push(0)
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for (pos_token,token) in enumerate(infix_tokens):
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## Pour voir ce qu'il se passe dans cette procédure
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#print(str(postfix_tokens), " | ", str(opStack), " | ", str(infix_tokens[(pos_token+1):]), " | ", str(arity_Stack))
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if token == "(":
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opStack.push(token)
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# Set next arity counter
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arity_Stack.push(0)
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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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op = opStack.pop()
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while op != "(":
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postfix_tokens.append(op)
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op = opStack.pop()
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# Go back to old arity
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arity_Stack.pop()
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# Raise the arity
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arity = arity_Stack.pop()
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arity_Stack.push(arity + 1)
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elif isOperator(token):
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while (not opStack.isEmpty()) and (opStack.peek().priority >= token.priority):
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op = opStack.pop()
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postfix_tokens.append(op)
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arity = arity_Stack.pop()
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token.arity = arity + 1
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opStack.push(token)
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# print("--", token, " -> ", str(arity + 1))
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# Reset arity to 0 in case there is other operators (the real operation would be "-op.arity + 1")
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arity_Stack.push(0)
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else:
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postfixList.append(token)
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postfix_tokens.append(token)
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arity = arity_Stack.pop()
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arity_Stack.push(arity + 1)
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while not opStack.isEmpty():
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postfixList.append(opStack.pop())
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op = opStack.pop()
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postfix_tokens.append(op)
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return postfixList
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# # Pour voir ce qu'il se passe dans cette procédure
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# print(str(postfix_tokens), " | ", str(opStack), " | ", str(infix_tokens[(pos_token+1):]), " | ", str(arity_Stack))
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if arity_Stack.peek() != 1:
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raise ValueError("Unvalid expression. The arity Stack is ", str(arity_Stack))
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return postfix_tokens
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def isOperator(exp):
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"""Check if the expression is an opération in "+-*/:^"
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:param exp: an expression
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:returns: boolean
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"""
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return type(exp) == Operator
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#return (type(exp) == str and exp in "+-*/:^")
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def isNumber(exp):
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"""Check if the expression can be a number
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:param exp: an expression
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:returns: True if the expression can be a number and false otherwise
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"""
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return type(exp) == int
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if __name__ == '__main__':
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#a, s, m, d, p = Operator("+"), Operator("-"), Operator("*"), Operator("/"), Operator("^")
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#in_tokens = str2in_tokens("2+3*4")
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#print("\t in_tokens :" + str(in_tokens))
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#
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#print(in2post_fix(in_tokens))
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import doctest
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doctest.testmod()
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# -----------------------------
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42
test/test_str2tokens.py
Normal file
42
test/test_str2tokens.py
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@ -0,0 +1,42 @@
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#!/usr/bin/env python
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# encoding: utf-8
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import unittest
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from pymath.str2tokens import str2tokens, str2in_tokens, in2post_fix
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class TestStr2tokens(unittest.TestCase):
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"""Testing functions from pymath.str2tokens"""
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def test_str2intokens(self):
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ans = str2in_tokens("2+3*4")
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self.assertEqual(ans, [2, "+", 3, "*", 4])
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ans = str2in_tokens("2*3+4")
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self.assertEqual(ans, [2, "*", 3, "+", 4])
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def test_in2post_fix(self):
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in_tokens = str2in_tokens("2+3*4")
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ans = in2post_fix(in_tokens)
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self.assertEqual(ans, [2, 3, 4, "*", "+"])
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in_tokens = str2in_tokens("2*3+4")
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ans = in2post_fix(in_tokens)
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self.assertEqual(ans, [2, 3,"*", 4, "+"])
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# TODO: Ajouter des tests pour les cas particuliers... |sam. nov. 8 17:39:18 CET 2014
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if __name__ == '__main__':
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unittest.main()
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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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