102 lines
2.5 KiB
Python
102 lines
2.5 KiB
Python
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#!/usr/bin/env python
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# encoding: utf-8
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class Expression(object):
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"""A calculus expression. Today it can andle only expression with numbers later it will be able to manipulate unknown"""
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def __init__(self, exp):
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""" Initiate the expression.
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:param exp: the expression. It can be a string or a list of tokens. It can be infix or postfix expression
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"""
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pass
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# ---------------------
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# String parsing
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# @classmethod ????
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def parseExp(self, exp):
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""" Parse the expression, ie tranform a string into a list of tokens
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:param exp: The expression
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:returns: list of token
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"""
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pass
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# ---------------------
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# "fix" recognition
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def expressionFix(self, exp):
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""" Give the "fix" of an expression
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infix -> A + B
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prefix -> + A B
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postfix -> A B +
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:param exp: the expression
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:returns: the "fix" (infix, postfix, prefix)
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"""
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pass
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# ----------------------
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# "fix" tranformations
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def toPostfix(self):
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""" Transorm the expression into postfix form """
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pass
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def toInfix(self):
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""" Tranform the expression into infix form"""
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pass
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# ---------------------
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# Tools for placing parenthesis in infix notation
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def needPar(operande, operator, posi = "after"):
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""" Says whether or not the operande needs parenthesis
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:param operande: the operande
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:param operator: the operator
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:param posi: "after"(default) if the operande will be after the operator, "before" othewise
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:returns: bollean
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"""
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pass
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def get_main_op(exp):
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""" Gives the main operation of the expression
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:param exp: the expression
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:returns: the main operation (+, -, * or /) or 0 if the expression is only one element
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"""
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pass
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# ---------------------
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# Computing the expression
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def compute(self):
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""" Recursive method for computing as a student the expression
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:returns: list of steps needed to reach the result
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"""
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pass
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def doMath(op, op1, op2):
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"""Compute "op1 op op2"
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:param op: operator
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:param op1: first operande
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:param op2: second operande
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:returns: string representing the result
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"""
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return str(eval(op1 + op + op2))
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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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