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Start spliting exp

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lafrite 2014-11-08 16:43:04 +01:00
parent eb1088d31f
commit 825e861366
2 changed files with 121 additions and 109 deletions
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136
pymath/expression.py
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@ -108,88 +108,39 @@ class Expression(object):
self.child = Expression(steps[-1]) self.child = Expression(steps[-1])
## --------------------- ## ---------------------
## String parsing ## "fix" recognition
@classmethod #@classmethod
def str2tokens(self, exp): #def get_fix(self, tokens):
""" Parse the expression, ie tranform a string into a list of tokens # """ Give the "fix" of an expression
# [A, +, B] -> infix, or if there is parenthesis it is infix
# [+, A, B] -> prefix
# [A, B, +] -> postfix
# /!\ does not verify if the expression is correct/computable!
/!\ float are not availiable yet! # :param exp: the expression (list of token)
# :returns: the "fix" (infix, postfix, prefix)
:param exp: The expression (a string) # """
:returns: list of token # if self.isOperator(tokens[0]):
# return "prefix"
# elif "(" in tokens:
# return "infix"
# elif not self.isOperator(tokens[0]) and not self.isOperator(tokens[1]):
# return "postfix"
# else:
# return "infix"
""" #def feed_fix(self):
tokens = [''] # """ Recognize the fix of self.tokens and stock tokens in self.[fix]_tokens """
# if len(self.tokens) > 1:
# fix = self.get_fix(self.tokens)
# else:
# fix = "postfix" # Completement arbitraire mais on s'en fiche!
for character in exp: # setattr(self, fix+"_tokens", self.tokens)
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:]
# ---------------------
# "fix" recognition
@classmethod
def get_fix(self, tokens):
""" Give the "fix" of an expression
[A, +, B] -> infix, or if there is parenthesis it is infix
[+, A, B] -> prefix
[A, B, +] -> postfix
/!\ does not verify if the expression is correct/computable!
:param exp: the expression (list of token)
:returns: the "fix" (infix, postfix, prefix)
"""
if self.isOperator(tokens[0]):
return "prefix"
elif "(" in tokens:
return "infix"
elif not self.isOperator(tokens[0]) and not self.isOperator(tokens[1]):
return "postfix"
else:
return "infix"
def feed_fix(self):
""" Recognize the fix of self.tokens and stock tokens in self.[fix]_tokens """
if len(self.tokens) > 1:
fix = self.get_fix(self.tokens)
else:
fix = "postfix" # Completement arbitraire mais on s'en fiche!
setattr(self, fix+"_tokens", self.tokens)
# ---------------------- # ----------------------
@ -239,39 +190,6 @@ class Expression(object):
# "fix" tranformations # "fix" tranformations
@classmethod @classmethod
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.
>>> Expression.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
## --------------------- ## ---------------------
## Computing the expression ## Computing the expression

94
pymath/str2tokens.py Normal file
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@ -0,0 +1,94 @@
#!/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