396 lines
12 KiB
Python
396 lines
12 KiB
Python
#!/usr/bin/env python
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# encoding: utf-8
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from .generic import Stack, flatten_list, expand_list, isNumber, isOperator, isNumerand
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from .render import txt, tex
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from .str2tokens import str2tokens
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from .operator import op
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from .random_expression import RdExpression
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__all__ = ['Expression']
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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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STR_RENDER = tex
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DEFAULT_RENDER = tex
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@classmethod
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def set_render(cls, render):
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cls.STR_RENDER = render
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@classmethod
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def get_render(cls ):
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return cls.STR_RENDER
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@classmethod
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def set_default_render(cls):
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cls.set_render(cls.DEFAULT_RENDER)
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@classmethod
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def random(self, form="", conditions=[], val_min = -10, val_max=10):
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"""Create a random expression from form and with conditions
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:param form: the form of the expression (/!\ variables need to be in brackets {})
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:param conditions: condition on variables (/!\ variables need to be in brackets {})
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:param val_min: min value for generate variables
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:param val_max: max value for generate variables
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"""
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random_generator = RdExpression(form, conditions)
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return Expression(random_generator(val_min, val_max))
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def __new__(cls, exp):
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"""Create Expression objects
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:param exp: the expression. It can be a string or a list of postfix tokens.
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"""
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expression = object.__new__(cls)
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if type(exp) == str:
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#self._exp = exp
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expression.postfix_tokens = str2tokens(exp) # les tokens seront alors stockés dans self.tokens temporairement
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elif type(exp) == list:
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expression.postfix_tokens = flatten_list([tok.postfix_tokens if Expression.isExpression(tok) else tok for tok in exp])
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else:
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raise ValueError("Can't build Expression with {} object".format(type(exp)))
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if len(expression.postfix_tokens) == 1:
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token = expression.postfix_tokens[0]
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if hasattr(token, 'simplify'):
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return expression.postfix_tokens[0]
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elif type(token) == int:
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# On crée un faux int en ajoutant la méthode simplify et simplified et la caractérisique isNumber
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simplify = lambda x:[x]
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simplified = lambda x:x
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is_number = True
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methods_attr = {'simplify':simplify, 'simplified':simplified, 'isNumber': is_number}
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fake_token = type('fake_int', (int,), methods_attr)(token)
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return fake_token
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elif type(token) == str:
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# On crée un faux str en ajoutant la méthode simplify et simplified et la caractérisique isNumber
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simplify = lambda x:[x]
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simplified = lambda x:x
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is_polynom = True
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methods_attr = {'simplify':simplify, 'simplified':simplified, '_isPolynom': is_polynom}
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fake_token = type('fake_str', (str,), methods_attr)(token)
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return fake_token
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else:
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raise ValueError("Unknow type in Expression: {}".format(type(token)))
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else:
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expression._isExpression = 1
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return expression
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def __str__(self):
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"""
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Overload str
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If you want to changer render use Expression.set_render(...)
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"""
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return self.STR_RENDER(self.postfix_tokens)
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def __repr__(self):
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return "< Expression " + str(self.postfix_tokens) + ">"
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def render(self, render = lambda x:str(x)):
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""" Same as __str__ but accept render as argument
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:param render: function which render the list of token (postfix form) to string
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"""
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# TODO: I don't like the name of this method |ven. janv. 17 12:48:14 CET 2014
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return render(self.postfix_tokens)
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## ---------------------
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## Mechanism functions
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def simplify(self):
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""" Generator which return steps for computing the expression """
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if not self.can_go_further():
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yield self.STR_RENDER(self.postfix_tokens)
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else:
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self.compute_exp()
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old_s = ''
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for s in self.steps:
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new_s = self.STR_RENDER(s)
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# Astuce pour éviter d'avoir deux fois la même étape (par exemple pour la transfo d'une division en fraction)
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if new_s != old_s:
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old_s = new_s
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yield new_s
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if Expression.isExpression(self.child):
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for s in self.child.simplify():
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if old_s != s:
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old_s = s
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yield s
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else:
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for s in self.child.simplify():
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new_s = self.STR_RENDER([s])
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# Astuce pour éviter d'avoir deux fois la même étape (par exemple pour la transfo d'une division en fraction)
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if new_s != old_s:
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old_s = new_s
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yield new_s
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if old_s != str(self.child):
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yield self.STR_RENDER([self.child])
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def simplified(self):
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""" Get the simplified version of the expression """
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self.compute_exp()
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try:
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return self.child.simplified()
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except AttributeError:
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return self.child
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def can_go_further(self):
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"""Check whether it's a last step or not. If not create self.child the next expression.
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:returns: 1 if it's not the last step, 0 otherwise
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"""
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if len(self.postfix_tokens) == 1:
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return 0
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else:
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return 1
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def compute_exp(self):
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""" Create self.child with self.steps to go up to it """
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self.steps = [self.postfix_tokens]
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tokenList = self.postfix_tokens.copy()
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tmpTokenList = []
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while len(tokenList) > 2:
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# on va chercher les motifs du genre A B +, quand l'operateur est d'arité 2, pour les calculer
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if isNumerand(tokenList[0]) and isNumerand(tokenList[1]) \
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and isOperator(tokenList[2]) and tokenList[2].arity == 2 :
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# S'il y a une opération à faire
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op1 = tokenList[0]
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op2 = tokenList[1]
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operator = tokenList[2]
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res = operator(op1, op2)
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tmpTokenList.append(res)
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# Comme on vient de faire le calcul, on peut détruire aussi les deux prochains termes
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del tokenList[0:3]
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# Et les motifs du gens A -, quand l'operateur est d'arité 1
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elif isNumerand(tokenList[0]) \
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and isOperator(tokenList[1]) and tokenList[1].arity == 1:
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# S'il y a une opération à faire
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op1 = tokenList[0]
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operator = tokenList[1]
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res = operator(op1)
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tmpTokenList.append(res)
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# Comme on vient de faire le calcul, on peut détruire aussi les deux prochains termes
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del tokenList[0:2]
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else:
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tmpTokenList.append(tokenList[0])
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del tokenList[0]
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if len(tokenList) == 2 and isNumerand(tokenList[0]) \
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and isOperator(tokenList[1]) and tokenList[1].arity == 1:
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# S'il reste deux éléments dont un operation d'arité 1
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op1 = tokenList[0]
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operator = tokenList[1]
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res = operator(op1)
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tmpTokenList.append(res)
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# Comme on vient de faire le calcul, on peut détruire aussi les deux prochains termes
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del tokenList[0:2]
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tmpTokenList += tokenList
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steps = expand_list(tmpTokenList)
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if len(steps[:-1]) > 0:
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self.steps += [flatten_list(s) for s in steps[:-1]]
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self.child = Expression(steps[-1])
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@classmethod
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def isExpression(self, other):
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try:
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other._isExpression
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except AttributeError:
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return 0
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return 1
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# -----------
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# Expression act as container from self.postfix_tokens
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def __getitem__(self, index):
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return self.postfix_tokens[index]
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def __setitem__(self, index, value):
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self.postfix_tokens[index] = value
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# -----------
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# Some math manipulations
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def operate(self, other, operator):
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if type(other) == Expression:
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return Expression(self.postfix_tokens + other.postfix_tokens + [operator])
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elif type(other) == list:
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return Expression(self.postfix_tokens + other + [operator])
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else:
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return Expression(self.postfix_tokens + [other] + [operator])
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def roperate(self, other, operator):
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if type(other) == Expression:
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return Expression(other.postfix_tokens + self.postfix_tokens + [operator])
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elif type(other) == list:
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return Expression(other + self.postfix_tokens + [operator])
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else:
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return Expression([other] + self.postfix_tokens + [operator])
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def __add__(self, other):
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return self.operate(other, op.add)
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def __radd__(self, other):
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return self.roperate(other, op.add)
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def __sub__(self, other):
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return self.operate(other, op.sub)
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def __rsub__(self, other):
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return self.roperate(other, op.sub)
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def __mul__(self, other):
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return self.operate(other, op.mul)
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def __rmul__(self, other):
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return self.roperate(other, op.mul)
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def __div__(self, other):
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return self.operate(other, op.div)
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def __rdiv__(self, other):
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return self.roperate(other, op.div)
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def __pow__(self, other):
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return self.operate(other, op.pow)
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def __neg__(self):
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return Expression(self.postfix_tokens + [op.sub1])
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def test(exp):
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a = Expression(exp)
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print(a)
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for i in a.simplify():
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print(type(i))
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print(i)
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#print(type(a.simplified()), ":", a.simplified())
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print("\n")
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if __name__ == '__main__':
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render = lambda _,x : str(x)
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Expression.set_render(render)
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exp = Expression("1/2 - 4")
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print(list(exp.simplify()))
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#Expression.set_render(txt)
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#exp = "2 ^ 3 * 5"
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#test(exp)
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#exp = "2x + 5"
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#test(exp)
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#Expression.set_render(tex)
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#test(exp1)
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#from pymath.operator import op
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#exp = [2, 3, op.pw, 5, op.mul]
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#test(exp)
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#test([Expression(exp1), Expression(exp), op.add])
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#exp = "1 + 3 * 5"
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#e = Expression(exp)
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#f = -e
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#print(f)
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#exp = "2 * 3 * 3 * 5"
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#test(exp)
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#exp = "2 * 3 + 3 * 5"
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#test(exp)
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#exp = "2 * ( 3 + 4 ) + 3 * 5"
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#test(exp)
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#exp = "2 * ( 3 + 4 ) + ( 3 - 4 ) * 5"
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#test(exp)
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#
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#exp = "2 * ( 2 - ( 3 + 4 ) ) + ( 3 - 4 ) * 5"
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#test(exp)
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#
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#exp = "2 * ( 2 - ( 3 + 4 ) ) + 5 * ( 3 - 4 )"
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#test(exp)
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#
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#exp = "2 + 5 * ( 3 - 4 )"
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#test(exp)
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#exp = "( 2 + 5 ) * ( 3 - 4 )^4"
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#test(exp)
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#exp = "( 2 + 5 ) * ( 3 * 4 )"
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#test(exp)
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#exp = "( 2 + 5 - 1 ) / ( 3 * 4 )"
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#test(exp)
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#exp = "( 2 + 5 ) / ( 3 * 4 ) + 1 / 12"
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#test(exp)
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#exp = "( 2+ 5 )/( 3 * 4 ) + 1 / 2"
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#test(exp)
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#exp="(-2+5)/(3*4)+1/12+5*5"
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#test(exp)
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#exp="-2*4(12 + 1)(3-12)"
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#test(exp)
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#exp="(-2+5)/(3*4)+1/12+5*5"
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#test(exp)
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# TODO: The next one doesn't work |ven. janv. 17 14:56:58 CET 2014
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#exp="-2*(-a)(12 + 1)(3-12)"
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#e = Expression(exp)
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#print(e)
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## Can't handle it yet!!
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#exp="-(-2)"
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#test(exp)
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#print("\n")
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#exp = Expression.random("({a} + 3)({b} - 1)", ["{a} > 4"])
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#for i in exp.simplify():
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# print(i)
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#import doctest
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#doctest.testmod()
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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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