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compute correctly

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Lafrite 2013-11-08 10:05:28 +01:00
parent 441af1dc10
commit 438d242b48
1 changed files with 82 additions and 30 deletions
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112
expression.py
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@ -20,14 +20,19 @@ class Expression(object):
elif type(exp) == list:
self.tokens = exp
self.find_fix() # Determine le fix et range la liste dans self.[fix]_tokens
self._infix_tokens = None
self._postfix_tokens = None
self.feed_fix() # Determine le fix et range la liste dans self.[fix]_tokens
## ---------------------
## Mechanism functions
def simplify(self, render = lambda x:str(x)):
""" Generator which return steps for computing the expression
@param render: function which render the list of token (postfix form now)
"""
if not self.can_go_further():
yield render(self.postfix_tokens)
@ -78,7 +83,7 @@ class Expression(object):
steps = expand_list(tmpTokenList)
if len(steps[:-1]) > 0:
self.steps += [steps[:-1]]
self.steps += steps[:-1]
self.child = Expression(steps[-1])
@ -109,7 +114,7 @@ class Expression(object):
@classmethod
def get_fix(self, tokens):
""" Give the "fix" of an expression
[A, +, B] -> infix
[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!
@ -120,12 +125,14 @@ class Expression(object):
"""
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 find_fix(self):
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)
@ -134,6 +141,7 @@ class Expression(object):
setattr(self, fix+"_tokens", self.tokens)
# ----------------------
# Expressions - tokens manipulation
@ -143,10 +151,10 @@ class Expression(object):
:returns: infix list of tokens
"""
if hasattr(self, "_infix_tokens"):
if self._infix_tokens:
return self._infix_tokens
elif hasattr(self, "_postfix_tokens"):
elif self._postfix_tokens:
self.post2in_fix()
return self._infix_tokens
@ -163,10 +171,10 @@ class Expression(object):
:returns: postfix list of tokens
"""
if hasattr(self, "_postfix_tokens"):
if self._postfix_tokens:
return self._postfix_tokens
elif hasattr(self,"_infix_tokens"):
elif self._infix_tokens:
self.in2post_fix()
return self._postfix_tokens
@ -180,13 +188,28 @@ class Expression(object):
# ----------------------
# "fix" tranformations
def in2post_fix(self):
""" From the self.infix_tokens list compute the corresponding self.postfix_tokens list """
#@classmethod
def in2post_fix(self, infix_tokens = None):
""" From the self.infix_tokens list compute the corresponding self.postfix_tokens list
@param infix_tokens: the infix list of tokens to transform into postfix form. If nothing is set, it takes the value self.infix_tokens
@return: the corresponding postfix list of tokens if infix_tokens is set. nothing otherwise but stock it in self.postfix_tokens
>>> Expression.in2post_fix(['(', 2, '+', 5, '-', 1, ')', '/', '(', 3, '*', 4, ')'])
[2, 5, '+', 1, '-', 3, 4, '*', '/']
"""
arg = 1
if infix_tokens == None:
arg = 0
infix_tokens = self._infix_tokens
# TODO: Trouver une autre méthode pour ne pas à avoir à utiliser cet attribu privé |dim. nov. 3 07:24:31 CET 2013
opStack = Stack()
postfixList = []
for token in self.infix_tokens:
for token in infix_tokens:
if token == "(":
opStack.push(token)
elif token == ")":
@ -205,13 +228,29 @@ class Expression(object):
while not opStack.isEmpty():
postfixList.append(opStack.pop())
self.postfix_tokens = postfixList
if not arg:
self.postfix_tokens = postfixList
else:
return postfixList
#@classmethod
def post2in_fix(self, postfix_tokens = None):
""" From the self.postfix_tokens list compute the corresponding self.infix_tokens list
@param postfix_tokens: the postfix list of tokens to transform into infix form. If nothing is set, it takes the value self.postfix_tokens
@return: the corresponding infix list of tokens if postfix_tokens is set. nothing otherwise but stock it in self.infix_tokens
>>> Expression.post2in_fix([2, 5, '+', 1, '-', 3, 4, '*', '/'])
['( ', 2, '+', 5, '-', 1, ' )', '/', '( ', 3, '*', 4, ' )']
"""
arg = 1
if postfix_tokens == None:
arg = 0
postfix_tokens = self._postfix_tokens
def post2in_fix(self):
""" From the self.postfix_tokens list compute the corresponding self.infix_tokens list """
operandeStack = Stack()
for token in postfixTokens:
for token in postfix_tokens:
if self.isOperator(token):
op2 = operandeStack.pop()
if self.needPar(op2, token, "after"):
@ -226,7 +265,12 @@ class Expression(object):
else:
operandeStack.push(token)
self.infix_tokens = flatten_list(operandeStack.pop())
infix_tokens = flatten_list(operandeStack.pop())
if not arg:
self.infix_tokens = infix_tokens
else:
return infix_tokens
# ---------------------
# Tools for placing parenthesis in infix notation
@ -327,23 +371,31 @@ class Expression(object):
def test(exp):
print(exp)
a = Expression(exp)
#for i in a.simplify(render = render):
for i in a.simplify():
print(i)
print("\n")
def render(tokens):
post_tokens = Expression.post2in_fix(tokens)
return ' '.join(post_tokens)
if __name__ == '__main__':
exp = "1 + 3 * 5"
test(exp)
exp = "2 * 3 * 3 * 5"
test(exp)
#exp = "2 * 3 * 3 * 5"
#test(exp)
exp = "2 * 3 + 3 * 5"
test(exp)
#exp = "2 * ( 3 + 4 ) + 3 * 5"
#test(exp)
#
exp = "2 * ( 3 + 4 ) + 3 * 5"
test(exp)
#exp = "2 * ( 3 + 4 ) + ( 3 - 4 ) * 5"
#test(exp)
#
@ -355,15 +407,15 @@ if __name__ == '__main__':
#
#exp = "2 + 5 * ( 3 - 4 )"
#test(exp)
#
#exp = "( 2 + 5 ) * ( 3 - 4 )"
#test(exp)
#
#exp = "( 2 + 5 ) * ( 3 * 4 )"
#test(exp)
#
#exp = "( 2 + 5 - 1 ) / ( 3 * 4 )"
#test(exp)
exp = "( 2 + 5 ) * ( 3 - 4 )"
test(exp)
exp = "( 2 + 5 ) * ( 3 * 4 )"
test(exp)
exp = "( 2 + 5 - 1 ) / ( 3 * 4 )"
test(exp)
#exp = "( 2 + 5 ) / ( 3 * 4 ) + 1 / 12"
#test(exp)