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Use isinstance rather than comparing class attribute

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This allows to create subclasses
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Salvo 'LtWorf' Tomaselli 2015-07-14 11:09:42 +02:00
parent 73dd14d9dd
commit f787630edb
1 changed files with 6 additions and 4 deletions
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10
relational/relation.py
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@ -94,7 +94,7 @@ class relation (object):
It is not exactely related to relational algebra. Just a method used It is not exactely related to relational algebra. Just a method used
internally. internally.
Will raise an exception if they don't share the same attributes''' Will raise an exception if they don't share the same attributes'''
if (self.__class__ != other.__class__): if not isinstance(other, relation):
raise Exception('Expected an instance of the same class') raise Exception('Expected an instance of the same class')
elif self.header == other.header: elif self.header == other.header:
return other return other
@ -113,7 +113,7 @@ class relation (object):
# Fills the attributes dictionary with the values of the tuple # Fills the attributes dictionary with the values of the tuple
attributes = {attr: i[j].autocast() attributes = {attr: i[j].autocast()
for j, attr in enumerate(self.header) for j, attr in enumerate(self.header)
} }
try: try:
if eval(expr, attributes): if eval(expr, attributes):
@ -129,7 +129,9 @@ class relation (object):
cause an exception. cause an exception.
It is possible to use rename on attributes and then use the product''' It is possible to use rename on attributes and then use the product'''
if (self.__class__ != other.__class__)or(self.header.sharedAttributes(other.header) != 0): if (not isinstance(other, relation)):
raise Exception('Operand must be a relation')
if self.header.sharedAttributes(other.header) != 0:
raise Exception( raise Exception(
'Unable to perform product on relations with colliding attributes' 'Unable to perform product on relations with colliding attributes'
) )
@ -347,7 +349,7 @@ class relation (object):
def __eq__(self, other): def __eq__(self, other):
'''Returns true if the relations are the same, ignoring order of items. '''Returns true if the relations are the same, ignoring order of items.
This operation is rather heavy, since it requires sorting and comparing.''' This operation is rather heavy, since it requires sorting and comparing.'''
if self.__class__ != other.__class__: if not isinstance(other, relation):
return False return False
if set(self.header) != set(other.header): if set(self.header) != set(other.header):