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# Copyright (c) 2010 Mark Sandstrom
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
class OrderedDeclaration(object):
'''A factory declaration.
Ordered declarations keep track of the order in which they're defined so that later declarations
can refer to attributes created by earlier declarations when the declarations are evaluated.'''
_next_order = 0
def __init__(self):
self.order = self.next_order()
@classmethod
def next_order(cls):
next_order = cls._next_order
cls._next_order += 1
return next_order
def evaluate(self, factory, attributes):
'''Evaluate this declaration.
Args:
factory: The factory this declaration was defined in.
attributes: The attributes created by the unordered and ordered declarations up to this point.'''
raise NotImplementedError('This is an abstract method')
class LazyAttribute(OrderedDeclaration):
def __init__(self, function):
super(LazyAttribute, self).__init__()
self.function = function
def evaluate(self, factory, attributes):
return self.function(attributes)
class Sequence(OrderedDeclaration):
def __init__(self, function, type=str):
super(Sequence, self).__init__()
self.function = function
self.type = type
def evaluate(self, factory, attributes):
return self.function(self.type(factory.sequence))
class LazyAttributeSequence(Sequence):
def evaluate(self, factory, attributes):
return self.function(attributes, self.type(factory.sequence))
# Decorators... in case lambdas don't cut it
def lazy_attribute(func):
return LazyAttribute(func)
def sequence(func):
return Sequence(func)
def lazy_attribute_sequence(func):
return LazyAttributeSequence(func)
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