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Diffstat (limited to 'factory/declarations.py')
| -rw-r--r-- | factory/declarations.py | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/factory/declarations.py b/factory/declarations.py new file mode 100644 index 0000000..37c8cbd --- /dev/null +++ b/factory/declarations.py @@ -0,0 +1,76 @@ +# 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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