Source code for pytraits.extendable

#!/usr/bin/python -tt
# -*- coding: utf-8 -*-
'''
   Copyright 2014-2015 Teppo Perä

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
'''

from pytraits.trait_composer import add_traits


[docs]def extendable(target): """ Decorator that adds function for object to be extended using traits. NOTE: The 'add_traits' function this extendable decorator adds contains behavior that differs from usual function behavior. This method alters its behavior depending is the function called on a class or on an instance. If the function is invoked on class, then the class gets updated by the traits, affecting all new instances created from the class. On the other hand, if the function is invoked on an instance, only that instance gets the update, NOT whole class. See complete example from: pytraits/examples/extendable_function_class_vs_instance.py >>> @extendable ... class ExampleClass: ... pass ... >>> hasattr(ExampleClass, 'add_traits') True >>> class InstanceExample: ... pass ... >>> instance_example = InstanceExample() >>> _ = extendable(instance_example) >>> hasattr(instance_example, 'add_traits') True """ class TypeFunction: def __init__(self): self._target_object = None def __call__(self, *args, **kwargs): add_traits(self._target_object, *args, **kwargs) def __get__(self, instance, clazz): self._target_object = instance or clazz return self target.add_traits = TypeFunction() return target
if __name__ == '__main__': import doctest doctest.testmod()