CodePlex Issue #19821 Plain Text Attachments

noattr.py

import types

class cached_property(object):
    no_value = object()
    
    def __init__(self, fget):
        self.fget = fget
        self.name = '_' + fget.__name__
        
    def __get__(self, obj, cls):
        if obj is None:
            return self

        v = getattr(obj, self.name, cached_property.no_value)
        
        if v is cached_property.no_value:
            v = self.fget(obj)
            setattr(obj, self.name, v)
        
        return v
    
    def reset(self, obj, v=no_value):
        if v is cached_property.no_value:
            v = self.fget(obj)

        setattr(obj, self.name, v)
        return v

class Foo(object):
    @cached_property
    def bar(self):
        return self._attr_error();
    
    def _attr_error(self):
        return types.FunctionTyp
    
if __name__ == '__main__':
    f = Foo()
    print f.bar