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copied!<p>There is no reasonable way to make this "class property" system to work in Python.</p> <p>Here is one unreasonable way to make it work. You can certainly make it more seamless with increasing amounts of metaclass magic.</p> <pre><code>class ClassProperty(object): def __init__(self, getter, setter): self.getter = getter self.setter = setter def __get__(self, cls, owner): return getattr(cls, self.getter)() def __set__(self, cls, value): getattr(cls, self.setter)(value) class MetaFoo(type): var = ClassProperty('getvar', 'setvar') class Foo(object): __metaclass__ = MetaFoo _var = 5 @classmethod def getvar(cls): print "Getting var =", cls._var return cls._var @classmethod def setvar(cls, value): print "Setting var =", value cls._var = value x = Foo.var print "Foo.var = ", x Foo.var = 42 x = Foo.var print "Foo.var = ", x </code></pre> <p>The knot of the issue is that properties are what Python calls "descriptors". There is no short and easy way to explain how this sort of metaprogramming works, so I must point you to the <a href="http://users.rcn.com/python/download/Descriptor.htm" rel="noreferrer">descriptor howto</a>.</p> <p>You only ever need to understand this sort of things if you are implementing a fairly advanced framework. Like a transparent object persistence or RPC system, or a kind of domain-specific language.</p> <p>However, in a comment to a previous answer, you say that you </p> <blockquote> <p>need to modify an attribute that in such a way that is seen by all instances of a class, and in the scope from which these class methods are called does not have references to all instances of the class.</p> </blockquote> <p>It seems to me, what you really want is an <a href="http://en.wikipedia.org/wiki/Observer_pattern" rel="noreferrer">Observer</a> design pattern.</p>

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