On Thu, 07 Feb 2008 18:22:03 +0100, Diez B. Roggisch <[EMAIL PROTECTED]> wrote: > Can you provide an example of what you are actually after? The > descriptor-protocol might come to use there.
Thanks for your responses. I have read the Descriptor protocol how-to, which clarifies method access on objects, and indeed provides a solution. My idea was to have some @pre and @post decorators, which check some pre-conditions. When applied to a method, the first parameter will be an instance-object, and I wondered whether I could detect whether the precondition cared about it or not. So, @pre(lambda x: x > 0) def method(self, x): Here the precondition function does not use 'self', yet it will of course be provided in a call, so I need to strip it. In case of a @pre applied to a function, this does not happen. I'm not sure whether this magic is such a nice solution though. However, the descriptor protocol indeed is what I need. If I provide the __get__ method, this will be invoked instead of __call__, which will happen on functions (or methods, if __get__ is not provided). This way the two are clearly distinguishable, and I need not worry about heuristics (such as, is the first parameter called 'self' or something). Besides, it taught me a bit more about the inner design of Python. :) Thanks, Berteun -- http://mail.python.org/mailman/listinfo/python-list
