At 10:16 AM 5/3/2007 -0400, Jim Jewett wrote: >On 5/3/07, Greg Ewing <[EMAIL PROTECTED]> wrote: > > > I don't doubt that things like @before and @after are > > handy. But being handy isn't enough for something to > > get into the Python core. > >I hadn't thought of @before and @after as truly core; I had assumed >they were decorators that would be available in a genfunc module.
Everything in the PEP is imported from an "overloading" module. I'm not crazy enough to try proposing any built-ins at this point. >(2) The explicit version of next_method corresponds to super, but is >uglier in practice, becaues their isn't inheritance involved. My >strawman would boil down to... > > def foo():... > next_method = GenFunc.dispatch(*args, after=__this_function__) Keep in mind that the same function can be re-registered under multiple rules, so a reference to the function is insufficient to specify where to chain from. Also, your proposal appears to be *re-dispatching* the arguments. My implementation doesn't redispatch anything; it creates a chain of method objects, which each know their next method. These chains are created and cached whenever a new combination of methods is required. In RuleDispatch, the chains are actually linked as bound method objects, so that a function's next_method is bound as if it were the "self" of that function. Thus, calling the next method takes advantage of Python's "bound method" optimizations. >Note that the overriding function foo would need to have both a >reference to itself (as opposed to its name, which will often be bound >to somthing else) and to the generic function from which it is being >called (and it might be called from several such functions). >Arranging this during the registration seems like an awaful lots of >work to avoid @after Yep, it's a whole lot simpler just to provide the next_method as an extra argument. _______________________________________________ Python-3000 mailing list Python-3000@python.org http://mail.python.org/mailman/listinfo/python-3000 Unsubscribe: http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
