Phillip J. Eby wrote: > At 12:54 PM 7/24/2007 +1200, Greg Ewing wrote: >> When adding an overload to a GF, what methodology can I >> follow to ensure that my overload doesn't interact in an >> unfortunate way with another one somewhere else, perhaps >> one not written by me? > > What methodology can you follow that ensures that same thing when > overriding a method in a subclass?
It's dead simple -- my method always wins. This is true even in the presence of multiple inheritance. Problems only arise there if I use super() to make an inherited method call (so I don't do that) or if other people multiply inherit from me -- in which case it's their problem, not mine. > Okay, well I guess the above statements all put you squarely in the "OO > is too scary" category, Certainly not -- I don't find OO scary at all. I wouldn't say that I find GFs "scary" either, only that I would use them cautiously and sparingly. I don't agree that there is no difference between the traditional OO model and GFs. With GFs there is less static structure that you can rely on. >> And what if the program doesn't exist yet, because I'm >> still thinking about how to write it? Or it exists but >> isn't yet in a state where it can be run successfully? > > I don't understand what you're asking, here. Don't you think it's important to be able to reason about the way a program will behave while you're in the process of designing it? If you haven't written runnable code yet, you can't run it to get a list of method overrides. > I was under the impression that > under certain circumstances, if one object is "more specific" than the > other (i.e., one is an instance of a subclass of the other's type), then > that one gets first say. You may be right. But the fact remains that the method called will be a method of one class or the other -- it can't be some function defined in an arbitrary place. -- Greg _______________________________________________ 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
