Fredrik Lundh wrote: > George Sakkis wrote: > > > The base object class would be one candidate, similarly to the way > > __nonzero__ is defined to use __len__, or __contains__ to use __iter__. > > > > Alternatively, iter() could be a wrapper type (or perhaps mixin) > > instead of a function, something like: > > so you're proposing to either make *all* objects respond to "+", or > introduce limited *iterator* algebra.
If by 'respond to "+"' is implied that you can get a "TypeError: iterable argument required", as you get now for attempting "x in y" for non-iterable y, why not ? Although I like the iterator algebra idea better. > not sure how that matches the OP's wish for "mostly backwards > compatible" support for *iterable* algebra, really... Given the subject of the thread, backwards compatibility is not the main prerequisite. Besides, it's an *extension* idea; allow operations that were not allowed before, not the other way around or modifying existing semantics. Of course, programs that attempt forbidden expressions on purpose so that they can catch and handle the exception would break when suddenly no exception is raised, but I doubt there are many of those... George -- http://mail.python.org/mailman/listinfo/python-list
