Blair <bidih...@gmail.com> added the comment: I am happy to collaborate in finding a solution, but I do not have enough knowledge or skill to work with the code alone.
Simply documenting it does not remove the frustration that a few people will enounter. The key point being that you can subclass the other numeric types, but not complex. Worse, you may think that you have succeeded in subclassing complex too, because it is only when the __ropn__ binary operators are used that the type reverts to the base class type. Would you want to subclass a numeric type? I agree, it is a bit obsure, but I did a search on this before making the post and there have been others who found the problem too. In my case, I think that the motivation may seem a bit obscure. I had developed some numerical-like types (from scratch -- no subclassing) and I wanted to be able to write functions taking as possible arguments these types and Python numerical types indifferently. I realised that I could not achieve exactly what I wanted, however, by subclassing float, int, etc I could add a few methods that would allow my generic functions to work with either my types or the subclassed Python types. At the same time, the subclassed numerical types could still be used as numerical quantities (float, int,...). It seemed like a pretty elegant solution. If that explanation does not make sense, then I suppose other simpler motivations could be, eg, to subclass float so that only positive values are acceptable; to subclass complex so that only values lying within the unit circle are acceptable, etc. That is, one might like to define a type that can only take on physically meaningful values (mass cannot be negative, a complex reflection coeffcieint cannot have a magnitude greater than unity, ..) So, my feeling is that this is worth fixing because the work done on float, int etc, is clearly useful and it appears (to me) that the complex case is an oversight. _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue5211> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
