Paul Moore wrote: > My point was that as far as I am aware, > Guido's current position on ABCs is that they are, and will remain, > optional - people like myself (and Greg, from the sound of it) who > don't want to derive from ABCs will not be penalised by being excluded > from anything in the Python core or the stdlib.
Maybe not in the core or stdlib, but it seems like there will be cases where one *is* penalised for not using the ABCs, if they get used the way the PEP proposes. From the PEP, it seems there are two purposes for these proposed ABCs: 1) To document what is meant when we say that something is a "sequence", "mapping", etc. This could be done simply by writing documentation. There is no need for anything embodied in the language. 2) To mark a class for the purposes of introspection. I thought we had generally agreed that this is an anti-pattern in Python. If I want my object to interoperate with someone else's code that tests for the presence of some ABC, then I *am* forced to use that ABC, even if it doesn't entirely suit my purposes. I'm -1 on including anything in the language, stdlib or docs that appears to officially sanction type testing as a normal style of programming. -- 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
