On 21 April 2015 at 17:59, Guido van Rossum <gu...@python.org> wrote: > For me, PEP 484 is a stepping stone. Among the authors of PEP 484 there was > much discussion about duck typing, and mypy even has some limited support > for duck typing (I think you can still find it by searching the mypy code > for "protocol"). But we ran out of time getting all the details written up > and agreed upon, so we decided to punt -- for now. But duck typing still > needs to have a way to talk about things like "seek method with this type > signature" (something like `def seek(self, offset: int, whence: > int=SEEK_SET) -> int`) so the current proposal gets us part of the way > there. > > The hope is that once 3.5 is out (with PEP 484's typing.py included > *provisional* mode) we can start working on the duck typing specification. > The alternative would have been to wait until 3.6, but we didn't think that > there would be much of an advantage to postponing the more basic type > hinting syntax (it would be like refusing to include "import" until you've > sorted out packages). During the run of 3.5 we'll hopefully get feedback on > where duck typing is most needed and how to specify it -- valuable input > that would be much harder to obtain of *no* part of the type hints notation > were standardized.
This makes a lot of sense. If PEP 484 is intended to be a stepping stone (or compromise, or beta, or whatever word one wants to use), then it is easy to forgive it its limitations, and I'm looking forward to seeing it improve. _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
