On Thu, Feb 20, 2014 at 10:28 PM, Marko Rauhamaa <ma...@pacujo.net> wrote: > Chris Angelico <ros...@gmail.com>: > >> On Thu, Feb 20, 2014 at 9:22 PM, Marko Rauhamaa <ma...@pacujo.net> wrote: >>> py35.unless x > 7: >>> return >> >> What about return? Are you allowed to namespace that? And 'from' and >> 'import' and '*'? > > Old keywords are guaranteed not to clash with programs. Introducing new > keywords runs that risk. Hence, C had to introduce the ugly _Bool > keyword.
Okay, so what you're saying is that there are three states: Before Python X.Y, the unless keyword simply doesn't exist. (It can't be coded in as a module, so it can't exist until someone implements the code.) >From X.Y, it can be called up by importing it from "pyAB" and used in its namespace. >From A.B onward, it always exists. Python has a facility like this. It doesn't namespace the keywords, but it does let you choose whether to have them or not. In Python 2.5, you could type "from __future__ import with_statement" to turn 'with' into a keyword. After Python 2.6, it's always a keyword. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
