On Mon, Sep 5, 2016 at 5:02 PM, Nick Coghlan <ncogh...@gmail.com> wrote: > On 5 September 2016 at 23:46, Nick Coghlan <ncogh...@gmail.com> wrote: >> Under such "parameter annotation like" semantics, uninitialised >> variable annotations would only make sense as a new form of >> post-initialisation assertion,
Why not discuss this in the python-ideas thread where I quote myself from last Friday regarding the notion of annotations as assertions? >> and perhaps as some form of >> Eiffel-style class invariant documentation syntax. I hope this is simpler than it sounds :-) > Thinking further about the latter half of that comment, I realised > that the PEP 484 equivalence I'd like to see for variable annotations > in a class body is how they would relate to a property definition > using the existing PEP 484 syntax. > > For example, consider: > > class AnnotatedProperty: > > @property > def x(self) -> int: > ... > > @x.setter > def x(self, value: int) -> None: > ... > > @x.deleter > def x(self) -> None: > ... > > It would be rather surprising if that typechecked differently from: > > class AnnotatedVariable: > > x: int > How about just using the latter way? That's much clearer. I doubt this needs a change in the PEP. > For ClassVar, you'd similarly want: > > > class AnnotatedClassVariable: > > x: ClassVar[int] > > to typecheck like "x" was declared as an annotated property on the metaclass. > Sure, there are many things that one may consider equivalent. I doubt you'll be able to list them all in a way that everyone agrees on. And I hope you don't take this as a challenge -- I'm in the don't-panic camp :). -- Koos > Cheers, > Nick. > > -- > Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia -- + Koos Zevenhoven + http://twitter.com/k7hoven + _______________________________________________ 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
