On Sun, Feb 14, 2021 at 7:17 PM Inada Naoki <songofaca...@gmail.com> wrote:
> On Mon, Feb 15, 2021 at 10:20 AM Joseph Perez <jope...@hotmail.fr> wrote: > > > > > How about having a pseudo-module called __typing__ that is > > > ignored by the compiler: > > > > > > from __typing__ import ... > > > > > > would be compiled to a no-op, but recognised by type checkers. > > > > If you want to do run-time typing stuff, you would use > > There is already a way of doing that: `if typing.TYPE_CHECKING: ...` > https://docs.python.org/3/library/typing.html#typing.TYPE_CHECKING > > But yes, the issue with it is that this constant is defined in the > `typing` module … > > > > However, I think this is a part of the solution. Indeed, the language > could define another builtin constants, let's name it `__static__`, which > would simply be always false (at runtime), while linters/type checkers > would use it the same way `typing.TYPE_CHECKING` is used: > > ```python > > if __static__: > > import typing > > import expensive_module > > ``` > > > Please note that this is a thread about PEP 649. > > If PEP 649 accepted and PEP 563 dies, all such idioms breaks > annotation completely. > > Users need to import all heavy modules and circular references used > only type hints, or user can not get even string form annotation which > is very useful for REPLs. > Hm, that's a rather serious problem with Larry's PEP 649 compared to `from __future__ import annotations`, actually. Larry, what do you think? -- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/>
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