On Mon, Jan 17, 2022 at 10:12 AM Sebastian Rittau <srittau@rittau.biz> wrote:
Am 17.01.22 um 17:38 schrieb Paul Bryan:
As a static type checking amateur, it's not clear to me what the aim of adding this to stdlib is. Is this to avoid the pitfalls of code containing calls to `reveal_type` when not running mypy or other static type checker? Is the intent for the static type checker to monkey-patch the typing library to provide something different when it's running?
This is an idea I wanted to bring up as well, but never came around to. For me, it's mostly about convenience: Often when debugging, I add reveal_type() statements and run the type checker and the tests alternately. But currently this means I have to remember to comment out the reveal_type() statement whenever I run the tests (and I usually don't remember). This would help with this nuisance.
Indeed -- I have used this workflow (alternating between running a static checker and running the code) and sometimes I've even done things like if not TYPE_CHECKING: reveal_type = print # Good enough :-) Still, I have a concern. Linters etc. tend to complain about unused imports. That means that you cannot leave the `from typing import reveal_type` in your code once you've removed the last reveal_type() call. But now when you want to use it, you'll have to add the import back in. So it would be much more convenient if it was an actual builtin. Regarding reveal_locals(), that's much less commonly used in my experience (it was added to mypy rather late) and I am hesitant to standardize it prematurely. (Alas, spotting usage "in the wild" of these functions is not easy, since their essence is that you have to remove them before running your code.) -- --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-c...>