On 5 Sep 2020 Ram Rachum firstname.lastname@example.org wrote:
Sorry if this was proposed already. I looked here https://www.python.org/dev/peps/pep-0622/#alternatives-for-constant-value-pa..., search for "idea to make lookup semantics the default". I saw that a few symbols like $ and ? were proposed, and I thought that maybe the annotation syntax -> could indicate a capture expression, like so:
case x: match Point(-> a, -> b): ... match -> whatever: do_something(whatever)
I like the arrow because it's easy to imagine the value "entering" the variable. What do you think?
Combined with keywords that could become: Point(x -> a, y -> b)
or, mixed with providing values: Point(x -> a, y=42)
And we wouldn’t need match -> whatever: because we already have x, and if x is an expression I’d prefer case x as whatever: