I used to be in this "camp", however, a (I think valid) point was raised that "else:" is not a (full) alternative. Due to the restriction on repeated names (e.g. Point(x, x) is illegal), if you want to "throw away" intermediate matches, you will have to either have to come up with new names (Point(unused_1, unused_2)) or use the "_" as currently instituted (Point(_, _)) and "else:" does not cover that insofar as I can tell.

Personally I think using _ as throwaway name is perfectly fine, as it is in the rest of Python. The only exception would then be that _ is allowed to be repeated, whereas other identifiers aren't. I'd be ok with that.

What I don't like is the use of _ as catch-all, which is different and not interdependent with its use as throwaway.

On 08/07/2020 07:26, Steven Barker wrote:

To sum up, I feel like using constructor and keyword-argument syntax to access attributes is an abuse of notation. I'd much prefer a new syntax for matching classes and their attributes that was not so likely to be confusing due to imperfect parallels with class construction.

Ideally something like Datetime.year=x would be in my opinion clear at a glance (and reference vs. assignment could be accomplished simply by having == for reference and = for assignment), but it's problematic when it comes to mentioning multiple attributes.
A couple ideas:

1. Datetime[year=x, months==3, days==SOME_CONST]

2. (Datetime.year=x, months==3, days==SOME_CONST)

3. Datetime.year=x .months==3 .days==SOME_CONST

4. Datetime.year=x, .months==3, .days==SOME_CONST

With no class, this would perhaps favour usage of = and/or == before names to resolve the reference vs. assignment dispute.