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bug#73853: 31.0.50; and-let* is useless
From: |
Michael Heerdegen |
Subject: |
bug#73853: 31.0.50; and-let* is useless |
Date: |
Sat, 19 Oct 2024 05:50:49 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) |
Stefan Monnier <monnier@iro.umontreal.ca> writes:
> But there isn't the same "historical" support that justifies having
> both, and the syntax&semantics of `and-let*` is just weird:
>
> - Why allow a BODY if the motivation is to mirror the normal `and`?
> If you want a BODY, use `when-let*`.
> - What's the use of the final variable binding since (assuming you
> don't use BODY) that variable is never used:
>
> (and-let* ((a (fooa))
> (b (foob a))
> (i-m-useless (fooc a b))))
One could say BODY _is_ the final condition and therefore it has a
special syntax because it necessarily doesn't need a binding. That way
I've my peace with that syntax.
Anyway, removing `and-let*' would be equally unsatisfying, and
obviously, at least one the two points will remain unless we change
the syntax radically - or remove `and-let*' :-(
> - There's a special syntax where the final binding can drop the variable
> name (because of the previous point), which makes for an odd syntax
>
> (and-let* ((a (fooa))
> (b (foob a))
> ((weird-call a b))))
That I feel too. As an alternative we made the pseudo variable _ work
without compiler warnings. But one gets used to the variable-less
syntax. It's too handy...
> So the use with BODY is redundant with `when-let*` and the use without
> BODY is quirky (and still redundant with `when-let*`, of course).
I see your points, but don't consider them as such a big problem.
Anyway, without having something that is obviously better the discussion
remains quite philosophical. And replacing calls of `and-let*' with
equivalent calls of `when-let*' doesn't make code easier to read, IMO.
> 100% agreement. Can we `make-obsolete` the non-star versions?
I hope we can.
Michael.
- bug#73853: 31.0.50; and-let* is useless, Stefan Monnier, 2024/10/17
- bug#73853: 31.0.50; and-let* is useless, Sean Whitton, 2024/10/18
- bug#73853: 31.0.50; and-let* is useless, Stefan Kangas, 2024/10/20
- bug#73853: 31.0.50; Should and-let* become a synonym for when-let*?, Sean Whitton, 2024/10/22
- bug#73853: 31.0.50; Should and-let* become a synonym for when-let*?, Michael Heerdegen, 2024/10/22
- bug#73853: 31.0.50; Should and-let* become a synonym for when-let*?, Stefan Kangas, 2024/10/23
- bug#73853: 31.0.50; Should and-let* become a synonym for when-let*?, Sean Whitton, 2024/10/24
- bug#73853: 31.0.50; Should and-let* become a synonym for when-let*?, Sean Whitton, 2024/10/25