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bug#49809: [PATCH] Add macro 'pcase-setq'
From: |
Stefan Monnier |
Subject: |
bug#49809: [PATCH] Add macro 'pcase-setq' |
Date: |
Thu, 05 Aug 2021 09:34:55 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) |
Michael Heerdegen [2021-08-05 03:02:03] wrote:
> Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of
> text editors" <bug-gnu-emacs@gnu.org> writes:
>
>> Looks good.
>
> How much trouble would it be to provide a `setf' variant?
>
> A problem could be any syntax that is used for both pcase patterns and
> place expressions I guess.
Adding support for (setf (pcase PAT) VAL) is very easy to do without any
change to pcase or gv machinery.
Adding support for (setf PAT VAL), is a bit harder (and introduces
a risk because of the potential overlap, tho this risk is small: gv
places are normally defined for "eliminators" whereas pcase patterns are
usually defined for "constructors"), but still fairly easy.
Mixing pcase patterns and gv places as in
(setf `(,a . ,(aref V N)) EXP)
would be the most flexible option but I haven't thought much about how
hard it would be to implement, and I'm not sure it's worth the trouble.
Stefan
bug#49809: [PATCH] Add macro 'pcase-setq', Okam, 2021/08/06
- bug#49809: [PATCH] Add macro 'pcase-setq', Michael Heerdegen, 2021/08/06
- bug#49809: [PATCH] Add macro 'pcase-setq', Lars Ingebrigtsen, 2021/08/11
- bug#49809: [PATCH] Add macro 'pcase-setq', Michael Heerdegen, 2021/08/12
- bug#49809: [PATCH] Add macro 'pcase-setq', Okam, 2021/08/12
- bug#49809: [PATCH] Add macro 'pcase-setq', Stefan Monnier, 2021/08/12