GNU bug report logs - #78162
[PATCH] hash-table-contains-p: Avoid creating a symbol on every call

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From: Eli Zaretskii <eliz <at> gnu.org>
To: Daniel Mendler <mail <at> daniel-mendler.de>, Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 78162 <at> debbugs.gnu.org, pipcet <at> protonmail.com, stefankangas <at> gmail.com
Subject: bug#78162: [PATCH] hash-table-contains-p: Avoid creating a symbol on every call
Date: Sat, 10 May 2025 13:19:10 +0300

> Cc: 78162 <at> debbugs.gnu.org, Stefan Kangas <stefankangas <at> gmail.com>
> Date: Thu, 01 May 2025 17:37:19 +0200
> From:  Daniel Mendler via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs <at> gnu.org>
> 
> Pip Cet <pipcet <at> protonmail.com> writes:
> 
> > "Daniel Mendler" <mail <at> daniel-mendler.de> writes:
> >
> >> Pip Cet <pipcet <at> protonmail.com> writes:
> >>
> >>> "Daniel Mendler via \"Bug reports for GNU Emacs, the Swiss army knife of text editors\"" <bug-gnu-emacs <at> gnu.org> writes:
> >>>
> >>>> Tags: patch
> >>>>
> >>>> For performance reasons avoid creating a symbol on every call to
> >>>> `hash-table-contains-p'.  See also https://github.com/emacs-compat/compat/issues/71.
> >>>
> >>> If the performance of hash-table-contains-p is an issue, we should
> >>> reimplement it in C, which can use magic values which aren't accessible
> >>> from Lisp.
> >>
> >> For a proper hash table I expect this function to be efficient and not
> >> allocate.
> >
> > C would work, then.  As it avoids both your performance concerns and my
> > concerns about leaking magic values to Lisp, how about this?
> 
> Looks good. Thanks.

Stefan, any comments to the patch?

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