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

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From: Daniel Mendler <mail <at> daniel-mendler.de>
To: Pip Cet <pipcet <at> protonmail.com>
Cc: 78162 <at> debbugs.gnu.org, Stefan Kangas <stefankangas <at> gmail.com>
Subject: bug#78162: [PATCH] hash-table-contains-p: Avoid creating a symbol on every call
Date: Thu, 01 May 2025 17:37:19 +0200

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.

> Pip

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