bug#44529: [PATCH] Convert apropos-internal from C to Lisp

[Stefan Kangas <stefan@marxist.se>]

Eli Zaretskii <eliz@gnu.org> writes:

>> (benchmark-run 10
>>   (apropos "x"))
>> => (3.846117816 131 1.092690677) ; C
>> => (4.218219444 145 1.2153865740000003) ; Lisp
>
> 20% slowdown is not negligible, at least not in principle.  Let's wait
> for more people to voice their opinions on this aspect.

Unless I'm missing something, the slowdown should be around 10%.

(FWIW, the figure of 0.38 or 0.42 seconds is for the more unlikely
string with one character.  In the more realistic scenario with a
slightly longer string, we see a difference between 0.012 and 0.013
seconds.)

> A bother: apropos.el is not preloaded, so please double-check that
> none of the preloaded files call apropos-internal, otherwise that
> would mean we need to preload apropos.el, which I think is
> undesirable.

I only see one call in a preloaded file:

./lisp/progmodes/elisp-mode.el:873: (dolist (sym (apropos-internal regexp))

(This is from a `cl-defmethod' for `xref-backend-apropos'.)

Does this mean we have to preload apropos.el?  I don't understand how,
so I'm probably missing something.

Thanks for commenting.