bug#64735: 29.0.92; find invocations are ~15x slower because of ignores

[Eli Zaretskii]

> From: Ihor Radchenko <yantar92@posteo.net>
> Cc: sbaugh@catern.com, sbaugh@janestreet.com, dmitry@gutov.dev,
>  michael.albinus@gmx.de, rms@gnu.org, 64735@debbugs.gnu.org
> Date: Sat, 22 Jul 2023 15:07:45 +0000
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> > So I think a primitive that traverses the tree and produces file names
> >> > with or without attributes, and can call some callback if needed,
> >> > still has its place.
> >> 
> >> Do you mean asynchronous primitive?
> >
> > No, a synchronous one.
> 
> Then how will the callback be different from
> (mapc #'my-function (directory-files-recursively ...))
> ?

It depends on the application.  Applications that want to get all the
data and only after that process it will not use the callback.  But I
can certainly imagine an application that inserts the file names, or
some of their transforms, into a buffer, and from time to time
triggers redisplay to show the partial results.  Or an application
could write the file names to some disk file or external consumer, or
send them to a network process.