bug#59888: [PATCH] Add 'grep-heading-mode'

[Eli Zaretskii <eliz@gnu.org>]

> From: Augusto Stoffel <arstoffel@gmail.com>
> Cc: 59888@debbugs.gnu.org
> Date: Thu, 08 Dec 2022 09:59:46 +0100
> 
> On Wed,  7 Dec 2022 at 20:14, Eli Zaretskii wrote:
> 
> >> From: Augusto Stoffel <arstoffel@gmail.com>
> >> Date: Wed, 07 Dec 2022 18:57:37 +0100
> >> 
> >> +(defcustom grep-heading-regexp
> >> +  (rx bol
> >> +      (or
> >> +       (seq "Grep" (* (any "/a-zA-Z")) " "
> >> +            (or "started" "finished" "exited" "interrupt" "killed" "terminated")
> >
> > Cannot these be translated to languages other than English in
> > localized versions of Grep?
> 
> AFAICT these messages are generated by Emacs itself.

All of them?

> We could also use "^Grep[/a-zA-Z]* [^\0t\]*$" here

The [/a-zA-Z] part is still ASCII-only, and I believe the "/" part
means you want to support file names? then for Windows we also need
the colon ':'.

> >> 2. One could get rid of the awkward first alternative of
> >>    `grep-heading-regexp' if there was a way to distringuish the grep
> >>    process output from the header and footer added by grep-mode.
> >
> > You could put a special text property on the latter, no?
> 
> That's an option and it would be useful for other extensions as well.
> So we would define something like
> 
> --8<---------------cut here---------------start------------->8---
> (defun compilation-insert-note (&rest args)
>   (let ((start (point)))
>     (apply #'insert args)
>     (put-text-property start (point) 'compilation-note t)))
> --8<---------------cut here---------------end--------------->8---
> 
> and use throughout compile.el, right?

Yes, something like this.