bug#63744: 28.2; fix dired-guess-default

[Eli Zaretskii]

> From: Leo Liu <sdl.web@gmail.com>
> Date: Tue, 30 May 2023 02:20:28 +0800
> 
> On 2023-05-29 15:07 +0300, Eli Zaretskii wrote:
> > Does this answer my question above?  If so, I don't think I understand
> > the answer, please elaborate.  I asked why not generate the whole
> > value, including the REGEXP part, dynamically.
> 
> I thought you would have grasped the problem by now ;)
> 
> "I asked why not generate the whole value, including the REGEXP part,
> dynamically."
> 
> This is a static list.
> 
> The problem we are trying to solve here is we don't know the list until
> we know the FILE. Even when given the FILE we may still have imperfect
> knowledge about which tools can handle it.
> 
> For example, On my Mac an html file can be handled by 10 apps at the
> moment including all browsers and Emacs and more. It may change next
> minute when some apps are installed or uninstalled or file association
> changed.

I understand all that.  But you are evidently still not understanding
what I'm asking.  Never mind, I give up.  Some kind of failure to
explain myself.

Bottom line: we can extend the feature the way you'd like, but it will
need be installed on master, and will have to wait for Emacs 30.