bug#60525: 29.0.60; tree-sitter support in semantic-symref

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

>> >> On 03/01/2023 20:06, Juri Linkov wrote:
>> >> > +    (c-ts-mode "*.[ch]")
>> >> >       (c++-mode "*.[chCH]" "*.[ch]pp" "*.cc" "*.hh")
>> >> > +    (c++-ts-mode "*.[chCH]" "*.[ch]pp" "*.cc" "*.hh")
>> >> >       (html-mode "*.html" "*.shtml" "*.php")
>> >> >       (mhtml-mode "*.html" "*.shtml" "*.php") ; FIXME: remove
>> >> >                                               ; duplication of
>> >> > @@ -53,7 +55,10 @@ semantic-symref-filepattern-alist
>> >> >                                               ; major mode definition?
>> >> >       (ruby-mode "*.r[bu]" "*.rake" "*.gemspec" "*.erb" "*.haml"
>> >> >                  "Rakefile" "Thorfile" "Capfile" "Guardfile" "Vagrantfile")
>> >> > +    (ruby-ts-mode "*.r[bu]" "*.rake" "*.gemspec" "*.erb" "*.haml"
>> >> > +                  "Rakefile" "Thorfile" "Capfile" "Guardfile" "Vagrantfile")
>> >> >       (python-mode "*.py" "*.pyi" "*.pyw")
>> >> 
>> >> Instead of duplicating entries, we could try to look up the remappings 
>> >> in major-mode-remap-alist.
>> >
>> > That doesn't sound to me like the use of major-mode-remap-alist that
>> > was intended.
>> >
>> > I'm okay with duplication at this point.  It is much easier, and we
>> > can always augment or fix later as needed.  I see no reason to do
>> > anything fancier at this point.
>> >
>> > Stefan, Lars, WDYT?
>> 
>> I'll just note that the above alists already duplicate info present in
>> `auto-mode-alist`.  Admittedly, this redundant info is present in
>> a different form, so maybe not directly usable as is, but if we care
>> about redundancy, we should maybe add some layer on top which we can
>> then use both for `semantic-symref-filepattern-alist` and for
>> `auto-mode-alist`.
>
> I' aware of the redundancy.  But since we decided to go with those
> separate modes in Emacs 29, I think the redundancy is in general
> unavoidable.  If we can use the fact that auto-mode-alist already
> mentions both modes, and we can do that cleanly, it's fine by me.
> Otherwise we will have to live with this for now.

BTW, other ways to reduce the redundancy (not between
`semantic-symref-filepattern-alist` and `auto-mode-alist`, but the one
introduced by the patch above):

- make the various variants of a major mode all inherit from a shared
  parent mode (and then use that shared parent mode in
  `semantic-symref-filepattern-alist`).

- Use `set-auto-mode--last` which remembers the mode specified before it
  was remapped by things like `major-mode-remap-alist` (or by dispatch
  functions like `tex-mode`).


        Stefan