[PATCHv2] gdbserver: Add .dir-locals.el file

[Andrew Burgess]

* Eli Zaretskii <eliz@gnu.org> [2020-03-02 21:19:18 +0200]:

> > Cc: andrew.burgess@embecosm.com, gdb-patches@sourceware.org
> > From: Pedro Alves <palves@redhat.com>
> > Date: Mon, 2 Mar 2020 18:12:53 +0000
> > 
> > > Put a single file in the parent directory of those 3, I think.
> > 
> > Good point.  This would affect all projects in the top level,
> > though perhaps the file is right for all of them.  
> 
> You can arrange for the settings to affect only some of the
> subdirectories, the Emacs manual shows an example of that.

I took a look at the examples, and, if I understand correctly I would
need to do something like:

  (("gdb/" . ((tcl-mode . (... settings ...))
              (nil . (... settings ...))
              (c-mode . (... settings ...))
              (c++-mode . (... settings ...))))
   ("gdbserver/" . ((tcl-mode . (... settings ...))
                    (nil . (... settings ...))
                    (c-mode . (... settings ...))
                    (c++-mode . (... settings ...))))
   ("gdbsupport/" . ((tcl-mode . (... settings ...))
                     (nil . (... settings ...))
                     (c-mode . (... settings ...))
                     (c++-mode . (... settings ...)))))

As there's no easy way (I think) to define a list of settings then
apply them to multiple directories.

Given how rarely the .dir-locals files change, my instinct is to just
add two new copies, and possibly ensure that all three versions of the
file have a big comment saying "remember to update the other versions
of this file located in ......".

Thoughts welcome,

thanks,
Andrew



> 
> > OOC, if we wanted to say, source "../gdb/.dir-locals.el" from
> > a gdbserver/.dir-locals.el file, would it be possible?
> 
> .dir-locals.el supports 'eval' forms, so you could in principle do
> anything there.  But my advice is to stick to simplicity, for reasons
> of speed of visiting files, if nothing else.  Also, maintaining such a
> tricky file would need an Emacs expert, something that is not
> guaranteed (although currently we have several on board).
> 
> > I guess a symlink would do too.  Except that might not work
> > as nicely on Windows filesystems.
> 
> IME, symlinks in versioned directories are a PITA.