Re: Emacs in multiple profiles

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi Pierre,

Pierre Neidhardt <mail@ambrevar.xyz> writes:

> Hi!
>
> I'm resurrecting this since I got bitten by this today.
>
> I'm currently writing a blog article on profiles and manifest, and I
> realized that Emacs is the only program so far that does not behave
> consistently with the rest of Guix.
>
> When I source the etc/profile where I've installed my Emacs packages,
> I'd expect the appropriate environment variables to be set so that
> `guix-emacs-autoload-packages' knows where to load the packages from.
>
> I believe the solution to be simple:
>
> 1. Make Emacs packages set XDG_DATA_DIRS in etc/profile
> 2. guix-emacs.el: Remove guix-user-profile
> 3. guix-emacs.el: Set profiles to all the paths in XDG_DATA_DIRS in the
> guix-emacs-autoload-packages function.
>
> Thoughts?

Maybe it is just my ignorance about XDG_DATA_DIRS, but, wouldn't it be
more natural to use Emacs native mean of finding packages, akin to
Python's PYTHONPATH?  Emacs has the EMACSLOADPATH for this; per the
Emacs manual:

‘EMACSLOADPATH’
     A colon-separated list of directories(1) to search for Emacs Lisp
     files.  If set, it modifies the usual initial value of the
     ‘load-path’ variable (*note Lisp Libraries::).  An empty element
     stands for the default value of ‘load-path’; e.g., using
     ‘EMACSLOADPATH="/tmp:"’ adds ‘/tmp’ to the front of the default
     ‘load-path’.  To specify an empty element in the middle of the
     list, use 2 colons in a row, as in ‘EMACSLOADPATH="/tmp::/foo"’.

The neat thing about this is that we can use the native Guix mechanism
of 'search-paths', defined on the Emacs package, that would take care of
collecting all the Emacs Lisp packages used in a profile.

I had a working branch implementing this a long time ago; I could try
reviving it if you have an interested in it.  The one thing I didn't
like about it was I had to use a loose regexp in the path to accomodate
with the somewhat loose directory under which the libraries can be
installed (share/emacs/site-lisp vs
share/emacs/site-lisp/guix.d/package-name-version).

But it was working well, and allowed declaring a profile with emacs and
the wanted libraries, and having just these available within the
profile.

Maxim