Re: What's the right way to define a custom info path.

[Eli Zaretskii <eliz@gnu.org>]

> From: Pierre Téchoueyres <pierre.techoueyres@free.fr>
> Date: Wed, 25 Nov 2015 20:54:25 +0100
> 
> > No, there's no bug here, AFAICT.  If you want to set up
> > Info-directory-list or Info-additional-directory-list, you must load
> > info.elc first.  (But again, I don't recommend going that way.)
> 
> But these two variables could be modified with the custom machinery, and so 
> without requiring info[.elc] aren't they ?

Yes, you could do that.  But I interpreted your message as a request
to set them up in Lisp, not via Custom.

> But I understand your advice that doing that is discouraged.

No, it's not discouraged.  It just is harder to set up correctly,
whereas the semantics of INFOPATH is simple.

> Second, the default value for Info-default-directory-list (as computed by 
> the defcustom in info.el) is ("%emacs_dir/info") on my windows install. Is 
> this the expected behaviour ?

Yes.  That value is never used.

> this value is obviously overridden by info-
> initialize and become, in my install, ("c:/programmes/emacs/info").
> Again is this the expected behaviour ?

Yes.

> Third, in the windows patform (substitute-env-vars "%emacs_dir%") doesn't 
> produce "c:/programmes/emacs" as I expected. But (substitute-env-vars 
> "$emacs_dir") do the expansion. Is this the expected behaviour ?

Yes.  substitute-env-vars supports the Unix style of environment
variables.

> Is it that we should not offer a version that performs primary
> processing ?

We could, but why bother?  When info loads, it recomputes the value
according to where Emacs was installed.