Re: External programs and resources

["Lennart Borgman" <lennart.borgman.073@student.lu.se>]

----- Original Message ----- 
From: "Stefan Monnier" <monnier@iro.umontreal.ca>


> > I have not been able to find a common entrypoint for external resources
from
> > Emacs. I would for example appreciate if there was only one place where
the
> > path to a program like Ghostview was entered.
>
> > I would suggest that customization of things like this should be in one
or
> > several lisp modules that could be used by other modules.
>
> It might be a good idea, but since packages are developed separately by
> manny people who don't know each other, it's not always so easy
(especially
> because you also still want to be able to specify different values
> sometimes, because you might sometimes want to use one version of `gv' for
> one package and another for some other package).

Maybe this can be resolved rather easily, at least in principle. The
organisation could perhaps be like this:

- A common elisp module (ext-prog.el?) where for each external program used
by emacs there is a "defcustom" variable for its path. If not set this could
be initialized by executable-find perhaps.

- If a lisp module is using an external program listed in "ext-prog.el" it
can use the corresponding variable.

- If this module however want to give the possibility to use another version
of the program than the one pointed to by the "ext-prog.el" variable it can
define a function that uses a NON-"defcustom" variable defined in this
package
if it is set, otherwise the "ext-prog.el" variable. (I think it would be
confusing to have the second, module-specific variable defcustom too.)

- A customization group, maybe named "external-programs"?

> In the short term, the best we can do is find those redundant
customizations
> and unify them.  Which ones were you thinking of?

At the moment I was only thinking of Ghostview and it relatives.

- Lennart