Re: Custom themes and simple variables

[Chong Yidong <cyd@stupidchicken.com>]

Ralf Angeli <angeli@caeruleus.net> writes:

> There is a built-in list of viewers the user can choose from.  And this
> list is not supposed to be changed by the user.  Therefore it is
> declared with `defvar'.  (The user can add or overwrite viewers in a
> separate, customizable variable which is defined with `defcustom'.)
>
> The idea now is that the list of predefined viewers only contains
> viewers for the chosen platform.  Per default viewers available on
> GNU/Linux would be offered but if a theme for MiKTeX on Windows were
> enabled, only viewers available on Windows would be displayed.

Why not automatically detect the system type in the initialization form
for either the defvar'ed list of built-in viewers, or the defcustom
default for the user viewer?  I.e., either

(defvar available-viewers (cond (eq system-type 'gnu/linux) ....))

or

(defcustom my-viewer (cond (eq system-type 'gnu/linux) ....))

depending on whichever makes more sense for the particular situation.