Re: multi-line conditionals in elisp

[David Kastrup <David.Kastrup@t-online.de>]

Michael Powe <michael+gnus@trollope.org> writes:

> sorry for the dumb question, but i'm sure of the best way to do
> this. i have emacs installed on several machines and would like to use
> a single .emacs.  it's annoying to have to maintain different ones,
> and i forget sometimes that one library is installed on one machine
> but not on another.
> 
> my solution was to put a conditional in the .emacs to test for the
> existence of a library before following its loading instructions.
> what i'm having a problem with, is conditionals of this format:
> 
> if (true)
>   do item one
>   do item two
>   do item three
>   ...
> else
>   do item four
> 
> this is trivial in other languages, but not, it seems, in elisp.  (i
> think it's just a case of, i don't really understand the language.)
> here's what i did:
> 
> (if (locate-library "python-mode")
>     (cond((autoload 'python-mode "python-mode" "Python editing mode" t)
> 	  (setq auto-mode-alist
> 		(cons '("\\.py$" . python-mode) auto-mode-alist))))
>   (message "python library not found"))

That is junk.  I recommend you look up progn.

> nb. trivial note: on my main workstation, i maintain my dot-files in
> rcs.  i noted yesterday that my oldest entry in the .emacs is from
> january 30, 1998.  so, in a little over a month, it will be 5 years
> old.  that's a lot of bits & bytes through the pipe.

5 years and you don't know progn.  That certainly _is_ impressive.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum