unofficial mirror of help-gnu-emacs@gnu.org
 help / color / mirror / Atom feed
* multi-line conditionals in elisp
@ 2002-12-22 19:00 Michael Powe
  2002-12-22 19:12 ` David Kastrup
                   ` (2 more replies)
  0 siblings, 3 replies; 7+ messages in thread
From: Michael Powe @ 2002-12-22 19:00 UTC (permalink / raw)


hello,

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"))

this seems to work. (just putting an extra pair of parens around the
multiple statements did not work.  i guess that would be the
equivalent of {} in C.)  but i'm not sure if it's the best or only
way.  after all, if i have more than two items in the first part of
the conditional, that means stringing along multiple conds.  an
example would be mailcrypt, which in one of my .emacs has 7 line
items, setting and loading variables.  i dunno, it seems clumsy to me
because i'd be invoking the cond not because i'm interested in its
outcome per se, but just to force execution of the next statement.

thanks for any help.

mp

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.  and emacs is
still God's Own Editor(tm).  ;-)  Happy Holidays!

-- 
Michael Powe					Waterbury, CT
-------------------------------------------------------------
"The most likely way for the world to be destroyed, most experts
agree, is by accident.  That's where we come in.  We're computer
professionals.  We cause accidents."  -- Nathaniel Borenstein

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2002-12-24  3:17 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2002-12-22 19:00 multi-line conditionals in elisp Michael Powe
2002-12-22 19:12 ` David Kastrup
2002-12-22 22:48   ` Michael Powe
2002-12-22 23:05     ` David Kastrup
2002-12-24  3:17       ` Jesper Harder
     [not found] ` <michael+gnus@trollope.org>
2002-12-22 19:21   ` Peter S Galbraith
     [not found] ` <mailman.524.1040584903.19936.help-gnu-emacs@gnu.org>
2002-12-22 22:40   ` Michael Powe

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).