Re: syntax / method for executing an emacs lisp function?

[Kevin Rodgers <ihs_4664@yahoo.com>]

farbot@gmail.com wrote:
> I'm writing a language mode for emacs, but have never used emacs before
> (the mode is for others to use).  I've searched for hours, but can't
> find the incantation I need.  I'd appreciate some pointers to specific
> help files or techniques.

First, you should read the Introduction to Programming in Emacs Lisp,
which is a manual distributed with Emacs 22 in Info format and available
on the web at http://www.gnu.org/software/emacs/emacs-lisp-intro/

The Emacs Lisp reference manual is distributed with Emacs in Info
format, too.  `C-h i' then `m Info RET' will get you started with
Info, or read it online at http://www.gnu.org/software/emacs/elisp/

The Emacs Wiki is a great resource; here are two good pages, one general
and one specific:

http://www.emacswiki.org/cgi-bin/wiki/CategoryCode
http://www.emacswiki.org/cgi-bin/wiki/CreateNewMajorMode

> I'd like to run the regexp-opt command to optimize my list of keywords.
>  For example:
> (regexp-opt '("TRUE" "FALSE") t)
> 
> I've tried a bunch of methods from inside emacs, but it always says
> there is "no match" for regexp-opt.

regexp-opt is autoloaded in Emacs 22, but perhaps you need this:
(require 'regexp-opt)

> I've had the best luck on the
> command line using 'emacs --eval' option, but one of two things
> happens: 1) it dislikes my syntax (badly placed ()s, unmatched '), or
> 2) it accepts the syntax, and opens emacs and shows a *scratch* buffer
> in "(Lisp Interaction)" mode -- but there are no function results
> present.  In the *Messages* buffer, I find my command echoed, but still
> no function results.

Please post exactly what you did, and exactly what happened.  My
crystal ball is at the shop.

The results of a function call given on the command line with --eval
are not printed anywhere by default.

> I also tried typing commands in Lisp Interaction mode -- but neither
> return nor enter makes them execute.

That's because RET is bound to newline in that mode.  You need to
type C-j, which runs eval-print-last-sexp.

This is documented in the Emacs manual in the Lisp Interaction node.

> I'm thinking I need to figure out how to execute from a file instead of
> the command line -- since some of my keyword lists are quite long (not
> sure how much fits on the command line).

That's up to your shell and your OS.  But putting your Emacs Lisp in
its own file is a good idea anyway.

> I'm running emacs 21.2.1 from the command line on Mac OS X 10.4.6.
> Thanks for any pointers you might have.

Read the Fine Manuals.

-- 
Kevin