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Emacs.3pm

NAME

Emacs - Redefine Perl's system primitives to work inside of Emacs

SYNOPSIS

     perlmacs -w -MEmacs -e main -- --display :0.0 file.txt
 
 

     #! /usr/bin/perlmacs
     use Emacs;
     use Emacs::Lisp;
     setq { $mail_self_blind = t; };
     exit main ($0, "-q", @ARGV);
 
 

DESCRIPTION

This module replaces "STDIN", "STDOUT", "STDERR", %ENV, %SIG, "exit", and "warn" (via $SIG{__WARN__}) with versions that work safely within an Emacs session. In Perlmacs, it also defines a function named main, which launches an Emacs editing session from within a script.

STDIN

Reading a line from Perl's "STDIN" filehandle causes a string to be read from the minibuffer with the prompt "Enter input: ". To show a different prompt, use:

     $string = &read_string ("Prompt: ");
 
 

STDOUT

Printing to Perl's "STDOUT" filehandle inserts text into the current buffer as though typed, unless you have changed the Lisp variable "standard-output" to do something different.

STDERR and `warn'

Perl's "warn" operator and "STDERR" filehandle are redirected to the minibuffer.

%ENV

Access to %ENV is redirected to the Lisp variable "process-environment".

%SIG

Setting signal handlers is not currently permitted under Emacs.

exit

"exit" calls "kill-emacs".

main (CMDLINE)

When you "use Emacs" in a perlmacs script, a Perl sub named "main" may be used to invoke the Emacs editor. This makes it possible to put customization code, which would normally appear as Lisp in ~/.emacs, into a Perl script.

NOTE: This function does not work under EPL. You have to have Perlmacs to use it. See ``EPL AND PERLMACS'' in Emacs::Lisp.

For example, this startup code

     (setq
      user-mail-address "gnaeus@perl.moc"
      mail-self-blind t
      mail-yank-prefix "> "
      )
 
 

     (put 'eval-expression 'disabled nil)
 
 

     (global-font-lock-mode 1 t)
     (set-face-background 'highlight "maroon")
     (set-face-background 'region "Sienna")
 
 

could be placed in a file with the following contents:

     #! /usr/local/bin/perlmacs
 
 

     use Emacs;
     use Emacs::Lisp;
 
 

     setq {
         $user_mail_address = 'gnaeus@perl.moc';
         $mail_self_blind = t;
         $mail_yank_prefix = '> ';
         $eval_expression{\*disabled} = undef;
     };
 
 

     &global_font_lock_mode(1, t);
     &set_face_background(\*highlight, "maroon");
     &set_face_background(\*region, "Sienna");
 
 

     exit main($0, "-q", @ARGV);
 
 

When you wanted to run Emacs, you would invoke this program.

The arguments to "main" correspond to the "argv" of the "main" function in a C program. The first argument should be the program's invocation name, as in this example. -q inhibits running ~/.emacs (which is the point, after all).

BUGS

* Problems with `main'.

"main()" doesn't work under EPL. It may open an X display and not close it. Those are the most obvious of many problems with "main".

The thing is, Emacs was not written with the expectation of being embedded in another program, least of all a language interpreter such as Perl. Therefore, when Emacs is told to exit, it believes the process is really about to exit, and it neglects to tidy up after itself.

For best results, the value returned by "main" should be passed to Perl's "exit" soon, as in this code:

     exit (main($0, @args));
 
 

COPYRIGHT

Copyright (C) 1998-2001 by John Tobey, jtobey@john-edwin-tobey.org. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
 
 

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.
 
 

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING.  If not, write to the
   Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
   MA 02111-1307  USA
 
 

SEE ALSO

perl, Emacs::Lisp, emacs.