Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bbn!jr@bbn.com
From: jr@bbn.com (John Robinson)
Newsgroups: comp.emacs
Subject: Re: How to define VT2xx or VT3xx function keys in .emacs file?
Message-ID: <36802@bbn.COM>
Date: 6 Mar 89 16:23:58 GMT
References: <36761@bbn.COM>
Sender: news@bbn.COM
Reply-To: jr@bbn.com (John Robinson)
Organization: BBN Systems and Technologies Corporation, Cambridge MA
Lines: 82
In-reply-to: DHASKIN@CLARKU.BITNET

In article <36761@bbn.COM>, DHASKIN@CLARKU writes:
>Okay, I *know* this can be done, and I'm apparently missing something
>obvious.  I would like Emacs to start up with the Do key define as M-x
>and Insert Here defined as yank.  I have no problem doing it once I'm
>*in* Emacs, with either global-set-key or:
>
>        (define-key esc-map "[26~" 'execute-extended-command)
>
>but when I put the above line in my .emacs file, I get an "Error in Init
>File" or some such thing when Emacs starts up.  (BTW, I know that [26~ may
>not be *quite* the sequence, but y'know what I mean).
>
>Is this the right direction?  Or does it involve the CSI-map?  I feel sort of
>foolish, it should be easy.  But then again, I do recall a discussion a
>few months ago about what one could and couldn't do in a .emacs file.

I believe this is because the key bindings at the time your .emacs
file is executed are simply the defaults.  ESC-[ starts off bound to
backward-paragraph, and so can't be the prefix of a longer command
string.

After it has finished you .emacs, emacs reads terminal-specific
initialization from the file ..emacs/lisp/term/vt200.el (assuming your
TERM variable is "vt200"), which will set things so that ESC-[ is a
prefix.  Here's how that happens:

  (global-set-key "\e[" CSI-map)

Once ESC-[ is bound to a keymap, things are fine.  This won't happen
until you call the function (enable-arrow-keys).  Look in vt200.el for
more information on what happens at startup.

Now, since vt200.el is normally read *after* your .emacs, you can't
modify bindings that depend on its keymap settings.  However, there is
a way:

  term-setup-hook's value is nil

  Documentation:
  Function to be called after loading terminal-specific lisp code.
  It is called with no arguments.  You can use this to override the
  definitions made by the terminal-specific file.

You could do something like this in your .emacs:

  (defun my-vt200-init ()
    "Enable the VT200 function keys and bind the Do key"

    (enable-arrow-keys)
    (define-key esc-map "[26~" 'execute-extended-command))

  (setq term-setup-hook 'my-vt200-init)

[Programming style aside: this ought to be careful not to trample an
existing term-setup-hook; to be really cute it should append to the
hook, avoiding signing itself up twice by scanning the list first.
There oughta be a package to help with this...any volunteers?]

Rather than define-key, you should use global-set-key:

  (global-set-key "\e[26~" 'execute-extended-command)

This avoids having to know the name of esc-map, which just could
change under you some day.

Having said all this, there is another way that ought to work in your
.emacs file:

  (require 'keypad)
  (keypad-default "x" 'execute-etended-command)

The beauty of this is that it will work across all terminals that have
a "Do" key, and avoids the hassle of the term-setup-hook.  Details in
lisp/keypad.el.

Let me also echo the complaints about the un-help-ful-ness [that's
kind-er-and-gen-tle-er speak] of "Error in Init file"!

p.s. to Kyle Jones: another one for the frequent questions file?
--
/jr
jr@bbn.com or bbn!jr