A Useful Hack for Xemacs

#### "Linux Gazette...making Linux just a little less scary! "

## A "Kill-Ring" Menu For Xemacs

#### by Larry Ayers

Copyright © 1996

##### Published in Issue 11 of the Linux Gazette

Lately I've been enjoying exploring the myriad capabilities of GNU Emacs' offspring and competitor, Xemacs. Aside from the burden of downloading the voluminous source, Xemacs offers quite a few features which Gnu Emacs lacks. Luckily for those considering a transition, the basic keystrokes and commands are nearly identical.

One feature of Gnu Emacs which I began to miss after a while was the handy pull-down menu which displays the first few words of each cut or copied selection made in the current session, i.e. the "kill-ring". The prospect of figuring out how the lisp files work which determine the menu-bar's structure wasn't too appealing. I know a little lisp, but not enough to add a new menu entry.

Some weeks later, while idly browsing through some emacs newsgroup headers, I came across this posting, which I'll quote here in full:

    In article <9604170740.AA26236@portia.uk.abs> imac@portia.rd.abs.alcatel.co.uk
    (Ian MacKinnon) writes:

    > When I used emacs (before I saw the light), I made use of a function
    > mouse-menu-choose-yank which offered you the choice to yank from the recent
    > history of selections via a popup menu, but I can't get it to work in
    > XEmacs because x-popup-menu doesn't exist, and the parameters to
    > popup-menu are different. Has anyone got an alternative. I enclose the
    > ...

    I have hacked the Emacs codes of mouse-menu-choose-yank to put in
    Xemacs as follows:

    (defvar yank-menu-length 40
      "*Maximum length of an item in the menu for select-and-yank.")
    (defun select-and-yank-filter (menu)
      (let* ((count 0))
        (append menu
                (mapcar
                 #'(lambda (str)
                     (if (> (length str) yank-menu-length)
                         (setq str (substring str 0 yank-menu-length)))
                     (prog1
                         (vector
                          str
                          (list
                           'progn
                           '(push-mark (point))
                           (list 'insert (list 'current-kill count t)))
                          t)
                       (setq count (1+ count))))
                 kill-ring))))

    For this to work, you have to put on your menu bar the following submenu
    (use add-submenu for that for example):

          ("Select and Yank"
           :included kill-ring
           :filter select-and-yank-filter)

    Hope this help

    -----------------------------------------------------------------------
    PHAM Dinh Tuan                         | e-mail: Dinh-Tuan.Pham@imag.fr
    Laboratoire de Modelisation et Calcul  | Tel: +33 76 51 44 23
    BP 53, 38041 Grenoble cedex (France)   | Fax: +33 76 63 12 63
    -----------------------------------------------------------------------

It took a little experimenting to get this to work. The first section of lisp code, ending with "kill-ring))))", can be copied unaltered into the xemacs section of your ~/.emacs file. If you're using Xemacs 19.14 (the current version), it goes into your ~/.xemacs-options file.

The second, shorter lisp snippet needs one small addition:

               (add-submenu nil '("Kill-Ring"
                         :included kill-ring
                         :filter select-and-yank-filter))

As well as adding the proper syntax for add-submenu, I shortened the menu-title, but it could be called anything you like.

When I first restarted Xemacs after placing this code into the init file the new submenu was nowhere to be seen. I surmised that I'd made some error, and put off further experimentation for another time. A few minutes later I was busily editing some file. I happened to glance up at the menu-bar and found a brand-new kill-ring submenu. Surprisingly the new menu only appears after a selection has been cut or copied.

I was happy, and thought that by relating my experience I could encourage other Xemacs users (especially the ones who know as little lisp as I do!) to try this neat hack. Thanks to Dinh Tuan Pham, if he or she should happen to see this.