The Custom Library

The Custom Library is intended for use by emacs lisp programmers who want to make their emacs packages easily customizable. It allows the programmer to

declare the type for each user option, i.e. specify the set of legal values for each variable,
specify and initialize the faces used by the package, and
organize the user options into groups and hierarchies.

The user will then be able to customize the user options through a helpful structured interface that resembles the property editor in modern GUI programs.

Together with Emacs W3 3.0.51 or later, it also allows people to write interactive goal oriented tutorials for customizing. A demonstration is available. It works best after Gnus is loaded.

Version: 1.9962

This is the last unbundled version. You should normally use the version distributed with Emacs or XEmacs, which will be newer that this. If you have XEmacs 19.14, XEmacs 20.0 or Emacs 19.34 or earlier, you emacs will not have a usable version of custom bundled. This version may or may not work for you. It should work for Emacs 19.34 at least. It will not work with Emacs 20.1 or XEmacs 20.3.

download the library. This includes the widget library described below.
Read the manual.

Warning: This version conflicts with Gnus versions prior to Red Gnus 0.36. If you want to use both the Custom Library and Gnus, please upgrade.

If you write software that must work without the new custom, you can use this hack stolen from w3-cus.el:

(eval-and-compile
  (condition-case ()
      (require 'custom)
    (error nil))
  (if (and (featurep 'custom) (fboundp 'custom-declare-variable))
      nil ;; We've got what we needed
    ;; We have the old custom-library, hack around it!
    (defmacro defgroup (&rest args)
      nil)
    (defmacro defface (var values doc &rest args)
       (` (make-face (, var))))
    (defmacro defcustom (var value doc &rest args) 
      (` (defvar (, var) (, value) (, doc))))))

History

A prototype of the Custom Library was used by Gnus 5.0 to 5.3 and included in corresponding Emacs distributions. It did demonstrate the user interface, but lacked a proper API. Please avoid using this old version in your software, the new incompatible version is much better, and is used in Gnus 5.4 and bundled with Emacs in the future.

There is some old documentation available, which was written before the widget library and is obsolete now, but still demonstrates the basic design of the new library.

You can find some older versions at the main ftp directory.

The Emacs Widget Library

Version: 1.9962

The Emacs Widget Library implements the kind of user interface components usually found in GUI toolkits within emacs. It is used by at least two other packages, and is getting close to release quality. The code is should work with Emacs 19.30 and later, and will work with XEmacs 19.14 thanks to William Perry <wmperry@cs.indiana.edu>.

As with custom, this version will not work with Emacs 20.1, XEmacs 20.3, or anything newer than that. The widget version bundled with these emacs versions will be newer that this.

See an example buffer containing all the widgets.
See the code for implementing the example buffer.
download the library. If you download the custom library, you will not need to download this file too.
Read the manual.

Contact Info

Bug reports for the widget and custom version bundled with emacs should go to <bug-gnu-emacs@prep.ai.mit.edu> and <xemacs@xemacs.org> respectively.

Per Abrahamsen <abraham@dina.kvl.dk>