(elisp)Library Headers


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Conventional Headers for Emacs Libraries
========================================

   Emacs 19 has conventions for using special comments in Lisp libraries
to divide them into sections and give information such as who wrote
them.  This section explains these conventions.  First, an example:

     ;;; lisp-mnt.el --- minor mode for Emacs Lisp maintainers
     
     ;; Copyright (C) 1992 Free Software Foundation, Inc.
     
     ;; Author: Eric S. Raymond <esr@snark.thyrsus.com>
     ;; Maintainer: Eric S. Raymond <esr@snark.thyrsus.com>
     ;; Created: 14 Jul 1992
     ;; Version: 1.2
     ;; Keywords: docs
     
     ;; This file is part of GNU Emacs.
     COPYING CONDITIONS...

   The very first line should have this format:

     ;;; FILENAME --- DESCRIPTION

The description should be complete in one line.

   After the copyright notice come several "header comment" lines, each
beginning with `;;; HEADER-NAME:'.  Here is a table of the conventional
possibilities for HEADER-NAME:

`Author'
     This line states the name and net address of at least the principal
     author of the library.

     If there are multiple authors, you can list them on continuation
     lines led by `;;<TAB>', like this:

          ;; Author: Ashwin Ram <Ram-Ashwin@cs.yale.edu>
          ;;	Dave Sill <de5@ornl.gov>
          ;;	Dave Brennan <brennan@hal.com>
          ;;	Eric Raymond <esr@snark.thyrsus.com>

`Maintainer'
     This line should contain a single name/address as in the Author
     line, or an address only, or the string "FSF".  If there is no
     maintainer line, the person(s) in the Author field are presumed to
     be the maintainers.  The example above is mildly bogus because the
     maintainer line is redundant.

     The idea behind the `Author' and `Maintainer' lines is to make
     possible a Lisp function to "send mail to the maintainer" without
     having to mine the name out by hand.

     Be sure to surround the network address with `<...>' if you
     include the person's full name as well as the network address.

`Created'
     This optional line gives the original creation date of the file.
     For historical interest only.

`Version'
     If you wish to record version numbers for the individual Lisp
     program, put them in this line.

`Adapted-By'
     In this header line, place the name of the person who adapted the
     library for installation (to make it fit the style conventions, for
     example).

`Keywords'
     This line lists keywords for the `finder-by-keyword' help command.
     This field is important; it's how people will find your package
     when they're looking for things by topic area.

   Just about every Lisp library ought to have the `Author' and
`Keywords' header comment lines.  Use the others if they are
appropriate.  You can also put in header lines with other header
names--they have no standard meanings, so they can't do any harm.

   We use additional stylized comments to subdivide the contents of the
library file.  Here is a table of them:

`;;; Commentary:'
     This begins introductory comments that explain how the library
     works.  It should come right after the copying permissions.

`;;; Change log:'
     This begins change log information stored in the library file (if
     you store the change history there).  For most of the Lisp files
     distributed with Emacs, the change history is kept in the file
     `ChangeLog' and not in the source file at all; these files do not
     have a `;;; Change log:' line.

`;;; Code:'
     This begins the actual code of the program.

`;;; FILENAME ends here'
     This is the "footer line"; it appears at the very end of the file.
     Its purpose is to enable people to detect truncated versions of
     the file from the lack of a footer line.


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