+;;; easy-mmode.el --- easy definition of minor modes.
+;; Copyright (C) 1997 Free Software Foundation, Inc.
+;; Author: Georges Brun-Cottan <Georges.Brun-Cottan@inria.fr>
+;; This file is part of GNU Emacs.
+;; GNU Emacs 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, or (at your option)
+;; GNU Emacs 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 GNU Emacs; see the file COPYING. If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+;; Minor modes are useful and common. This package makes defining a
+;; minor mode easy, by focusing on the writing of the minor mode
+;; functionalities themselves. Moreover, this package enforces a
+;; conventional naming of user interface primitives, making things
+;; natural for the minor-mode end-users.
+;; For each mode, easy-mmode defines the following:
+;; <mode> : The minor mode predicate. A buffer-local variable.
+;; <mode>-map : The keymap possibly associated to <mode>.
+;; <mode>-hook,<mode>-on-hook,<mode>-off-hook and <mode>-mode:
+;; see `easy-mmode-define-minor-mode' documentation
+;; (pp (macroexpand '(easy-mmode-define-minor-mode <your-mode> <doc>)))
+;; to check the result before using it.
+;; The order in which minor modes are installed is important. Keymap
+;; lookup proceeds down minor-mode-map-alist, and the order there
+;; tends to be the reverse of the order in which the modes were
+;; installed. Perhaps there should be a feature to let you specify
+(defun easy-mmode-define-keymap (keymap-alist &optional menu-name)
+ "Return a keymap built from KEYMAP-ALIST.
+KEYMAP-ALIST must be a list of (KEYBINDING . BINDING) where
+KEYBINDING and BINDINGS are suited as for define-key.
+optional MENU-NAME is passed to `make-sparse-keymap'."
+ (let ((keymap (make-sparse-keymap menu-name)))
+ (function (lambda (bind)
+ (car bind) (cdr bind))))
+(defmacro easy-mmode-define-toggle (mode &optional doc)
+ "Define a one arg toggle mode MODE function and associated hooks.
+MODE-mode is the so defined function that toggle the mode.
+optional DOC is its associated documentation.
+Hooks are checked for run, each time MODE-mode is called.
+They run under the followings conditions:
+MODE-hook: if the mode is toggled.
+MODE-on-hook: if the mode is on.
+MODE-off-hook: if the mode is off.
+When the mode is effectively toggled, two hooks may run.
+If so MODE-hook is guaranteed to be the first.
+\(defmacro easy-mmode-define-toggle (MODE &optional DOC)"
+ (if (string-match "-mode\\'" (symbol-name mode))
+ (concat (symbol-name mode) "-mode")))
+ (hook (intern (concat mode-name "-hook")))
+ (hook-on (intern (concat mode-name "-on-hook")))
+ (hook-off (intern (concat mode-name "-off-hook")))
+ (toggle (intern mode-name))
+ (format "With no argument, toggle %s mode.
+With zero or negative arg turn mode off"
+ ,(format "Hook called when %s mode is toggled" mode-name))
+ ,(format "Hook called when %s mode is turned on" mode-name))
+ ,(format "Hook called when %s mode is turned off" mode-name))
+ (defun ,toggle (&optional arg)
+ (let ((old-mode ,mode))
+ (or (listp arg);; C-u alone
+ (> (prefix-numeric-value arg) 0))
+ (not (equal old-mode ,mode))
+ (run-hooks ',hook-off)))))))
+(defmacro easy-mmode-define-minor-mode (mode doc &optional init-value lighter keymap)
+ "Define a new minor mode MODE.
+This function defines the associated control variable, keymap,
+toggle command, and hooks (see `easy-mmode-define-toggle').
+DOC is the documentation for the mode toggle command.
+Optional LIGHTER is displayed in the mode-bar when the mode is on.
+Optional KEYMAP is the default (defvar) keymap bound to the mode keymap.
+If it is a list, it is passed to `easy-mmode-define-keymap'
+in order to build a valid keymap.
+ (MODE DOC &optional INIT-VALUE LIGHTER KEYMAP)...\)"
+ (let* ((mode-name (symbol-name mode))
+ (mode-doc (format "Non-nil if %s mode is enabled." mode-name))
+ (keymap-name (concat mode-name "-map"))
+ (keymap-doc (format "Keymap for %s mode." mode-name)))
+ (defvar ,mode ,init-value ,mode-doc)
+ (make-variable-buffer-local ',mode)
+ ;; define the minor-mode keymap
+ (defvar ,(intern keymap-name)
+ (cond ((and ,keymap (keymapp ,keymap))
+ (easy-mmode-define-keymap ,keymap))
+ (t (error "Invalid keymap %S" ,keymap)))
+ ;; define the toggle and the hooks
+ ,(macroexpand `(easy-mmode-define-toggle ,mode ,doc)) ; toggle and hooks
+ (or (assq ',mode minor-mode-alist)
+ (cons (list ',mode ,lighter) minor-mode-alist)))
+ ;; update the minor-mode-map
+ (or (assq ',mode minor-mode-map-alist)
+ (setq minor-mode-map-alist
+ (cons (cons ',mode ,(intern keymap-name)) minor-mode-map-alist)))) ))
+;;; easy-mmode.el ends here