-;;; derived.el --- allow inheritance of major modes.
+;;; derived.el --- allow inheritance of major modes
;;; (formerly mode-clone.el)
;; Copyright (C) 1993, 1994, 1999 Free Software Foundation, Inc.
;; Author: David Megginson (dmeggins@aix1.uottawa.ca)
;; Maintainer: FSF
-;; Keywords: obsolete
+;; Keywords: extensions
;; This file is part of GNU Emacs.
\f
;;; Commentary:
-;; Obsolete.
-;; Use the `derived-major-mode' provided by easy-mmode.el instead.
-;; It is only kept for backward compatibility with byte-compiled files
-;; which refer to `derived-mode-init-mode-variables' and other functions.
-
-
-
;; GNU Emacs is already, in a sense, object oriented -- each object
;; (buffer) belongs to a class (major mode), and that class defines
;; the relationship between messages (input events) and methods
;;
;; will add a new major mode for HTML with very little fuss.
;;
-;; Note also the function `derived-mode-class,' which returns the non-derived
-;; major mode which a derived mode is based on (ie. NOT necessarily the
-;; immediate parent).
-;;
-;; (derived-mode-class 'text-mode) ==> text-mode
-;; (derived-mode-class 'hypertext-mode) ==> text-mode
-;; (derived-mode-class 'html-mode) ==> text-mode
+;; Note also the function `derived-mode-p' which can tell if the current
+;; mode derives from another. In a hypertext-mode, buffer, for example,
+;; (derived-mode-p 'text-mode) would return non-nil. This should always
+;; be used in place of (eq major-mode 'text-mode).
\f
;;; Code:
;; PUBLIC: define a new major mode which inherits from an existing one.
-;; ;;;###autoload
+;;;###autoload
(defmacro define-derived-mode (child parent name &optional docstring &rest body)
"Create a new mode as a variant of an existing mode.
Note that if the documentation string had been left out, it would have
been generated automatically, with a reference to the keymap."
- ; Some trickiness, since what
- ; appears to be the docstring
- ; may really be the first
- ; element of the body.
- (if (and docstring (not (stringp docstring)))
- (progn (setq body (cons docstring body))
- (setq docstring nil)))
- (setq docstring (or docstring (derived-mode-make-docstring parent child)))
-
- `(progn
- (derived-mode-init-mode-variables (quote ,child))
- (defun ,child ()
- ,docstring
- (interactive)
+ (when (and docstring (not (stringp docstring)))
+ ;; Some trickiness, since what appears to be the docstring may really be
+ ;; the first element of the body.
+ (push docstring body)
+ (setq docstring nil))
+
+ (unless parent (setq parent 'fundamental-mode))
+
+ (let ((map (derived-mode-map-name child))
+ (syntax (derived-mode-syntax-table-name child))
+ (abbrev (derived-mode-abbrev-table-name child))
+ (hook (derived-mode-hook-name child))
+ (docstring (derived-mode-make-docstring parent child docstring)))
+
+ `(progn
+ (defvar ,map (make-sparse-keymap))
+ (defvar ,syntax (make-char-table 'syntax-table nil))
+ (defvar ,abbrev)
+ (define-abbrev-table ',abbrev nil)
+ (put ',child 'derived-mode-parent ',parent)
+
+ (defun ,child ()
+ ,docstring
+ (interactive)
; Run the parent.
- (,parent)
+ ;; (combine-run-hooks
+
+ (,parent)
; Identify special modes.
- (if (get (quote ,parent) 'special)
- (put (quote ,child) 'special t))
+ (if (get (quote ,parent) 'special)
+ (put (quote ,child) 'special t))
; Identify the child mode.
- (setq major-mode (quote ,child))
- (setq mode-name ,name)
+ (setq major-mode (quote ,child))
+ (setq mode-name ,name)
; Set up maps and tables.
- (derived-mode-set-keymap (quote ,child))
- (derived-mode-set-syntax-table (quote ,child))
- (derived-mode-set-abbrev-table (quote ,child))
+ (unless (keymap-parent ,map)
+ (set-keymap-parent ,map (current-local-map)))
+ (let ((parent (char-table-parent ,syntax)))
+ (unless (and parent (not (eq parent (standard-syntax-table))))
+ (set-char-table-parent ,syntax (syntax-table))))
+ (when local-abbrev-table
+ (mapatoms
+ (lambda (symbol)
+ (or (intern-soft (symbol-name symbol) ,abbrev)
+ (define-abbrev ,abbrev (symbol-name symbol)
+ (symbol-value symbol) (symbol-function symbol))))
+ local-abbrev-table))
+
+ (use-local-map ,map)
+ (set-syntax-table ,syntax)
+ (setq local-abbrev-table ,abbrev)
; Splice in the body (if any).
- ,@body
-;;; ; Run the setup function, if
-;;; ; any -- this will soon be
-;;; ; obsolete.
-;;; (derived-mode-run-setup-function (quote ,child))
+ ,@body
+ ;; )
; Run the hooks, if any.
- (derived-mode-run-hooks (quote ,child)))))
+ (run-hooks ',hook)))))
+
+;; PUBLIC: find if the current mode derives from another.
+(defun derived-mode-p (&rest modes)
+ "Non-nil if the current major mode is derived from one of MODES.
+Uses the `derived-mode-parent' property of the symbol to trace backwards."
+ (let ((parent major-mode))
+ (while (and (not (memq parent modes))
+ (setq parent (get parent 'derived-mode-parent))))
+ parent))
;; PUBLIC: find the ultimate class of a derived mode.
(defun derived-mode-class (mode)
"Find the class of a major MODE.
A mode's class is the first ancestor which is NOT a derived mode.
-Use the `derived-mode-parent' property of the symbol to trace backwards."
+Use the `derived-mode-parent' property of the symbol to trace backwards.
+Since major-modes might derive from each other and from `fundamental-mode',
+this function is not very useful. Use `derived-mode-p' instead."
(while (get mode 'derived-mode-parent)
(setq mode (get mode 'derived-mode-parent)))
mode)
\f
-;; Inline functions to construct various names from a mode name.
-
-(defsubst derived-mode-setup-function-name (mode)
- "Construct a setup-function name based on a MODE name."
- (intern (concat (symbol-name mode) "-setup")))
+;;; PRIVATE
(defsubst derived-mode-hook-name (mode)
"Construct the mode hook name based on mode name MODE."
"Construct an abbrev-table name based on a MODE name."
(intern (concat (symbol-name mode) "-abbrev-table")))
+(defun derived-mode-make-docstring (parent child &optional docstring)
+ "Construct a docstring for a new mode if none is provided."
+
+ (let ((map (derived-mode-map-name child))
+ (syntax (derived-mode-syntax-table-name child))
+ (abbrev (derived-mode-abbrev-table-name child))
+ (hook (derived-mode-hook-name child)))
+
+ (unless (stringp docstring)
+ ;; Use a default docstring.
+ (setq docstring
+ (format "Major mode derived from `%s' by `define-derived-mode'.
+It inherits all of the parent's attributes, but has its own keymap,
+abbrev table and syntax table:
+
+ `%s', `%s' and `%s'
+
+which more-or-less shadow %s's corresponding tables."
+ parent map abbrev syntax parent)))
+
+ (unless (string-match (regexp-quote (symbol-name hook)) docstring)
+ ;; Make sure the docstring mentions the mode's hook
+ (setq docstring
+ (concat docstring
+ (if (eq parent 'fundamental-mode)
+ "\n\nThis mode "
+ (concat
+ "\n\nIn addition to any hooks its parent mode "
+ (if (string-match (regexp-quote (format "`%s'" parent))
+ docstring) nil
+ (format "`%s' " parent))
+ "might have run,\nthis mode "))
+ (format "runs the hook `%s'" hook)
+ ", as the final step\nduring initialization.")))
+
+ (unless (string-match "\\\\[{[]" docstring)
+ ;; And don't forget to put the mode's keymap
+ (setq docstring (concat docstring "\n\n\\{" (symbol-name map) "}")))
+
+ docstring))
+
+\f
+;;; OBSOLETE
+;; The functions below are only provided for backward compatibility with
+;; code byte-compiled with versions of derived.el prior to Emacs-21.
+
+(defsubst derived-mode-setup-function-name (mode)
+ "Construct a setup-function name based on a MODE name."
+ (intern (concat (symbol-name mode) "-setup")))
+
\f
;; Utility functions for defining a derived mode.
(define-abbrev-table (derived-mode-abbrev-table-name mode) nil)
(make-abbrev-table))
,(format "Abbrev table for %s." mode)))))
-
-(defun derived-mode-make-docstring (parent child)
- "Construct a docstring for a new mode if none is provided."
-
- (format "This major mode is a variant of `%s', created by `define-derived-mode'.
-It inherits all of the parent's attributes, but has its own keymap,
-abbrev table and syntax table:
-
- `%s-map' and `%s-syntax-table'
-
-which more-or-less shadow
-
- `%s-map' and `%s-syntax-table'
-
-\\{%s-map}" parent child child parent parent child))
-
\f
;; Utility functions for running a derived mode.
(defun derived-mode-run-hooks (mode)
"Run the mode hook for MODE."
-
(let ((hooks-name (derived-mode-hook-name mode)))
(if (boundp hooks-name)
(run-hooks hooks-name))))
HCoop / bpt / emacs.git / blobdiff