X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/56152e17443b1bc1fa1774693dfa3ea4c73fa413..3c53a3cf83c218772d9bcfde4cd60c1face33e93:/lisp/derived.el

diff --git a/lisp/derived.el b/lisp/derived.el
index 83b114c0f1..3586affe21 100644
--- a/lisp/derived.el
+++ b/lisp/derived.el
@@ -1,10 +1,11 @@
-;;; derived.el -- allow inheritance of major modes.
+;;; derived.el --- allow inheritance of major modes
 ;;; (formerly mode-clone.el)
 
-;; Copyright (C) 1993, 1994 Free Software Foundation, Inc.
+;; Copyright (C) 1993, 1994, 1999 Free Software Foundation, Inc.
 
 ;; Author: David Megginson (dmeggins@aix1.uottawa.ca)
 ;; Maintainer: FSF
+;; Keywords: extensions
 
 ;; This file is part of GNU Emacs.
 
@@ -19,8 +20,9 @@
 ;; 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, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; 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.
 
 ;;; Commentary:
 
@@ -69,12 +71,6 @@
 ;; - assign the value 'hypertext-mode' to the 'major-mode' variable
 ;; - run the body of commands provided in the macro -- in this case,
 ;;   set the local variable `case-fold-search' to nil.
-;; - **run the command (hypertext-mode-setup), which is empty by
-;;   default, but may be redefined by the user to contain special
-;;   commands (ie. setting local variables like 'outline-regexp')
-;;   **NOTE: do not use this option -- it will soon be obsolete.
-;; - run anything assigned to 'hypertext-mode-hooks' (obsolete, but
-;;   supported for the sake of compatibility).
 ;;
 ;; The advantages of this system are threefold.  First, text mode is
 ;; untouched -- if you had added the new keystroke to `text-mode-map,'
@@ -85,19 +81,34 @@
 ;;
 ;;   (define-derived-mode html-mode hypertext-mode "HTML")
 ;;   [various key definitions]
-;; 
-;; 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).
+;; will add a new major mode for HTML with very little fuss.
 ;;
-;; (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).
 
 ;;; Code:
 
+;;; PRIVATE: defsubst must be defined before they are first used
+
+(defsubst derived-mode-hook-name (mode)
+  "Construct the mode hook name based on mode name MODE."
+  (intern (concat (symbol-name mode) "-hook")))
+
+(defsubst derived-mode-map-name (mode)
+  "Construct a map name based on a MODE name."
+  (intern (concat (symbol-name mode) "-map")))
+
+(defsubst derived-mode-syntax-table-name (mode)
+  "Construct a syntax-table name based on a MODE name."
+  (intern (concat (symbol-name mode) "-syntax-table")))
+
+(defsubst derived-mode-abbrev-table-name (mode)
+  "Construct an abbrev-table name based on a MODE name."
+  (intern (concat (symbol-name mode) "-abbrev-table")))
+
 ;; PUBLIC: define a new major mode which inherits from an existing one.
 
 ;;;###autoload
@@ -106,13 +117,14 @@
 
 The arguments to this command are as follow:
 
-PARENT:    the name of the command for the parent mode (ie. text-mode).
 CHILD:     the name of the command for the derived mode.
-NAME:      a string which will appear in the status line (ie. \"Hypertext\")
+PARENT:    the name of the command for the parent mode (e.g. `text-mode')
+           or nil if there is no parent.
+NAME:      a string which will appear in the status line (e.g. \"Hypertext\")
 DOCSTRING: an optional documentation string--if you do not supply one,
            the function will attempt to invent something useful.
 BODY:      forms to execute just before running the
-           hooks for the new mode.
+           hooks for the new mode.  Do not use `interactive' here.
 
 Here is how you could define LaTeX-Thesis mode as a variant of LaTeX mode:
 
@@ -122,7 +134,7 @@ You could then make new key bindings for `LaTeX-thesis-mode-map'
 without changing regular LaTeX mode.  In this example, BODY is empty,
 and DOCSTRING is generated by default.
 
-On a more complicated level, the following command uses sgml-mode as
+On a more complicated level, the following command uses `sgml-mode' as
 the parent, and then sets the variable `case-fold-search' to nil:
 
   (define-derived-mode article-mode sgml-mode \"Article\"
@@ -132,136 +144,183 @@ the parent, and then sets the variable `case-fold-search' to nil:
 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)
+  (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))
+
+  (when (eq parent 'fundamental-mode) (setq parent nil))
+
+  (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-syntax-table))
+       (defvar ,abbrev
+	 (progn (define-abbrev-table ',abbrev nil) ,abbrev))
+       (put ',child 'derived-mode-parent ',parent)
+
+       (defun ,child ()
+	 ,docstring
 	 (interactive)
 					; Run the parent.
-	 ((, parent))
-					; Identify special modes.
-	 (if (get (quote (, parent)) 'special)
-	     (put (quote (, child)) 'special t))
+	 (delay-mode-hooks
+
+	  (,(or parent 'kill-all-local-variables))
 					; Identify the child mode.
-	 (setq major-mode (quote (, child)))
-	 (setq mode-name (, name))
+	  (setq major-mode (quote ,child))
+	  (setq mode-name ,name)
+					; Identify special modes.
+	  ,(when parent
+	     `(progn
+		(if (get (quote ,parent) 'special)
+		    (put (quote ,child) 'special t))
 					; 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-mode-hooks ',hook)))))
 
 ;; PUBLIC: find the ultimate class of a derived mode.
 
 (defun derived-mode-class (mode)
-  "Find the class of a major 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)
 
 
-;; Inline functions to construct various names from a mode name.
+;;; PRIVATE
 
-(defsubst derived-mode-setup-function-name (mode)
-  "Construct a setup-function name based on a mode name."
-  (intern (concat (symbol-name mode) "-setup")))
+(defun derived-mode-make-docstring (parent child &optional docstring)
+  "Construct a docstring for a new mode if none is provided."
 
-(defsubst derived-mode-hooks-name (mode)
-  "Construct a hooks name based on a mode name."
-  (intern (concat (symbol-name mode) "-hooks")))
+  (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
+	    (if (null parent)
+		(format "Major-mode.
+Uses keymap `%s', abbrev table `%s' and syntax-table `%s'." map abbrev syntax)
+	      (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:
 
-(defsubst derived-mode-map-name (mode)
-  "Construct a map name based on a mode name."
-  (intern (concat (symbol-name mode) "-map")))
+  `%s', `%s' and `%s'
 
-(defsubst derived-mode-syntax-table-name (mode)
-  "Construct a syntax-table name based on a mode name."
-  (intern (concat (symbol-name mode) "-syntax-table")))
+which more-or-less shadow %s's corresponding tables."
+		      parent map abbrev syntax parent))))
 
-(defsubst derived-mode-abbrev-table-name (mode)
-  "Construct an abbrev-table name based on a mode name."
-  (intern (concat (symbol-name mode) "-abbrev-table")))
+    (unless (string-match (regexp-quote (symbol-name hook)) docstring)
+      ;; Make sure the docstring mentions the mode's hook
+      (setq docstring
+	    (concat docstring
+		    (if (null parent)
+			"\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))
+
+
+;;; 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")))
 
 
 ;; Utility functions for defining a derived mode.
 
 ;;;###autoload
 (defun derived-mode-init-mode-variables (mode)
-  "Initialise variables for a new mode. 
+  "Initialise variables for a new MODE.
 Right now, if they don't already exist, set up a blank keymap, an
 empty syntax table, and an empty abbrev table -- these will be merged
 the first time the mode is used."
 
   (if (boundp (derived-mode-map-name mode))
       t
-    (eval (` (defvar (, (derived-mode-map-name mode)) 
+    (eval `(defvar ,(derived-mode-map-name mode)
 	       (make-sparse-keymap)
-	       (, (format "Keymap for %s." mode)))))
+	       ,(format "Keymap for %s." mode)))
     (put (derived-mode-map-name mode) 'derived-mode-unmerged t))
 
   (if (boundp (derived-mode-syntax-table-name mode))
       t
-    (eval (` (defvar (, (derived-mode-syntax-table-name mode))
-	       (make-vector 256 nil)
-	       (, (format "Syntax table for %s." mode)))))
+    (eval `(defvar ,(derived-mode-syntax-table-name mode)
+	     ;; Make a syntax table which doesn't specify anything
+	     ;; for any char.  Valid data will be merged in by
+	     ;; derived-mode-merge-syntax-tables.
+	     (make-char-table 'syntax-table nil)
+	     ,(format "Syntax table for %s." mode)))
     (put (derived-mode-syntax-table-name mode) 'derived-mode-unmerged t))
 
   (if (boundp (derived-mode-abbrev-table-name mode))
       t
-    (eval (` (defvar (, (derived-mode-abbrev-table-name mode))
-	       (progn (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))
-
+    (eval `(defvar ,(derived-mode-abbrev-table-name mode)
+	     (progn
+	       (define-abbrev-table (derived-mode-abbrev-table-name mode) nil)
+	       (make-abbrev-table))
+	     ,(format "Abbrev table for %s." mode)))))
 
 ;; Utility functions for running a derived mode.
 
 (defun derived-mode-set-keymap (mode)
-  "Set the keymap of the new mode, maybe merging with the parent."
+  "Set the keymap of the new MODE, maybe merging with the parent."
   (let* ((map-name (derived-mode-map-name mode))
 	 (new-map (eval map-name))
 	 (old-map (current-local-map)))
-    (if (get map-name 'derived-mode-unmerged)
-	(derived-mode-merge-keymaps old-map new-map))
+    (and old-map
+	 (get map-name 'derived-mode-unmerged)
+	 (derived-mode-merge-keymaps old-map new-map))
     (put map-name 'derived-mode-unmerged nil)
     (use-local-map new-map)))
 
-(defun derived-mode-set-syntax-table (mode) 
-  "Set the syntax table of the new mode, maybe merging with the parent."
+(defun derived-mode-set-syntax-table (mode)
+  "Set the syntax table of the new MODE, maybe merging with the parent."
   (let* ((table-name (derived-mode-syntax-table-name mode))
 	 (old-table (syntax-table))
 	 (new-table (eval table-name)))
@@ -271,7 +330,7 @@ which more-or-less shadow
     (set-syntax-table new-table)))
 
 (defun derived-mode-set-abbrev-table (mode)
-  "Set the abbrev table if it exists.  
+  "Set the abbrev table for MODE if it exists.
 Always merge its parent into it, since the merge is non-destructive."
   (let* ((table-name (derived-mode-abbrev-table-name mode))
 	 (old-table local-abbrev-table)
@@ -287,29 +346,46 @@ Always merge its parent into it, since the merge is non-destructive."
 ;;;	(funcall fname))))
 
 (defun derived-mode-run-hooks (mode)
-  "Run the hooks if they exist."
-
-  (let ((hooks-name (derived-mode-hooks-name mode)))
+  "Run the mode hook for MODE."
+  (let ((hooks-name (derived-mode-hook-name mode)))
     (if (boundp hooks-name)
 	(run-hooks hooks-name))))
 
 ;; Functions to merge maps and tables.
 
 (defun derived-mode-merge-keymaps (old new)
-  "Merge an old keymap into a new one.
-The old keymap is set to be the cdr of the new one, so that there will
+  "Merge an OLD keymap into a NEW one.
+The old keymap is set to be the last cdr of the new one, so that there will
 be automatic inheritance."
+  ;; ?? Can this just use `set-keymap-parent'?
+  (let ((tail new))
+    ;; Scan the NEW map for prefix keys.
+    (while (consp tail)
+      (and (consp (car tail))
+	   (let* ((key (vector (car (car tail))))
+		  (subnew (lookup-key new key))
+		  (subold (lookup-key old key)))
+	     ;; If KEY is a prefix key in both OLD and NEW, merge them.
+	     (and (keymapp subnew) (keymapp subold)
+		  (derived-mode-merge-keymaps subold subnew))))
+      (and (vectorp (car tail))
+	   ;; Search a vector of ASCII char bindings for prefix keys.
+	   (let ((i (1- (length (car tail)))))
+	     (while (>= i 0)
+	       (let* ((key (vector i))
+		      (subnew (lookup-key new key))
+		      (subold (lookup-key old key)))
+		 ;; If KEY is a prefix key in both OLD and NEW, merge them.
+		 (and (keymapp subnew) (keymapp subold)
+		      (derived-mode-merge-keymaps subold subnew)))
+	       (setq i (1- i)))))
+      (setq tail (cdr tail))))
   (setcdr (nthcdr (1- (length new)) new) old))
 
 (defun derived-mode-merge-syntax-tables (old new)
-  "Merge an old syntax table into a new one.
+  "Merge an OLD syntax table into a NEW one.
 Where the new table already has an entry, nothing is copied from the old one."
-  (let ((idx 0)
-	(end (min (length new) (length old))))
-    (while (< idx end)
-      (if (not (aref new idx))
-	  (aset new idx (aref old idx)))
-      (setq idx (1+ idx)))))
+  (set-char-table-parent new old))
 
 ;; Merge an old abbrev table into a new one.
 ;; This function requires internal knowledge of how abbrev tables work,
@@ -317,14 +393,13 @@ Where the new table already has an entry, nothing is copied from the old one."
 ;; as the value of the symbol, and the hook as the function definition.
 (defun derived-mode-merge-abbrev-tables (old new)
   (if old
-      (mapatoms 
-       (function 
-	(lambda (symbol)
-	  (or (intern-soft (symbol-name symbol) new)
-	      (define-abbrev new (symbol-name symbol)
-		(symbol-value symbol) (symbol-function symbol)))))
+      (mapatoms
+       (lambda (symbol)
+	 (or (intern-soft (symbol-name symbol) new)
+	     (define-abbrev new (symbol-name symbol)
+	       (symbol-value symbol) (symbol-function symbol))))
        old)))
-    
+
 (provide 'derived)
 
 ;;; derived.el ends here