--- a/lisp/derived.el	Wed Jun 16 21:50:51 2004 +0000
+++ b/lisp/derived.el	Thu Jun 17 03:01:17 2004 +0000
@@ -1,6 +1,7 @@
-;;; derived.el --- allow inheritance of major modes.
+;;; derived.el --- allow inheritance of major modes
+;;; (formerly mode-clone.el)
 
-;; Copyright (C) 1993, 1994, 1997 Free Software Foundation, Inc.
+;; Copyright (C) 1993, 1994, 1999, 2003 Free Software Foundation, Inc.
 
 ;; Author: David Megginson (dmeggins@aix1.uottawa.ca)
 ;; Maintainer: XEmacs Development Team
@@ -23,7 +24,7 @@
 ;; Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 ;; 02111-1307, USA.
 
-;;; Synched up with: FSF 19.34.
+;;; Synched up with: FSF 21.3.
 
 ;;; Commentary:
 
@@ -74,12 +75,6 @@
 ;; - 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,'
@@ -90,19 +85,34 @@
 ;;
 ;;   (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).
-;;
-;; (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.
 
 ;; XEmacs -- no autoload
@@ -112,12 +122,24 @@
 The arguments to this command are as follow:
 
 CHILD:     the name of the command for the derived mode.
-PARENT:    the name of the command for the parent mode (ie. text-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.
+
+BODY can start with a bunch of keyword arguments.  The following keyword
+  arguments are currently understood:
+:group GROUP
+	Declare the customization group that corresponds to this mode.
+:syntax-table TABLE
+	Use TABLE instead of the default.
+	A nil value means to simply use the same syntax-table as the parent.
+:abbrev-table TABLE
+	Use TABLE instead of the default.
+	A nil value means to simply use the same abbrev-table as the parent.
 
 Here is how you could define LaTeX-Thesis mode as a variant of LaTeX mode:
 
@@ -127,7 +149,7 @@
 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\"
@@ -135,58 +157,101 @@
     (setq case-fold-search nil))
 
 Note that if the documentation string had been left out, it would have
-been generated automatically, with a reference to the keymap."
+been generated automatically, with a reference to the keymap.
+
+The new mode runs the hook constructed by the function
+`derived-mode-hook-name'."
+  (declare (debug (&define name symbolp sexp [&optional stringp]
+			   [&rest keywordp sexp] def-body)))
+
+  (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))
+	(declare-abbrev t)
+	(declare-syntax t)
+	(hook (derived-mode-hook-name child))
+	(group nil))
 
-					; 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)))
+    ;; Process the keyword args.
+    (while (keywordp (car body))
+      (case (pop body)
+	(:group (setq group (pop body)))
+	(:abbrev-table (setq abbrev (pop body)) (setq declare-abbrev nil))
+	(:syntax-table (setq syntax (pop body)) (setq declare-syntax nil))
+	(t (pop body))))
+
+    (setq docstring (derived-mode-make-docstring
+		     parent child docstring syntax abbrev))
 
-  `(progn 
-       (derived-mode-init-mode-variables (quote ,child))
-       (put (quote ,child) 'derived-mode-parent (quote ,parent))
+    `(progn
+       (defvar ,hook nil ,(format "Hook run when entering %s mode." name))
+       (defvar ,map (make-sparse-keymap))
+       ,(if declare-syntax
+	    `(defvar ,syntax (make-syntax-table)))
+       ,(if declare-abbrev
+	    `(defvar ,abbrev
+	       (progn (define-abbrev-table ',abbrev nil) ,abbrev)))
+       (put ',child 'derived-mode-parent ',parent)
+       ,(if group `(put ',child 'custom-mode-group ,group))
+
        (defun ,child ()
 	 ,docstring
 	 (interactive)
 					; Run the parent.
-	 (,parent)
+	 (delay-mode-hooks
+
+	  (,(or parent 'kill-all-local-variables))
+					; Identify the child mode.
+	  (setq major-mode (quote ,child))
+	  (setq mode-name ,name)
 					; Identify special modes.
-	 (if (get (quote ,parent) 'special)
-	     (put (quote ,child) 'special t))
-	 ;; XEmacs addition
-	 (let ((mode-class (get (quote ,parent) 'mode-class)))
-	   (if mode-class
-	       (put (quote ,child) 'mode-class mode-class)))
-					; Identify the child mode.
-	 (setq major-mode (quote ,child))
-	 (setq mode-name ,name)
+	  ,(when parent
+	     `(progn
+		(if (get (quote ,parent) 'mode-class)
+		    (put (quote ,child) 'mode-class
+			 (get (quote ,parent) 'mode-class)))
 					; 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)))
+		,(when declare-syntax
+		   `(let ((parent (char-table-parent ,syntax)))
+		      (unless (and parent
+				   (not (eq parent (standard-syntax-table))))
+			(set-char-table-parent ,syntax (syntax-table)))))))
+
+	  (use-local-map ,map)
+	  ,(when syntax `(set-syntax-table ,syntax))
+	  ,(when abbrev `(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))
-					; Run the hooks, if any.
-	 (derived-mode-run-hooks (quote ,child)))))
-
+	  ,@body
+	  )
+	 ;; Run the hooks, if any.
+	 ;; Make the generated code work in older Emacs versions
+	 ;; that do not yet have run-mode-hooks.
+	 (if (fboundp 'run-mode-hooks)
+	     (run-mode-hooks ',hook)
+	   (run-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 all derive from `fundamental-mode', this function
+is not very useful."
   (while (get mode 'derived-mode-parent)
     (setq mode (get mode 'derived-mode-parent)))
   mode)
+(make-obsolete 'derived-mode-class 'derived-mode-p)
 
 ;; PUBLIC: find if the current mode derives from another.
 ;; from GNU Emacs 21 subr.el
@@ -200,35 +265,66 @@
     parent))
 
 
-;; Inline functions to construct various names from a mode name.
+;;; PRIVATE
+
+(defun derived-mode-make-docstring (parent child &optional
+					   docstring syntax abbrev)
+  "Construct a docstring for a new mode if none is provided."
+
+  (let ((map (derived-mode-map-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:
+
+  `%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 (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."
+  "Construct a setup-function name based on a MODE name."
   (intern (concat (symbol-name mode) "-setup")))
 
-(defsubst derived-mode-hooks-name (mode)
-  "Construct a hooks name based on a mode name."
-  ;; XEmacs change from -hooks
-  (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")))
-
 
 ;; Utility functions for defining a derived mode.
 
 ;; XEmacs -- don't autoload
 (defun derived-mode-init-mode-variables (mode)
-  "Initialize 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."
@@ -256,30 +352,15 @@
   (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))
+	     (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))
-
 
 ;; 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)))
@@ -289,8 +370,8 @@
     (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)))
@@ -300,7 +381,7 @@
     (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)
@@ -316,53 +397,45 @@
 ;;;	(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 parent 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."
-  ;; XEmacs change.  FSF 19.30 & 19.34 has a whole bunch of weird crap here
+  ;; XEmacs change.  FSF 19.30 to 21.3 has a whole bunch of weird crap here
   ;; for merging prefix keys and such.  Hopefully none of this is
   ;; necessary in XEmacs.
   (set-keymap-parents new (list 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."
-  ;; 20.x
-  (if (fboundp 'map-char-table)
-      ;; we use map-char-table not map-syntax-table so we can explicitly
-      ;; check for inheritance.
-      (map-char-table
-       #'(lambda (key value)
-	   (let ((newval (get-range-char-table key new 'multi)))
-	     (cond ((eq newval 'multi)	; OK, dive into the class hierarchy
-		    (map-char-table
-		     #'(lambda (key1 value1)
-			 (when (eq ?@ (char-syntax-from-code
-				       (get-range-char-table key new ?@)))
-			   (put-char-table key1 value new))
-			 nil)
-		     new
-		     key))
-		   ((eq ?@ (char-syntax-from-code newval)) ;; class at once
-		    (put-char-table key value new))))
-	   nil)
-       old)
-    ;; pre-20.0
-    (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))))))
+  ;; XEmacs change: on the other hand, Emacs 21.3 just has
+  ;; (set-char-table-parent new old) here.
+  ;; We use map-char-table, not map-syntax-table, so we can explicitly
+  ;; check for inheritance.
+  (map-char-table
+   #'(lambda (key value)
+       (let ((newval (get-range-char-table key new 'multi)))
+	 (cond ((eq newval 'multi)	; OK, dive into the class hierarchy
+		(map-char-table
+		 #'(lambda (key1 value1)
+		     (when (eq ?@ (char-syntax-from-code
+				   (get-range-char-table key new ?@)))
+		       (put-char-table key1 value new))
+		     nil)
+		 new
+		 key))
+	       ((eq ?@ (char-syntax-from-code newval)) ;; class at once
+		(put-char-table key value new))))
+       nil)
+   old))
 
 ;; Merge an old abbrev table into a new one.
 ;; This function requires internal knowledge of how abbrev tables work,
@@ -370,14 +443,14 @@
 ;; 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)
 
+;;; arch-tag: 630be248-47d1-4f02-afa0-8207de0ebea0
 ;;; derived.el ends here