[Emacs-diffs] Changes to emacs/lisp/emacs-lisp/derived.el [lexbind]

[Miles Bader]

Index: emacs/lisp/emacs-lisp/derived.el
diff -c /dev/null emacs/lisp/emacs-lisp/derived.el:1.3.2.1
*** /dev/null   Tue Oct 14 19:32:24 2003
--- emacs/lisp/emacs-lisp/derived.el    Tue Oct 14 19:32:21 2003
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*** 0 ****
--- 1,441 ----
+ ;;; derived.el --- allow inheritance of major modes
+ ;;; (formerly mode-clone.el)
+ 
+ ;; Copyright (C) 1993, 1994, 1999, 2003 Free Software Foundation, Inc.
+ 
+ ;; Author: David Megginson (address@hidden)
+ ;; Maintainer: FSF
+ ;; Keywords: extensions
+ 
+ ;; 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)
+ ;; any later version.
+ 
+ ;; 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.
+ 
+ ;;; Commentary:
+ 
+ ;; 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
+ ;; (commands) by means of a keymap.
+ ;;
+ ;; The only thing missing is a good scheme of inheritance.  It is
+ ;; possible to simulate a single level of inheritance with generous
+ ;; use of hooks and a bit of work -- sgml-mode, for example, also runs
+ ;; the hooks for text-mode, and keymaps can inherit from other keymaps
+ ;; -- but generally, each major mode ends up reinventing the wheel.
+ ;; Ideally, someone should redesign all of Emacs's major modes to
+ ;; follow a more conventional object-oriented system: when defining a
+ ;; new major mode, the user should need only to name the existing mode
+ ;; it is most similar to, then list the (few) differences.
+ ;;
+ ;; In the mean time, this package offers most of the advantages of
+ ;; full inheritance with the existing major modes.  The macro
+ ;; `define-derived-mode' allows the user to make a variant of an existing
+ ;; major mode, with its own keymap.  The new mode will inherit the key
+ ;; bindings of its parent, and will, in fact, run its parent first
+ ;; every time it is called.  For example, the commands
+ ;;
+ ;;  (define-derived-mode hypertext-mode text-mode "Hypertext"
+ ;;    "Major mode for hypertext.\n\n\\{hypertext-mode-map}"
+ ;;    (setq case-fold-search nil))
+ ;;
+ ;;  (define-key hypertext-mode-map [down-mouse-3] 'do-hyper-link)
+ ;;
+ ;; will create a function `hypertext-mode' with its own (sparse)
+ ;; keymap `hypertext-mode-map.'  The command M-x hypertext-mode will
+ ;; perform the following actions:
+ ;;
+ ;; - run the command (text-mode) to get its default setup
+ ;; - replace the current keymap with 'hypertext-mode-map,' which will
+ ;;   inherit from 'text-mode-map'.
+ ;; - replace the current syntax table with
+ ;;   'hypertext-mode-syntax-table', which will borrow its defaults
+ ;;   from the current text-mode-syntax-table.
+ ;; - replace the current abbrev table with
+ ;;   'hypertext-mode-abbrev-table', which will borrow its defaults
+ ;;   from the current text-mode-abbrev table
+ ;; - change the mode line to read "Hypertext"
+ ;; - 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.
+ ;;
+ ;; The advantages of this system are threefold.  First, text mode is
+ ;; untouched -- if you had added the new keystroke to `text-mode-map,'
+ ;; possibly using hooks, you would have added it to all text buffers
+ ;; -- here, it appears only in hypertext buffers, where it makes
+ ;; sense.  Second, it is possible to build even further, and make
+ ;; a derived mode from a derived mode.  The commands
+ ;;
+ ;;   (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-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:
+ 
+ (eval-when-compile (require 'cl))
+ 
+ ;;; 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
+ (defmacro define-derived-mode (child parent name &optional docstring &rest 
body)
+   "Create a new mode as a variant of an existing mode.
+ 
+ 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 (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.  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:
+ 
+   (define-derived-mode LaTeX-thesis-mode LaTeX-mode \"LaTeX-Thesis\")
+ 
+ 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
+ the parent, and then sets the variable `case-fold-search' to nil:
+ 
+   (define-derived-mode article-mode sgml-mode \"Article\"
+     \"Major mode for editing technical articles.\"
+     (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.
+ 
+ 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))
+ 
+     ;; 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
+        (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.
+        (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.
+         ,(when parent
+            `(progn
+               (if (get (quote ,parent) 'mode-class)
+                   (put (quote ,child) 'mode-class
+                        (get (quote ,parent) 'mode-class)))
+                                       ; Set up maps and tables.
+               (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 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.
+ 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.
+ 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 "21.4")
+ 
+ 
+ ;;; 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."
+   (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.
+ 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)
+              (make-sparse-keymap)
+              ,(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 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)))))
+ 
+ ;; 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."
+   (let* ((map-name (derived-mode-map-name mode))
+        (new-map (eval map-name))
+        (old-map (current-local-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."
+   (let* ((table-name (derived-mode-syntax-table-name mode))
+        (old-table (syntax-table))
+        (new-table (eval table-name)))
+     (if (get table-name 'derived-mode-unmerged)
+       (derived-mode-merge-syntax-tables old-table new-table))
+     (put table-name 'derived-mode-unmerged nil)
+     (set-syntax-table new-table)))
+ 
+ (defun derived-mode-set-abbrev-table (mode)
+   "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)
+        (new-table (eval table-name)))
+     (derived-mode-merge-abbrev-tables old-table new-table)
+     (setq local-abbrev-table new-table)))
+ 
+ ;;;(defun derived-mode-run-setup-function (mode)
+ ;;;  "Run the setup function if it exists."
+ 
+ ;;;  (let ((fname (derived-mode-setup-function-name mode)))
+ ;;;    (if (fboundp fname)
+ ;;;   (funcall fname))))
+ 
+ (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))))
+ 
+ ;; 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 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.
+ Where the new table already has an entry, nothing is copied from the old one."
+   (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,
+ ;; presuming that they are obarrays with the abbrev as the symbol, the 
expansion
+ ;; as the value of the symbol, and the hook as the function definition.
+ (defun derived-mode-merge-abbrev-tables (old new)
+   (if old
+       (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