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Diffstat (limited to 'lisp/derived.el')
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diff --git a/lisp/derived.el b/lisp/derived.el deleted file mode 100644 index 48824a61ec2..00000000000 --- a/lisp/derived.el +++ /dev/null @@ -1,352 +0,0 @@ -;;; derived.el --- allow inheritance of major modes. -;;; (formerly mode-clone.el) - -;; Copyright (C) 1993, 1994 Free Software Foundation, Inc. - -;; Author: David Megginson (dmeggins@aix1.uottawa.ca) -;; Maintainer: FSF - -;; 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. -;; - **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,' -;; 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-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 - -;;; Code: - -;; 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 (ie. text-mode). -NAME: a string which will appear in the status line (ie. \"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. - -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." - - ; 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) - ; Run the parent. - ((, parent)) - ; Identify special modes. - (if (get (quote (, parent)) 'special) - (put (quote (, child)) 'special t)) - ; Identify the child mode. - (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))) - ; 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))))))) - - -;; 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." - (while (get mode 'derived-mode-parent) - (setq mode (get mode 'derived-mode-parent))) - mode) - - -;; 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"))) - -(defsubst derived-mode-hooks-name (mode) - "Construct a hooks name based on a mode name." - (intern (concat (symbol-name mode) "-hooks"))) - -(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. - -;;;###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))))))) - -(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." - (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 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 hooks if they exist." - - (let ((hooks-name (derived-mode-hooks-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." - (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 - (function - (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 |