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+ − 1 ;;; derived.el --- allow inheritance of major modes
+ − 2 ;;; (formerly mode-clone.el)
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+ − 3
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+ − 4 ;; Copyright (C) 1993, 1994, 1999, 2003 Free Software Foundation, Inc.
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+ − 5
+ − 6 ;; Author: David Megginson (dmeggins@aix1.uottawa.ca)
+ − 7 ;; Maintainer: XEmacs Development Team
+ − 8 ;; Keywords: extensions, dumped
+ − 9
+ − 10 ;; This file is part of XEmacs.
+ − 11
+ − 12 ;; XEmacs is free software; you can redistribute it and/or modify it
+ − 13 ;; under the terms of the GNU General Public License as published by
+ − 14 ;; the Free Software Foundation; either version 2, or (at your option)
+ − 15 ;; any later version.
+ − 16
+ − 17 ;; XEmacs is distributed in the hope that it will be useful, but
+ − 18 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
+ − 19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ − 20 ;; General Public License for more details.
+ − 21
+ − 22 ;; You should have received a copy of the GNU General Public License
+ − 23 ;; along with XEmacs; see the file COPYING. If not, write to the Free
+ − 24 ;; Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ − 25 ;; 02111-1307, USA.
+ − 26
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+ − 27 ;;; Synched up with: FSF 21.3.
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+ − 28
+ − 29 ;;; Commentary:
+ − 30
+ − 31 ;; This file is dumped with XEmacs.
+ − 32
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+ − 33 ;; XEmacs is already, in a sense, object oriented -- each object
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+ − 34 ;; (buffer) belongs to a class (major mode), and that class defines
+ − 35 ;; the relationship between messages (input events) and methods
+ − 36 ;; (commands) by means of a keymap.
+ − 37 ;;
+ − 38 ;; The only thing missing is a good scheme of inheritance. It is
+ − 39 ;; possible to simulate a single level of inheritance with generous
+ − 40 ;; use of hooks and a bit of work -- sgml-mode, for example, also runs
+ − 41 ;; the hooks for text-mode, and keymaps can inherit from other keymaps
+ − 42 ;; -- but generally, each major mode ends up reinventing the wheel.
+ − 43 ;; Ideally, someone should redesign all of Emacs's major modes to
+ − 44 ;; follow a more conventional object-oriented system: when defining a
+ − 45 ;; new major mode, the user should need only to name the existing mode
+ − 46 ;; it is most similar to, then list the (few) differences.
+ − 47 ;;
+ − 48 ;; In the mean time, this package offers most of the advantages of
+ − 49 ;; full inheritance with the existing major modes. The macro
+ − 50 ;; `define-derived-mode' allows the user to make a variant of an existing
+ − 51 ;; major mode, with its own keymap. The new mode will inherit the key
+ − 52 ;; bindings of its parent, and will, in fact, run its parent first
+ − 53 ;; every time it is called. For example, the commands
+ − 54 ;;
+ − 55 ;; (define-derived-mode hypertext-mode text-mode "Hypertext"
+ − 56 ;; "Major mode for hypertext.\n\n\\{hypertext-mode-map}"
+ − 57 ;; (setq case-fold-search nil))
+ − 58 ;;
+ − 59 ;; (define-key hypertext-mode-map [down-mouse-3] 'do-hyper-link)
+ − 60 ;;
+ − 61 ;; will create a function `hypertext-mode' with its own (sparse)
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+ − 62 ;; keymap `hypertext-mode-map'. The command M-x hypertext-mode will
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+ − 63 ;; perform the following actions:
+ − 64 ;;
+ − 65 ;; - run the command (text-mode) to get its default setup
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+ − 66 ;; - replace the current keymap with 'hypertext-mode-map', which will
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+ − 67 ;; inherit from 'text-mode-map'.
+ − 68 ;; - replace the current syntax table with
+ − 69 ;; 'hypertext-mode-syntax-table', which will borrow its defaults
+ − 70 ;; from the current text-mode-syntax-table.
+ − 71 ;; - replace the current abbrev table with
+ − 72 ;; 'hypertext-mode-abbrev-table', which will borrow its defaults
+ − 73 ;; from the current text-mode-abbrev table
+ − 74 ;; - change the mode line to read "Hypertext"
+ − 75 ;; - assign the value 'hypertext-mode' to the 'major-mode' variable
+ − 76 ;; - run the body of commands provided in the macro -- in this case,
+ − 77 ;; set the local variable `case-fold-search' to nil.
+ − 78 ;;
+ − 79 ;; The advantages of this system are threefold. First, text mode is
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+ − 80 ;; untouched -- if you had added the new keystroke to `text-mode-map',
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+ − 81 ;; possibly using hooks, you would have added it to all text buffers
+ − 82 ;; -- here, it appears only in hypertext buffers, where it makes
+ − 83 ;; sense. Second, it is possible to build even further, and make
+ − 84 ;; a derived mode from a derived mode. The commands
+ − 85 ;;
+ − 86 ;; (define-derived-mode html-mode hypertext-mode "HTML")
+ − 87 ;; [various key definitions]
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+ − 88 ;;
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+ − 89 ;; will add a new major mode for HTML with very little fuss.
+ − 90 ;;
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+ − 91 ;; Note also the function `derived-mode-p' which can tell if the current
+ − 92 ;; mode derives from another. In a hypertext-mode, buffer, for example,
+ − 93 ;; (derived-mode-p 'text-mode) would return non-nil. This should always
+ − 94 ;; be used in place of (eq major-mode 'text-mode).
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+ − 95
+ − 96 ;;; Code:
+ − 97
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+ − 98 ;;; PRIVATE: defsubst must be defined before they are first used
+ − 99
+ − 100 (defsubst derived-mode-hook-name (mode)
+ − 101 "Construct the mode hook name based on mode name MODE."
+ − 102 (intern (concat (symbol-name mode) "-hook")))
+ − 103
+ − 104 (defsubst derived-mode-map-name (mode)
+ − 105 "Construct a map name based on a MODE name."
+ − 106 (intern (concat (symbol-name mode) "-map")))
+ − 107
+ − 108 (defsubst derived-mode-syntax-table-name (mode)
+ − 109 "Construct a syntax-table name based on a MODE name."
+ − 110 (intern (concat (symbol-name mode) "-syntax-table")))
+ − 111
+ − 112 (defsubst derived-mode-abbrev-table-name (mode)
+ − 113 "Construct an abbrev-table name based on a MODE name."
+ − 114 (intern (concat (symbol-name mode) "-abbrev-table")))
+ − 115
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+ − 116 ;; PUBLIC: define a new major mode which inherits from an existing one.
+ − 117
+ − 118 ;; XEmacs -- no autoload
+ − 119 (defmacro define-derived-mode (child parent name &optional docstring &rest body)
+ − 120 "Create a new mode as a variant of an existing mode.
+ − 121
+ − 122 The arguments to this command are as follow:
+ − 123
+ − 124 CHILD: the name of the command for the derived mode.
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+ − 125 PARENT: the name of the command for the parent mode (e.g. `text-mode')
+ − 126 or nil if there is no parent.
+ − 127 NAME: a string which will appear in the status line (e.g. \"Hypertext\")
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+ − 128 DOCSTRING: an optional documentation string--if you do not supply one,
+ − 129 the function will attempt to invent something useful.
+ − 130 BODY: forms to execute just before running the
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+ − 131 hooks for the new mode. Do not use `interactive' here.
+ − 132
+ − 133 BODY can start with a bunch of keyword arguments. The following keyword
+ − 134 arguments are currently understood:
+ − 135 :group GROUP
+ − 136 Declare the customization group that corresponds to this mode.
+ − 137 :syntax-table TABLE
+ − 138 Use TABLE instead of the default.
+ − 139 A nil value means to simply use the same syntax-table as the parent.
+ − 140 :abbrev-table TABLE
+ − 141 Use TABLE instead of the default.
+ − 142 A nil value means to simply use the same abbrev-table as the parent.
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+ − 143
+ − 144 Here is how you could define LaTeX-Thesis mode as a variant of LaTeX mode:
+ − 145
+ − 146 (define-derived-mode LaTeX-thesis-mode LaTeX-mode \"LaTeX-Thesis\")
+ − 147
+ − 148 You could then make new key bindings for `LaTeX-thesis-mode-map'
+ − 149 without changing regular LaTeX mode. In this example, BODY is empty,
+ − 150 and DOCSTRING is generated by default.
+ − 151
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+ − 152 On a more complicated level, the following command uses `sgml-mode' as
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+ − 153 the parent, and then sets the variable `case-fold-search' to nil:
+ − 154
+ − 155 (define-derived-mode article-mode sgml-mode \"Article\"
+ − 156 \"Major mode for editing technical articles.\"
+ − 157 (setq case-fold-search nil))
+ − 158
+ − 159 Note that if the documentation string had been left out, it would have
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+ − 160 been generated automatically, with a reference to the keymap.
+ − 161
+ − 162 The new mode runs the hook constructed by the function
+ − 163 `derived-mode-hook-name'."
+ − 164 (declare (debug (&define name symbolp sexp [&optional stringp]
+ − 165 [&rest keywordp sexp] def-body)))
+ − 166
+ − 167 (when (and docstring (not (stringp docstring)))
+ − 168 ;; Some trickiness, since what appears to be the docstring may really be
+ − 169 ;; the first element of the body.
+ − 170 (push docstring body)
+ − 171 (setq docstring nil))
+ − 172
+ − 173 (when (eq parent 'fundamental-mode) (setq parent nil))
+ − 174
+ − 175 (let ((map (derived-mode-map-name child))
+ − 176 (syntax (derived-mode-syntax-table-name child))
+ − 177 (abbrev (derived-mode-abbrev-table-name child))
+ − 178 (declare-abbrev t)
+ − 179 (declare-syntax t)
+ − 180 (hook (derived-mode-hook-name child))
+ − 181 (group nil))
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+ − 182
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+ − 183 ;; Process the keyword args.
+ − 184 (while (keywordp (car body))
+ − 185 (case (pop body)
+ − 186 (:group (setq group (pop body)))
+ − 187 (:abbrev-table (setq abbrev (pop body)) (setq declare-abbrev nil))
+ − 188 (:syntax-table (setq syntax (pop body)) (setq declare-syntax nil))
+ − 189 (t (pop body))))
+ − 190
+ − 191 (setq docstring (derived-mode-make-docstring
+ − 192 parent child docstring syntax abbrev))
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+ − 193
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+ − 194 `(progn
+ − 195 (defvar ,hook nil ,(format "Hook run when entering %s mode." name))
+ − 196 (defvar ,map (make-sparse-keymap))
+ − 197 ,(if declare-syntax
+ − 198 `(defvar ,syntax (make-syntax-table)))
+ − 199 ,(if declare-abbrev
+ − 200 `(defvar ,abbrev
+ − 201 (progn (define-abbrev-table ',abbrev nil) ,abbrev)))
+ − 202 (put ',child 'derived-mode-parent ',parent)
+ − 203 ,(if group `(put ',child 'custom-mode-group ,group))
+ − 204
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+ − 205 (defun ,child ()
+ − 206 ,docstring
+ − 207 (interactive)
+ − 208 ; Run the parent.
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+ − 209 (delay-mode-hooks
+ − 210
+ − 211 (,(or parent 'kill-all-local-variables))
+ − 212 ; Identify the child mode.
+ − 213 (setq major-mode (quote ,child))
+ − 214 (setq mode-name ,name)
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+ − 215 ; Identify special modes.
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+ − 216 ,(when parent
+ − 217 `(progn
+ − 218 (if (get (quote ,parent) 'mode-class)
+ − 219 (put (quote ,child) 'mode-class
+ − 220 (get (quote ,parent) 'mode-class)))
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+ − 221 ; Set up maps and tables.
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+ − 222 (unless (keymap-parent ,map)
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+ − 223 (set-keymap-parents ,map (list (current-local-map))))
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+ − 224 ,(when declare-syntax
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+ − 225 ;; XEmacs change: we do not have char-table-parent
+ − 226 `(derived-mode-merge-syntax-tables
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+ − 227 (syntax-table) ,syntax))))
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+ − 228
+ − 229 (use-local-map ,map)
+ − 230 ,(when syntax `(set-syntax-table ,syntax))
+ − 231 ,(when abbrev `(setq local-abbrev-table ,abbrev))
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+ − 232 ; Splice in the body (if any).
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+ − 233 ,@body
+ − 234 )
+ − 235 ;; Run the hooks, if any.
+ − 236 ;; Make the generated code work in older Emacs versions
+ − 237 ;; that do not yet have run-mode-hooks.
+ − 238 (if (fboundp 'run-mode-hooks)
+ − 239 (run-mode-hooks ',hook)
+ − 240 (run-hooks ',hook))))))
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+ − 241
+ − 242 ;; PUBLIC: find the ultimate class of a derived mode.
+ − 243
+ − 244 (defun derived-mode-class (mode)
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+ − 245 "Find the class of a major MODE.
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+ − 246 A mode's class is the first ancestor which is NOT a derived mode.
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+ − 247 Use the `derived-mode-parent' property of the symbol to trace backwards.
+ − 248 Since major-modes might all derive from `fundamental-mode', this function
+ − 249 is not very useful."
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+ − 250 (while (get mode 'derived-mode-parent)
+ − 251 (setq mode (get mode 'derived-mode-parent)))
+ − 252 mode)
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+ − 253 (make-obsolete 'derived-mode-class 'derived-mode-p)
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+ − 254
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+ − 255 ;; PUBLIC: find if the current mode derives from another.
+ − 256 ;; from GNU Emacs 21 subr.el
+ − 257
+ − 258 (defun derived-mode-p (&rest modes)
+ − 259 "Non-nil if the current major mode is derived from one of MODES.
+ − 260 Uses the `derived-mode-parent' property of the symbol to trace backwards."
+ − 261 (let ((parent major-mode))
+ − 262 (while (and (not (memq parent modes))
+ − 263 (setq parent (get parent 'derived-mode-parent))))
+ − 264 parent))
+ − 265
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+ − 266
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+ − 267 ;;; PRIVATE
+ − 268
+ − 269 (defun derived-mode-make-docstring (parent child &optional
+ − 270 docstring syntax abbrev)
+ − 271 "Construct a docstring for a new mode if none is provided."
+ − 272
+ − 273 (let ((map (derived-mode-map-name child))
+ − 274 (hook (derived-mode-hook-name child)))
+ − 275
+ − 276 (unless (stringp docstring)
+ − 277 ;; Use a default docstring.
+ − 278 (setq docstring
+ − 279 (if (null parent)
+ − 280 (format "Major-mode.
+ − 281 Uses keymap `%s', abbrev table `%s' and syntax-table `%s'." map abbrev syntax)
+ − 282 (format "Major mode derived from `%s' by `define-derived-mode'.
+ − 283 It inherits all of the parent's attributes, but has its own keymap,
+ − 284 abbrev table and syntax table:
+ − 285
+ − 286 `%s', `%s' and `%s'
+ − 287
+ − 288 which more-or-less shadow %s's corresponding tables."
+ − 289 parent map abbrev syntax parent))))
+ − 290
+ − 291 (unless (string-match (regexp-quote (symbol-name hook)) docstring)
+ − 292 ;; Make sure the docstring mentions the mode's hook.
+ − 293 (setq docstring
+ − 294 (concat docstring
+ − 295 (if (null parent)
+ − 296 "\n\nThis mode "
+ − 297 (concat
+ − 298 "\n\nIn addition to any hooks its parent mode "
+ − 299 (if (string-match (regexp-quote (format "`%s'" parent))
+ − 300 docstring) nil
+ − 301 (format "`%s' " parent))
+ − 302 "might have run,\nthis mode "))
+ − 303 (format "runs the hook `%s'" hook)
+ − 304 ", as the final step\nduring initialization.")))
+ − 305
+ − 306 (unless (string-match "\\\\[{[]" docstring)
+ − 307 ;; And don't forget to put the mode's keymap.
+ − 308 (setq docstring (concat docstring "\n\n\\{" (symbol-name map) "}")))
+ − 309
+ − 310 docstring))
+ − 311
+ − 312
+ − 313 ;;; OBSOLETE
+ − 314 ;; The functions below are only provided for backward compatibility with
+ − 315 ;; code byte-compiled with versions of derived.el prior to Emacs-21.
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+ − 316
+ − 317 (defsubst derived-mode-setup-function-name (mode)
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+ − 318 "Construct a setup-function name based on a MODE name."
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+ − 319 (intern (concat (symbol-name mode) "-setup")))
+ − 320
+ − 321
+ − 322 ;; Utility functions for defining a derived mode.
+ − 323
+ − 324 ;; XEmacs -- don't autoload
+ − 325 (defun derived-mode-init-mode-variables (mode)
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+ − 326 "Initialise variables for a new MODE.
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+ − 327 Right now, if they don't already exist, set up a blank keymap, an
+ − 328 empty syntax table, and an empty abbrev table -- these will be merged
+ − 329 the first time the mode is used."
+ − 330
+ − 331 (if (boundp (derived-mode-map-name mode))
+ − 332 t
+ − 333 (eval `(defvar ,(derived-mode-map-name mode)
+ − 334 ;; XEmacs change
+ − 335 (make-sparse-keymap (derived-mode-map-name mode))
+ − 336 ,(format "Keymap for %s." mode)))
+ − 337 (put (derived-mode-map-name mode) 'derived-mode-unmerged t))
+ − 338
+ − 339 (if (boundp (derived-mode-syntax-table-name mode))
+ − 340 t
+ − 341 (eval `(defvar ,(derived-mode-syntax-table-name mode)
+ − 342 ;; XEmacs change
+ − 343 ;; Make a syntax table which doesn't specify anything
+ − 344 ;; for any char. Valid data will be merged in by
+ − 345 ;; derived-mode-merge-syntax-tables.
+ − 346 ;; (make-char-table 'syntax-table nil)
+ − 347 (make-syntax-table)
+ − 348 ,(format "Syntax table for %s." mode)))
+ − 349 (put (derived-mode-syntax-table-name mode) 'derived-mode-unmerged t))
+ − 350
+ − 351 (if (boundp (derived-mode-abbrev-table-name mode))
+ − 352 t
+ − 353 (eval `(defvar ,(derived-mode-abbrev-table-name mode)
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+ − 354 (progn
+ − 355 (define-abbrev-table (derived-mode-abbrev-table-name mode) nil)
+ − 356 (make-abbrev-table))
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+ − 357 ,(format "Abbrev table for %s." mode)))))
+ − 358
+ − 359 ;; Utility functions for running a derived mode.
+ − 360
+ − 361 (defun derived-mode-set-keymap (mode)
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+ − 362 "Set the keymap of the new MODE, maybe merging with the parent."
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+ − 363 (let* ((map-name (derived-mode-map-name mode))
+ − 364 (new-map (eval map-name))
+ − 365 (old-map (current-local-map)))
+ − 366 (and old-map
+ − 367 (get map-name 'derived-mode-unmerged)
+ − 368 (derived-mode-merge-keymaps old-map new-map))
+ − 369 (put map-name 'derived-mode-unmerged nil)
+ − 370 (use-local-map new-map)))
+ − 371
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+ − 372 (defun derived-mode-set-syntax-table (mode)
+ − 373 "Set the syntax table of the new MODE, maybe merging with the parent."
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+ − 374 (let* ((table-name (derived-mode-syntax-table-name mode))
+ − 375 (old-table (syntax-table))
+ − 376 (new-table (eval table-name)))
+ − 377 (if (get table-name 'derived-mode-unmerged)
+ − 378 (derived-mode-merge-syntax-tables old-table new-table))
+ − 379 (put table-name 'derived-mode-unmerged nil)
+ − 380 (set-syntax-table new-table)))
+ − 381
+ − 382 (defun derived-mode-set-abbrev-table (mode)
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+ − 383 "Set the abbrev table for MODE if it exists.
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+ − 384 Always merge its parent into it, since the merge is non-destructive."
+ − 385 (let* ((table-name (derived-mode-abbrev-table-name mode))
+ − 386 (old-table local-abbrev-table)
+ − 387 (new-table (eval table-name)))
+ − 388 (derived-mode-merge-abbrev-tables old-table new-table)
+ − 389 (setq local-abbrev-table new-table)))
+ − 390
+ − 391 ;;;(defun derived-mode-run-setup-function (mode)
+ − 392 ;;; "Run the setup function if it exists."
+ − 393
+ − 394 ;;; (let ((fname (derived-mode-setup-function-name mode)))
+ − 395 ;;; (if (fboundp fname)
+ − 396 ;;; (funcall fname))))
+ − 397
+ − 398 (defun derived-mode-run-hooks (mode)
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+ − 399 "Run the mode hook for MODE."
+ − 400 (let ((hooks-name (derived-mode-hook-name mode)))
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+ − 401 (if (boundp hooks-name)
+ − 402 (run-hooks hooks-name))))
+ − 403
+ − 404 ;; Functions to merge maps and tables.
+ − 405
+ − 406 (defun derived-mode-merge-keymaps (old new)
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+ − 407 "Merge an OLD keymap into a NEW one.
+ − 408 The old keymap is set to be the last cdr of the new one, so that there will
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+ − 409 be automatic inheritance."
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+ − 410 ;; XEmacs change. FSF 19.30 to 21.3 has a whole bunch of weird crap here
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+ − 411 ;; for merging prefix keys and such. Hopefully none of this is
+ − 412 ;; necessary in XEmacs.
+ − 413 (set-keymap-parents new (list old)))
+ − 414
+ − 415 (defun derived-mode-merge-syntax-tables (old new)
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+ − 416 "Merge an OLD syntax table into a NEW one.
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+ − 417 Where the new table already has an entry, nothing is copied from the old one."
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+ − 418 ;; XEmacs change: on the other hand, Emacs 21.3 just has
+ − 419 ;; (set-char-table-parent new old) here.
+ − 420 ;; We use map-char-table, not map-syntax-table, so we can explicitly
+ − 421 ;; check for inheritance.
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+ − 422 (map-char-table
+ − 423 #'(lambda (key value)
+ − 424 (let ((newval (get-range-char-table key new 'multi)))
+ − 425 (cond ((eq newval 'multi) ; OK, dive into the class hierarchy
+ − 426 (map-char-table
+ − 427 #'(lambda (key1 value1)
+ − 428 (when (eq ?@ (char-syntax-from-code
+ − 429 (get-range-char-table key new ?@)))
+ − 430 (put-char-table key1 value new))
+ − 431 nil)
+ − 432 new
+ − 433 key))
+ − 434 ((eq ?@ (char-syntax-from-code newval)) ;; class at once
+ − 435 (put-char-table key value new))))
+ − 436 nil)
+ − 437 old))
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+ − 438
+ − 439 ;; Merge an old abbrev table into a new one.
+ − 440 ;; This function requires internal knowledge of how abbrev tables work,
+ − 441 ;; presuming that they are obarrays with the abbrev as the symbol, the expansion
+ − 442 ;; as the value of the symbol, and the hook as the function definition.
+ − 443 (defun derived-mode-merge-abbrev-tables (old new)
+ − 444 (if old
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+ − 445 (mapatoms
+ − 446 #'(lambda (symbol)
+ − 447 (or (intern-soft (symbol-name symbol) new)
+ − 448 (define-abbrev new (symbol-name symbol)
+ − 449 (symbol-value symbol) (symbol-function symbol))))
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+ − 450 old)))
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+ − 451
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+ − 452 (provide 'derived)
+ − 453
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+ − 454 ;;; arch-tag: 630be248-47d1-4f02-afa0-8207de0ebea0
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+ − 455 ;;; derived.el ends here