code.delx.au - gnu-emacs/blob - lisp/mh-e/mh-compat.el

   1 ;;; mh-compat.el --- make MH-E compatible with various versions of Emacs
   2
   3 ;; Copyright (C) 2006-2015 Free Software Foundation, Inc.
   4
   5 ;; Author: Bill Wohler <wohler@newt.com>
   6 ;; Maintainer: Bill Wohler <wohler@newt.com>
   7 ;; Keywords: mail
   8 ;; See: mh-e.el
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;;; Change Log:
  28
  29 ;;; Code:
  30
  31 ;; This is a good place to gather code that is used for compatibility
  32 ;; between different versions of Emacs. Please document which versions
  33 ;; of Emacs that the defsubst, defalias, or defmacro applies. That
  34 ;; way, it's easy to occasionally go through this file and see which
  35 ;; macros we can retire.
  36
  37 ;; Please use mh-gnus.el when providing compatibility with different
  38 ;; versions of Gnus.
  39
  40 ;; Items are listed alphabetically (except for mh-require which is
  41 ;; needed sooner it would normally appear).
  42
  43 (require 'mh-acros)
  44
  45 (mh-do-in-gnu-emacs
  46   (defalias 'mh-require 'require))
  47
  48 (mh-do-in-xemacs
  49   (defun mh-require (feature &optional filename noerror)
  50     "If feature FEATURE is not loaded, load it from FILENAME.
  51 If FEATURE is not a member of the list `features', then the feature
  52 is not loaded; so load the file FILENAME.
  53 If FILENAME is omitted, the printname of FEATURE is used as the file name.
  54 If the optional third argument NOERROR is non-nil,
  55 then return nil if the file is not found instead of signaling an error.
  56
  57 Simulate NOERROR argument in XEmacs which lacks it."
  58     (if (not (featurep feature))
  59         (if filename
  60             (load filename noerror t)
  61           (load (format "%s" feature) noerror t)))))
  62
  63 (defun-mh mh-assoc-string assoc-string (key list case-fold)
  64   "Like `assoc' but specifically for strings.
  65 Case is ignored if CASE-FOLD is non-nil.
  66 This function is used by Emacs versions that lack `assoc-string',
  67 introduced in Emacs 22."
  68   (if case-fold
  69       (assoc-ignore-case key list)
  70     (assoc key list)))
  71
  72 ;; For XEmacs.
  73 (defalias 'mh-cancel-timer
  74   (if (fboundp 'cancel-timer)
  75       'cancel-timer
  76     'delete-itimer))
  77
  78 ;; Emacs 24 renamed flet to cl-flet.
  79 (defalias 'mh-cl-flet
  80   (if (fboundp 'cl-flet)
  81       'cl-flet
  82     'flet))
  83
  84 (defun mh-display-color-cells (&optional display)
  85   "Return the number of color cells supported by DISPLAY.
  86 This function is used by XEmacs to return 2 when `device-color-cells'
  87 or `display-color-cells' returns nil. This happens when compiling or
  88 running on a tty and causes errors since `display-color-cells' is
  89 expected to return an integer."
  90   (cond ((fboundp 'display-color-cells) ; GNU Emacs, XEmacs 21.5b28
  91          (or (display-color-cells display) 2))
  92         ((fboundp 'device-color-cells)  ; XEmacs 21.4
  93          (or (device-color-cells display) 2))
  94         (t 2)))
  95
  96 (defmacro mh-display-completion-list (completions &optional common-substring)
  97   "Display the list of COMPLETIONS.
  98 See documentation for `display-completion-list' for a description of the
  99 arguments COMPLETIONS.
 100 The optional argument COMMON-SUBSTRING, if non-nil, should be a string
 101 specifying a common substring for adding the faces
 102 `completions-first-difference' and `completions-common-part' to
 103 the completions."
 104   (cond ((< emacs-major-version 22) `(display-completion-list ,completions))
 105         ((fboundp 'completion-hilit-commonality) ; Emacs 23.1 and later
 106          `(display-completion-list
 107            (completion-hilit-commonality ,completions
 108                                          ,(length common-substring) nil)))
 109         (t                              ; Emacs 22
 110          `(display-completion-list ,completions ,common-substring))))
 111
 112 (defmacro mh-face-foreground (face &optional frame inherit)
 113   "Return the foreground color name of FACE, or nil if unspecified.
 114 See documentation for `face-foreground' for a description of the
 115 arguments FACE, FRAME, and perhaps INHERIT.
 116 This macro is used by Emacs versions that lack an INHERIT argument,
 117 introduced in Emacs 22."
 118   (if (< emacs-major-version 22)
 119       `(face-foreground ,face ,frame)
 120     `(face-foreground ,face ,frame ,inherit)))
 121
 122 (defmacro mh-face-background (face &optional frame inherit)
 123   "Return the background color name of face, or nil if unspecified.
 124 See documentation for `back-foreground' for a description of the
 125 arguments FACE, FRAME, and INHERIT.
 126 This macro is used by Emacs versions that lack an INHERIT argument,
 127 introduced in Emacs 22."
 128   (if (< emacs-major-version 22)
 129       `(face-background ,face ,frame)
 130     `(face-background ,face ,frame ,inherit)))
 131
 132 (defun-mh mh-font-lock-add-keywords font-lock-add-keywords
 133   (mode keywords &optional how)
 134   "XEmacs does not have `font-lock-add-keywords'.
 135 This function returns nil on that system.")
 136
 137 (defun-mh mh-image-load-path-for-library
 138   image-load-path-for-library (library image &optional path no-error)
 139   "Return a suitable search path for images used by LIBRARY.
 140
 141 It searches for IMAGE in `image-load-path' (excluding
 142 \"`data-directory'/images\") and `load-path', followed by a path
 143 suitable for LIBRARY, which includes \"../../etc/images\" and
 144 \"../etc/images\" relative to the library file itself, and then
 145 in \"`data-directory'/images\".
 146
 147 Then this function returns a list of directories which contains
 148 first the directory in which IMAGE was found, followed by the
 149 value of `load-path'. If PATH is given, it is used instead of
 150 `load-path'.
 151
 152 If NO-ERROR is non-nil and a suitable path can't be found, don't
 153 signal an error. Instead, return a list of directories as before,
 154 except that nil appears in place of the image directory.
 155
 156 Here is an example that uses a common idiom to provide
 157 compatibility with versions of Emacs that lack the variable
 158 `image-load-path':
 159
 160     ;; Shush compiler.
 161     (defvar image-load-path)
 162
 163     (let* ((load-path (image-load-path-for-library \"mh-e\" \"mh-logo.xpm\"))
 164            (image-load-path (cons (car load-path)
 165                                   (when (boundp 'image-load-path)
 166                                     image-load-path))))
 167       (mh-tool-bar-folder-buttons-init))"
 168   (unless library (error "No library specified"))
 169   (unless image   (error "No image specified"))
 170   (let (image-directory image-directory-load-path)
 171     ;; Check for images in image-load-path or load-path.
 172     (let ((img image)
 173           (dir (or
 174                 ;; Images in image-load-path.
 175                 (mh-image-search-load-path image)
 176                 ;; Images in load-path.
 177                 (locate-library image)))
 178           parent)
 179       ;; Since the image might be in a nested directory (for
 180       ;; example, mail/attach.pbm), adjust `image-directory'
 181       ;; accordingly.
 182       (when dir
 183         (setq dir (file-name-directory dir))
 184         (while (setq parent (file-name-directory img))
 185           (setq img (directory-file-name parent)
 186                 dir (expand-file-name "../" dir))))
 187       (setq image-directory-load-path dir))
 188
 189     ;; If `image-directory-load-path' isn't Emacs's image directory,
 190     ;; it's probably a user preference, so use it. Then use a
 191     ;; relative setting if possible; otherwise, use
 192     ;; `image-directory-load-path'.
 193     (cond
 194      ;; User-modified image-load-path?
 195      ((and image-directory-load-path
 196            (not (equal image-directory-load-path
 197                        (file-name-as-directory
 198                         (expand-file-name "images" data-directory)))))
 199       (setq image-directory image-directory-load-path))
 200      ;; Try relative setting.
 201      ((let (library-name d1ei d2ei)
 202         ;; First, find library in the load-path.
 203         (setq library-name (locate-library library))
 204         (if (not library-name)
 205             (error "Cannot find library %s in load-path" library))
 206         ;; And then set image-directory relative to that.
 207         (setq
 208          ;; Go down 2 levels.
 209          d2ei (file-name-as-directory
 210                (expand-file-name
 211                 (concat (file-name-directory library-name) "../../etc/images")))
 212          ;; Go down 1 level.
 213          d1ei (file-name-as-directory
 214                (expand-file-name
 215                 (concat (file-name-directory library-name) "../etc/images"))))
 216         (setq image-directory
 217               ;; Set it to nil if image is not found.
 218               (cond ((file-exists-p (expand-file-name image d2ei)) d2ei)
 219                     ((file-exists-p (expand-file-name image d1ei)) d1ei)))))
 220      ;; Use Emacs's image directory.
 221      (image-directory-load-path
 222       (setq image-directory image-directory-load-path))
 223      (no-error
 224       (message "Could not find image %s for library %s" image library))
 225      (t
 226       (error "Could not find image %s for library %s" image library)))
 227
 228     ;; Return an augmented `path' or `load-path'.
 229     (nconc (list image-directory)
 230            (delete image-directory (copy-sequence (or path load-path))))))
 231
 232 (defun-mh mh-image-search-load-path
 233   image-search-load-path (file &optional path)
 234   "Emacs 21 and XEmacs don't have `image-search-load-path'.
 235 This function returns nil on those systems."
 236   nil)
 237
 238 ;; For XEmacs.
 239 (defalias 'mh-line-beginning-position
 240   (if (fboundp 'line-beginning-position)
 241       'line-beginning-position
 242     'point-at-bol))
 243
 244 ;; For XEmacs.
 245 (defalias 'mh-line-end-position
 246   (if (fboundp 'line-end-position)
 247       'line-end-position
 248     'point-at-eol))
 249
 250 (mh-require 'mailabbrev nil t)
 251 (defun-mh mh-mail-abbrev-make-syntax-table
 252   mail-abbrev-make-syntax-table ()
 253   "Emacs 21 and XEmacs don't have `mail-abbrev-make-syntax-table'.
 254 This function returns nil on those systems."
 255   nil)
 256
 257 (defmacro mh-define-obsolete-variable-alias
 258   (obsolete-name current-name &optional when docstring)
 259   "Make OBSOLETE-NAME a variable alias for CURRENT-NAME and mark it obsolete.
 260 See documentation for `define-obsolete-variable-alias' for a description
 261 of the arguments OBSOLETE-NAME, CURRENT-NAME, and perhaps WHEN
 262 and DOCSTRING. This macro is used by XEmacs that lacks WHEN and
 263 DOCSTRING arguments."
 264   (if (featurep 'xemacs)
 265       `(define-obsolete-variable-alias ,obsolete-name ,current-name)
 266     `(define-obsolete-variable-alias ,obsolete-name ,current-name ,when ,docstring)))
 267
 268 (defmacro mh-make-obsolete-variable (obsolete-name current-name &optional when access-type)
 269   "Make the byte-compiler warn that OBSOLETE-NAME is obsolete.
 270 See documentation for `make-obsolete-variable' for a description
 271 of the arguments OBSOLETE-NAME, CURRENT-NAME, and perhaps WHEN
 272 and ACCESS-TYPE. This macro is used by XEmacs that lacks WHEN and
 273 ACCESS-TYPE arguments."
 274   (if (featurep 'xemacs)
 275       `(make-obsolete-variable ,obsolete-name ,current-name)
 276     `(make-obsolete-variable ,obsolete-name ,current-name ,when ,access-type)))
 277
 278 (defmacro mh-make-obsolete-variable (obsolete-name current-name &optional when access-type)
 279   "Make the byte-compiler warn that OBSOLETE-NAME is obsolete.
 280 See documentation for `make-obsolete-variable' for a description
 281 of the arguments OBSOLETE-NAME, CURRENT-NAME, and perhaps WHEN
 282 and ACCESS-TYPE. This macro is used by XEmacs that lacks WHEN and
 283 ACCESS-TYPE arguments and by Emacs versions that lack ACCESS-TYPE,
 284 introduced in Emacs 24."
 285   (if (featurep 'xemacs)
 286       `(make-obsolete-variable ,obsolete-name ,current-name)
 287     (if (< emacs-major-version 24)
 288         `(make-obsolete-variable ,obsolete-name ,current-name ,when)
 289       `(make-obsolete-variable ,obsolete-name ,current-name ,when ,access-type))))
 290
 291 (defun-mh mh-match-string-no-properties
 292   match-string-no-properties (num &optional string)
 293   "Return string of text matched by last search, without text properties.
 294 This function is used by XEmacs that lacks `match-string-no-properties'.
 295 The function `buffer-substring-no-properties' is used instead.
 296 The argument STRING is ignored."
 297   (buffer-substring-no-properties
 298    (match-beginning num) (match-end num)))
 299
 300 (defun-mh mh-replace-regexp-in-string replace-regexp-in-string
 301   (regexp rep string &optional fixedcase literal subexp start)
 302   "Replace REGEXP with REP everywhere in STRING and return result.
 303 This function is used by XEmacs that lacks `replace-regexp-in-string'.
 304 The function `replace-in-string' is used instead.
 305 The arguments FIXEDCASE, SUBEXP, and START, used by
 306 `replace-in-string' are ignored."
 307   (replace-in-string string regexp rep literal))
 308
 309 (defun-mh mh-test-completion
 310   test-completion (string collection &optional predicate)
 311   "Return non-nil if STRING is a valid completion.
 312 XEmacs does not have `test-completion'. This function returns nil
 313 on that system." nil)
 314
 315 ;; Copy of constant from url-util.el in Emacs 22; needed by Emacs 21.
 316 (if (not (boundp 'url-unreserved-chars))
 317     (defconst mh-url-unreserved-chars
 318       '(
 319         ?a ?b ?c ?d ?e ?f ?g ?h ?i ?j ?k ?l ?m ?n ?o ?p ?q ?r ?s ?t ?u ?v ?w ?x ?y ?z
 320         ?A ?B ?C ?D ?E ?F ?G ?H ?I ?J ?K ?L ?M ?N ?O ?P ?Q ?R ?S ?T ?U ?V ?W ?X ?Y ?Z
 321         ?0 ?1 ?2 ?3 ?4 ?5 ?6 ?7 ?8 ?9
 322         ?- ?_ ?. ?! ?~ ?* ?' ?\( ?\))
 323       "A list of characters that are _NOT_ reserved in the URL spec.
 324 This is taken from RFC 2396."))
 325
 326 (defun-mh mh-url-hexify-string url-hexify-string (str)
 327   "Escape characters in a string.
 328 This is a copy of `url-hexify-string' from url-util.el in Emacs
 329 22; needed by Emacs 21."
 330   (mapconcat
 331    (lambda (char)
 332      ;; Fixme: use a char table instead.
 333      (if (not (memq char mh-url-unreserved-chars))
 334          (if (> char 255)
 335                (error "Hexifying multibyte character %s" str)
 336            (format "%%%02X" char))
 337        (char-to-string char)))
 338    str ""))
 339
 340 (defun-mh mh-view-mode-enter
 341   view-mode-enter (&optional return-to exit-action)
 342   "Enter View mode.
 343 This function is used by XEmacs that lacks `view-mode-enter'.
 344 The function `view-mode' is used instead.
 345 The arguments RETURN-TO and EXIT-ACTION are ignored."
 346   ;; Shush compiler.
 347   (if return-to nil)
 348   (if exit-action nil)
 349   (view-mode 1))
 350
 351 (defun-mh mh-window-full-height-p
 352   window-full-height-p (&optional WINDOW)
 353   "Return non-nil if WINDOW is not the result of a vertical split.
 354 This function is defined in XEmacs as it lacks
 355 `window-full-height-p'. The values of the functions
 356 `window-height' and `frame-height' are compared instead. The
 357 argument WINDOW is ignored."
 358   (= (1+ (window-height))
 359      (frame-height)))
 360
 361 (defmacro mh-write-file-functions ()
 362   "Return `write-file-functions' if it exists.
 363 Otherwise return `local-write-file-hooks'.
 364 This macro exists purely for compatibility. The former symbol is used
 365 in Emacs 22 onward while the latter is used in previous versions and
 366 XEmacs."
 367   (if (boundp 'write-file-functions)
 368       ''write-file-functions            ;Emacs 22 on
 369     ''local-write-file-hooks))          ;XEmacs
 370
 371 (provide 'mh-compat)
 372
 373 ;; Local Variables:
 374 ;; no-byte-compile: t
 375 ;; indent-tabs-mode: nil
 376 ;; sentence-end-double-space: nil
 377 ;; End:
 378
 379 ;;; mh-compat.el ends here