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1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
a139f682 | 3 | @c Copyright (C) 1999, 2005 Free Software Foundation, Inc. |
0a9482c5 | 4 | @c See the file elisp.texi for copying conditions. |
46600ab1 GM |
5 | |
6 | @c This node must have no pointers. | |
7 | ||
e23a63a5 | 8 | @node Antinews, GNU Free Documentation License, System Interface, Top |
4b878354 | 9 | @appendix Emacs 21 Antinews |
0a9482c5 RS |
10 | |
11 | For those users who live backwards in time, here is information about | |
4b878354 RS |
12 | downgrading to Emacs version 21.4. We hope you will enjoy the greater |
13 | simplicity that results from the absence of many Emacs 22 features. | |
0a9482c5 | 14 | |
4b878354 | 15 | @section Old Lisp Features in Emacs 21 |
0a9482c5 RS |
16 | |
17 | @itemize @bullet | |
18 | @item | |
4b878354 RS |
19 | Many unnecessary features of redisplay have been eliminated. (The |
20 | earlier major release, Emacs 20, will have a completely rewritten | |
21 | redisplay engine, which will be even simpler.) | |
0a9482c5 | 22 | |
4b878354 | 23 | @itemize @minus |
0a9482c5 | 24 | @item |
4b878354 RS |
25 | The function @code{force-window-update} has been removed. It |
26 | shouldn't be needed, since changes in window contents are detected | |
27 | automatically. In case they aren't, call @code{redraw-display} to | |
28 | redraw everything. | |
0a9482c5 | 29 | |
0a9482c5 | 30 | @item |
4b878354 RS |
31 | Point no longer moves out from underneath invisible text at the end of |
32 | each command. This allows the user to detect invisible text by moving | |
33 | the cursor around---if the cursor gets stuck, there is something | |
34 | invisible in the way. If you really want cursor motion to ignore the | |
35 | text, try marking it as intangible. | |
0a9482c5 | 36 | |
6b5c0a2e | 37 | @item |
4b878354 RS |
38 | Support for image maps and image slices has been removed. Emacs was |
39 | always meant for editing text, anyway. | |
6b5c0a2e | 40 | |
0a9482c5 | 41 | @item |
4b878354 RS |
42 | The mode line now accepts all text properties, as well as |
43 | @code{:propertize} and @code{:eval} forms, regardless of the | |
44 | @code{risky-local-variable} property. | |
0a9482c5 | 45 | |
4b878354 RS |
46 | @item |
47 | The @code{line-height} and @code{line-spacing} properties no longer | |
48 | have any meaning for newline characters. Such properties wouldn't | |
49 | make sense, since newlines are not really characters; they just tell | |
50 | you where to break a line. | |
0a9482c5 | 51 | |
4b878354 RS |
52 | @item |
53 | Considerable simplifications have been made to the display | |
54 | specification @code{(space . @var{props})}, which is used for | |
55 | displaying a space of specified width and height. Pixel-based | |
56 | specifications and Lisp expressions are no longer accepted. | |
0a9482c5 | 57 | |
8241495d | 58 | @item |
4b878354 RS |
59 | Many features associated with the fringe areas have been removed, to |
60 | encourage people to concentrate on the main editing area (the fringe | |
61 | will be completely removed in Emacs 20.) Arbitrary bitmaps can no | |
62 | longer be displayed in the fringe; an overlay arrow can still be | |
63 | displayed, but there can only be one overlay arrow at a time (any more | |
64 | would be confusing.) The fringe widths cannot be adjusted, and | |
65 | individual windows cannot have their own fringe settings. A mouse | |
66 | click on the fringe no longer generates a special event. | |
6b5c0a2e | 67 | |
1dffc5db | 68 | @item |
4b878354 | 69 | Individual windows cannot have their own scroll-bar settings. |
1dffc5db | 70 | |
6b5c0a2e | 71 | @item |
4b878354 RS |
72 | You can no longer use @samp{default} in a @code{defface} to specify |
73 | defaults for subsequent faces. | |
0a9482c5 | 74 | |
1dffc5db | 75 | @item |
4b878354 RS |
76 | The function @code{display-supports-face-attributes-p} has been |
77 | removed. In @code{defface} specifications, the @code{supports} | |
78 | predicate is no longer supported. | |
1dffc5db RS |
79 | |
80 | @item | |
4b878354 RS |
81 | @code{face-attribute-relative-p} and @code{merge-face-attribute} have |
82 | been removed. | |
1dffc5db | 83 | |
0a9482c5 | 84 | @item |
4b878354 RS |
85 | The priority of faces in a list supplied by the @code{:inherit} face |
86 | attribute has been reversed. We like to make changes like this once | |
87 | in a while, to keep Emacs Lisp programmers on their toes. | |
0a9482c5 RS |
88 | |
89 | @item | |
4b878354 RS |
90 | The @code{min-colors} face attribute, used for tailoring faces to |
91 | limited-color displays, does not exist. If in doubt, use colors like | |
92 | ``white'' and ``black'', which ought to be defined everywhere. | |
0a9482c5 RS |
93 | |
94 | @item | |
4b878354 RS |
95 | The @code{tty-color-mode} frame parameter does not exist. You should |
96 | just trust the terminal capabilities database. | |
97 | @end itemize | |
0a9482c5 RS |
98 | |
99 | @item | |
4b878354 | 100 | Several simplifications have been made to mouse support: |
0a9482c5 | 101 | |
4b878354 | 102 | @itemize @minus |
0a9482c5 | 103 | @item |
4b878354 RS |
104 | Clicking @kbd{mouse-1} won't follow links, as that is alien to the |
105 | spirit of Emacs. Therefore, the @code{follow-link} property doesn't | |
106 | has any special meaning, and the function @code{mouse-on-link-p} has | |
107 | been removed. | |
0a9482c5 | 108 | |
1dffc5db | 109 | @item |
4b878354 RS |
110 | The variable @code{void-text-area-pointer} has been removed, so the |
111 | mouse pointer shape remains unchanged when moving between valid text | |
112 | areas and void text areas. The @code{pointer} image and text | |
113 | properties are no longer supported. | |
1dffc5db RS |
114 | |
115 | @item | |
4b878354 RS |
116 | Mouse events will no longer specify the timestamp, the object clicked, |
117 | equivalent buffer positions (for marginal or fringe areas), glyph | |
118 | coordinates, or relative pixel coordinates. | |
119 | @end itemize | |
1dffc5db | 120 | |
6b5c0a2e | 121 | @item |
4b878354 RS |
122 | Simplifications have also been made to the way Emacs handles keymaps |
123 | and key sequences: | |
6b5c0a2e | 124 | |
4b878354 | 125 | @itemize @minus |
0a9482c5 | 126 | @item |
4b878354 RS |
127 | The @code{kbd} macro has been removed. It isn't that difficult to |
128 | write key sequences using the string and vector representations, and | |
129 | we want to encourage users to learn. | |
0a9482c5 RS |
130 | |
131 | @item | |
4b878354 RS |
132 | Emacs no longer supports key remapping. You can do pretty much the |
133 | same thing with @code{substitute-key-definition}, or by advising the | |
134 | relevant command. | |
0a9482c5 RS |
135 | |
136 | @item | |
4b878354 RS |
137 | The @code{keymap} text and overlay property is now overridden by minor |
138 | mode keymaps, and will not work at the ends of text properties and | |
139 | overlays. | |
0a9482c5 RS |
140 | |
141 | @item | |
4b878354 RS |
142 | The functions @code{map-keymap}, @code{keymap-prompt}, and |
143 | @code{current-active-maps} have been removed. | |
144 | @end itemize | |
0a9482c5 | 145 | |
8241495d | 146 | @item |
4b878354 RS |
147 | Process support has been pared down to a functional minimum. The |
148 | functions @code{call-process-shell-command} and @code{process-file} | |
149 | have been deleted. Processes no longer maintain property lists, and | |
150 | they won't ask any questions when the user tries to exit Emacs (which | |
151 | would simply be rude.) The function @code{signal-process} won't | |
152 | accept a process object, only the process id; determining the process | |
153 | id from a process object is left as an exercise to the programmer. | |
0a9482c5 | 154 | |
574efc83 | 155 | @item |
4b878354 RS |
156 | Networking has also been simplified: @code{make-network-process} and |
157 | its various associated function have all been replaced with a single | |
158 | easy-to-use function, @code{open-network-stream}, which can't use UDP, | |
159 | can't act as a server, and can't set up non-blocking connections. | |
160 | Also, deleting a network process with @code{delete-process} won't call | |
161 | the sentinel. | |
0a9482c5 | 162 | |
1dffc5db | 163 | @item |
4b878354 RS |
164 | Many programming shortcuts have been deleted, to provide you with the |
165 | enjoyment of ``rolling your own''. The macros @code{while-no-input}, | |
166 | @code{with-local-quit}, @code{with-selected-window}, | |
167 | @code{dynamic-completion-table}, and @code{lazy-completion-table} no | |
168 | longer exist. Also, there are no built-in progress reporters. | |
1dffc5db | 169 | |
574efc83 | 170 | @item |
4b878354 RS |
171 | Variable aliases are no longer supported. Aliases are for functions, |
172 | not for variables. | |
0a9482c5 | 173 | |
574efc83 | 174 | @item |
4b878354 RS |
175 | The variables @code{most-positive-fixnum} and |
176 | @code{most-negative-fixnum} do not exist. On 32 bit machines, the | |
177 | most positive integer is probably 134217727, and the most negative | |
178 | integer is probably -134217728. | |
0a9482c5 | 179 | |
0a9482c5 | 180 | @item |
4b878354 RS |
181 | The functions @code{eql} and @code{macroexpand-all} are no longer |
182 | available. However, you can find similar functions in the @code{cl} | |
183 | package. | |
0a9482c5 | 184 | |
a40d4712 | 185 | @item |
4b878354 RS |
186 | The list returned by @code{split-string} won't include null substrings |
187 | for separators at the beginning or end of a string. If you want to | |
188 | check for such separators, do it separately. | |
a40d4712 | 189 | |
0a9482c5 | 190 | @item |
4b878354 RS |
191 | The function @code{assoc-string} has been removed. Use |
192 | @code{assoc-ignore-case} or @code{assoc-ignore-representation} (which | |
193 | are no longer obsolete.) | |
0a9482c5 RS |
194 | |
195 | @item | |
4b878354 RS |
196 | The escape sequence @samp{\s} is always interpreted as a super |
197 | modifier, never a space. | |
0a9482c5 | 198 | |
ec221d13 | 199 | @item |
4b878354 RS |
200 | The variable @code{buffer-save-without-query} has been removed, to |
201 | prevent Emacs from sneakily saving buffers. Also, the hook | |
202 | @code{before-save-hook} has been removed, so if you want something to | |
203 | be done before saving, advise or redefine @code{basic-save-buffer}. | |
0a9482c5 | 204 | |
ec221d13 | 205 | @item |
4b878354 RS |
206 | The variable @code{buffer-auto-save-file-format} has been renamed to |
207 | @code{auto-save-file-format}, and is no longer a permanent local. | |
0a9482c5 | 208 | |
390538c3 | 209 | @item |
4b878354 RS |
210 | The function @code{visited-file-modtime} now returns a cons, instead |
211 | of a list of two integers. The primitive @code{set-file-times} has | |
212 | been eliminated. | |
390538c3 | 213 | |
0a9482c5 | 214 | @item |
4b878354 | 215 | The function @code{file-remote-p} is no longer available. |
0a9482c5 RS |
216 | |
217 | @item | |
4b878354 RS |
218 | When determining the filename extension, a leading dot in a filename |
219 | is no longer ignored. Thus, @file{.emacs} is considered to have | |
220 | extension @file{emacs}, rather than being extensionless. | |
fcad2463 RS |
221 | |
222 | @item | |
4b878354 RS |
223 | Emacs looks for special file handlers in a more efficient manner: it |
224 | will choose the first matching handler in | |
225 | @code{file-name-handler-alist}, rather than trying to figure out which | |
226 | provides the closest match. | |
0a9482c5 | 227 | |
969fe9b5 | 228 | @item |
4b878354 RS |
229 | The @code{predicate} argument for @code{read-file-name} has been |
230 | removed, and so have the variables @code{read-file-name-function} and | |
231 | @code{read-file-name-completion-ignore-case}. The function | |
232 | @code{read-directory-name} has also been removed. | |
969fe9b5 | 233 | |
0a9482c5 | 234 | @item |
4b878354 RS |
235 | The functions @code{all-completions} and @code{try-completion} will no |
236 | longer accept lists of strings or hash tables (it will still accept | |
237 | alists, obarrays, and functions.) In addition, the function | |
238 | @code{test-completion} is no longer available. | |
0a9482c5 RS |
239 | |
240 | @item | |
4b878354 RS |
241 | Arbitrary Lisp functions can no longer be recorded into |
242 | @code{buffer-undo-list}. As a consequence, @code{yank-undo-function} | |
243 | is obsolete, and has been removed. | |
0a9482c5 RS |
244 | |
245 | @item | |
4b878354 RS |
246 | Emacs will never complain about commands that accumulate too much undo |
247 | information, so you no longer have to worry about binding | |
248 | @code{buffer-undo-list} to @code{t} for such commands (though you may | |
249 | want to do that anyway, to avoid taking up unnecessary memory space.) | |
0a9482c5 | 250 | |
4b878354 RS |
251 | @item |
252 | Atomic change groups are no longer supported. | |
0a9482c5 | 253 | |
4b878354 RS |
254 | @item |
255 | The list returned by @code{(match-data t)} no longer records the | |
256 | buffer as a final element. | |
0a9482c5 | 257 | |
4b878354 RS |
258 | @item |
259 | The function @code{looking-back} has been removed, so we no longer | |
260 | have the benefit of hindsight. | |
0a9482c5 RS |
261 | |
262 | @item | |
4b878354 RS |
263 | The variable @code{search-spaces-regexp} does not exist. Spaces |
264 | always stand for themselves in regular expression searches. | |
0a9482c5 RS |
265 | |
266 | @item | |
4b878354 RS |
267 | The functions @code{skip-chars-forward} and @code{skip-chars-backward} |
268 | no longer accepts character classes such as @samp{[:alpha:]}. All | |
269 | characters are created equal. | |
0a9482c5 RS |
270 | |
271 | @item | |
4b878354 RS |
272 | The @code{yank-handler} text property no longer has any meaning. |
273 | Also, @code{yank-excluded-properties}, @code{insert-for-yank}, and | |
274 | @code{insert-buffer-substring-as-yank} have all been removed. | |
0a9482c5 RS |
275 | |
276 | @item | |
4b878354 RS |
277 | The variable @code{char-property-alias-alist} has been deleted. |
278 | Aliases are for functions, not for properties. | |
0a9482c5 RS |
279 | |
280 | @item | |
4b878354 RS |
281 | The function @code{get-char-property-and-overlay} has been deleted. |
282 | If you want the properties at a point, find the text properties at the | |
283 | point; then, find the overlays at the point, and find the properties | |
284 | on those overlays. | |
0a9482c5 RS |
285 | |
286 | @item | |
4b878354 RS |
287 | Font Lock mode only manages @code{face} properties; you can't use |
288 | font-lock keywords to specify arbitrary text properties for it to | |
289 | manage. After all, it is called Font Lock mode, not Arbitrary | |
290 | Properties Lock mode. | |
0a9482c5 | 291 | |
574efc83 | 292 | @item |
4b878354 | 293 | The arguments to @code{remove-overlays} are no longer optional. |
0a9482c5 | 294 | |
574efc83 | 295 | @item |
4b878354 RS |
296 | In @code{replace-match}, the replacement text now inherits properties |
297 | from the surrounding text. | |
0a9482c5 | 298 | |
574efc83 | 299 | @item |
4b878354 RS |
300 | @code{mode-line-format} no longer supports the @code{:propertize}, |
301 | @code{%i}, and @code{%I} constructs. The function | |
302 | @code{format-mode-line} has been removed. | |
0a9482c5 | 303 | |
574efc83 | 304 | @item |
4b878354 RS |
305 | The functions @code{window-inside-edges} and @code{window-body-height} |
306 | have been removed. You should do the relevant calculations yourself, | |
307 | starting with @code{window-width} and @code{window-height}. | |
0a9482c5 | 308 | |
0a9482c5 | 309 | @item |
4b878354 RS |
310 | The functions @code{window-pixel-edges} and |
311 | @code{window-inside-pixel-edges} have been removed. We prefer to | |
312 | think in terms of lines and columns, not pixel coordinates. (Sometime | |
313 | in the distant past, we will do away with graphical terminals | |
314 | entirely, in favor of text terminals.) For similar reasons, the | |
315 | functions @code{posn-at-point}, @code{posn-at-x-y}, and | |
316 | @code{pos-visible-in-window-p} have been removed. | |
0a9482c5 RS |
317 | |
318 | @item | |
4b878354 RS |
319 | The macro @code{save-selected-window} only saves the selected window |
320 | of the selected frame, so don't try selecting windows in other frames. | |
0a9482c5 RS |
321 | |
322 | @item | |
4b878354 | 323 | The function @code{minibufferp} is no longer available. |
0a9482c5 RS |
324 | |
325 | @item | |
4b878354 RS |
326 | The function @code{modify-all-frames-parameters} has been removed (we |
327 | always suspected the name was ungrammatical, anyway.) | |
328 | ||
329 | @item | |
330 | The @code{line-spacing} variable no longer accepts float values. | |
331 | ||
332 | @item | |
333 | The function @code{tool-bar-local-item-from-menu} has been deleted. | |
334 | If you need to make an entry in the tool bar, you can still use | |
335 | @code{tool-bar-add-item-from-menu}, but that modifies the binding in | |
336 | the source keymap instead of copying it into the local keymap. | |
337 | ||
338 | @item | |
339 | When determining the major mode, the file name takes precedence over | |
340 | the interpreter magic line. The variable @code{magic-mode-alist}, | |
341 | which associates certain buffer beginnings with major modes, has been | |
342 | eliminated. | |
343 | ||
344 | @item | |
345 | The hook @code{after-change-major-mode-hook} is not defined, and | |
346 | neither are @code{run-mode-hooks} and @code{delay-mode-hooks}. | |
347 | ||
348 | @item | |
349 | The variable @code{minor-mode-list} has been removed. | |
350 | ||
351 | @item | |
352 | @code{define-derived-mode} will copy abbrevs from the parent mode's | |
353 | abbrev table, instead of creating a new, empty abbrev table. | |
354 | ||
355 | @item | |
356 | There are no ``system'' abbrevs. When the user saves into the abbrevs | |
357 | file, all abbrevs are saved. | |
358 | ||
359 | @item | |
360 | The Warnings facility has been removed. Just use @code{error}. | |
361 | ||
362 | @item | |
363 | Several hook variables have been renamed to flout the Emacs naming | |
364 | conventions. We feel that consistency is boring, and having | |
365 | non-standard hook names encourages users to check the documentation | |
366 | before using a hook. For instance, the normal hook | |
367 | @code{find-file-hook} has been renamed to @code{find-file-hooks}, and | |
368 | the abnormal hook @code{delete-frame-functions} has been renamed to | |
369 | @code{delete-frame-hook}. | |
370 | ||
371 | @item | |
372 | The function @code{symbol-file} does not exist. If you want to know | |
373 | which file defined a function or variable, try grepping for it. | |
374 | ||
375 | @item | |
376 | The variable @code{load-history} records function definitions just | |
377 | like variable definitions, instead of indicating which functions were | |
378 | previously autoloaded. | |
379 | ||
380 | @item | |
381 | There is a new variable, @code{recursive-load-depth-limit}, which | |
382 | specifies how many times files can recursively load themselves; it is | |
383 | 50 by default, and nil means infinity. Previously, Emacs signalled an | |
384 | error after just 3 recursive loads, which was boring. | |
385 | ||
386 | @item | |
387 | Byte-compiler warnings and error messages will leave out the line and | |
388 | character positions, in order to exercise your debugging skills. | |
389 | Also, there is no @code{with-no-warnings} macro---instead of | |
390 | suppressing compiler warnings, fix your code to avoid them! | |
391 | ||
392 | @item | |
393 | The function @code{unsafep} has been removed. | |
394 | ||
395 | @item | |
396 | File local variables can now specify a string with text properties. | |
397 | Since arbitrary Lisp expressions can be embedded in text properties, | |
398 | this can provide you with a great deal of flexibility and power. On | |
399 | the other hand, @code{safe-local-eval-forms} and the | |
400 | @code{safe-local-eval-function} function property have no special | |
8241495d | 401 | meaning. |
0a9482c5 RS |
402 | |
403 | @item | |
4b878354 RS |
404 | You can no longer use @code{char-displayable-p} to test if Emacs can |
405 | display a certain character. | |
406 | ||
407 | @item | |
408 | The function @code{string-to-multibyte} is no longer available. | |
409 | ||
410 | @item | |
411 | The @code{translation-table-for-input} translation table has been | |
412 | removed. Also, translation hash tables are no longer available, so we | |
413 | don't need the functions @code{lookup-character} and | |
414 | @code{lookup-integer}. | |
415 | ||
416 | @item | |
417 | The @code{table} argument to @code{translate-region} can no longer be | |
418 | a char-table; it has to be a string. | |
419 | ||
420 | @item | |
421 | The functions @code{merge-coding-systems} and | |
422 | @code{decode-coding-inserted-region}, and the variable | |
423 | @code{auto-coding-functions}, have been deleted. The | |
424 | @code{mime-text-unsuitable} coding system property no longer has any | |
425 | special meaning. | |
0a9482c5 RS |
426 | |
427 | @item | |
4b878354 RS |
428 | If pure storage overflows while dumping, Emacs won't tell you how much |
429 | additional pure storage it needs. Try adding in increments of 20000, | |
430 | until you have enough. | |
0a9482c5 RS |
431 | |
432 | @item | |
4b878354 RS |
433 | The variables @code{gc-elapsed}, @code{gcs-done}, and |
434 | @code{post-gc-hook} have been garbage-collected. | |
0a9482c5 | 435 | @end itemize |
ab5796a9 MB |
436 | |
437 | @ignore | |
438 | arch-tag: 1d0ef137-2bad-430e-ae8e-d820d569b5a6 | |
439 | @end ignore |