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1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
ceb4c4d3 TTN |
3 | @c Copyright (C) 1999, 2002, 2003, 2004, 2005, |
4 | @c 2006 Free Software Foundation, Inc. | |
0a9482c5 | 5 | @c See the file elisp.texi for copying conditions. |
46600ab1 GM |
6 | |
7 | @c This node must have no pointers. | |
8 | ||
e23a63a5 | 9 | @node Antinews, GNU Free Documentation License, System Interface, Top |
4b878354 | 10 | @appendix Emacs 21 Antinews |
0a9482c5 RS |
11 | |
12 | For those users who live backwards in time, here is information about | |
4b878354 | 13 | downgrading to Emacs version 21.4. We hope you will enjoy the greater |
0b3a2969 LK |
14 | simplicity that results from the absence of many Emacs @value{EMACSVER} |
15 | features. | |
0a9482c5 | 16 | |
4b878354 | 17 | @section Old Lisp Features in Emacs 21 |
0a9482c5 RS |
18 | |
19 | @itemize @bullet | |
20 | @item | |
4b878354 RS |
21 | Many unnecessary features of redisplay have been eliminated. (The |
22 | earlier major release, Emacs 20, will have a completely rewritten | |
23 | redisplay engine, which will be even simpler.) | |
0a9482c5 | 24 | |
4b878354 | 25 | @itemize @minus |
0a9482c5 | 26 | @item |
4b878354 RS |
27 | The function @code{force-window-update} has been removed. It |
28 | shouldn't be needed, since changes in window contents are detected | |
29 | automatically. In case they aren't, call @code{redraw-display} to | |
30 | redraw everything. | |
0a9482c5 | 31 | |
0a9482c5 | 32 | @item |
4b878354 RS |
33 | Point no longer moves out from underneath invisible text at the end of |
34 | each command. This allows the user to detect invisible text by moving | |
35 | the cursor around---if the cursor gets stuck, there is something | |
36 | invisible in the way. If you really want cursor motion to ignore the | |
37 | text, try marking it as intangible. | |
0a9482c5 | 38 | |
6b5c0a2e | 39 | @item |
4b878354 RS |
40 | Support for image maps and image slices has been removed. Emacs was |
41 | always meant for editing text, anyway. | |
6b5c0a2e | 42 | |
0a9482c5 | 43 | @item |
4b878354 RS |
44 | The mode line now accepts all text properties, as well as |
45 | @code{:propertize} and @code{:eval} forms, regardless of the | |
46 | @code{risky-local-variable} property. | |
0a9482c5 | 47 | |
4b878354 RS |
48 | @item |
49 | The @code{line-height} and @code{line-spacing} properties no longer | |
50 | have any meaning for newline characters. Such properties wouldn't | |
51 | make sense, since newlines are not really characters; they just tell | |
52 | you where to break a line. | |
0a9482c5 | 53 | |
4b878354 RS |
54 | @item |
55 | Considerable simplifications have been made to the display | |
56 | specification @code{(space . @var{props})}, which is used for | |
57 | displaying a space of specified width and height. Pixel-based | |
58 | specifications and Lisp expressions are no longer accepted. | |
0a9482c5 | 59 | |
8241495d | 60 | @item |
4b878354 RS |
61 | Many features associated with the fringe areas have been removed, to |
62 | encourage people to concentrate on the main editing area (the fringe | |
63 | will be completely removed in Emacs 20.) Arbitrary bitmaps can no | |
64 | longer be displayed in the fringe; an overlay arrow can still be | |
65 | displayed, but there can only be one overlay arrow at a time (any more | |
66 | would be confusing.) The fringe widths cannot be adjusted, and | |
67 | individual windows cannot have their own fringe settings. A mouse | |
68 | click on the fringe no longer generates a special event. | |
6b5c0a2e | 69 | |
1dffc5db | 70 | @item |
4b878354 | 71 | Individual windows cannot have their own scroll-bar settings. |
1dffc5db | 72 | |
6b5c0a2e | 73 | @item |
4b878354 RS |
74 | You can no longer use @samp{default} in a @code{defface} to specify |
75 | defaults for subsequent faces. | |
0a9482c5 | 76 | |
1dffc5db | 77 | @item |
4b878354 RS |
78 | The function @code{display-supports-face-attributes-p} has been |
79 | removed. In @code{defface} specifications, the @code{supports} | |
80 | predicate is no longer supported. | |
1dffc5db RS |
81 | |
82 | @item | |
4b878354 RS |
83 | @code{face-attribute-relative-p} and @code{merge-face-attribute} have |
84 | been removed. | |
1dffc5db | 85 | |
0a9482c5 | 86 | @item |
4b878354 RS |
87 | The priority of faces in a list supplied by the @code{:inherit} face |
88 | attribute has been reversed. We like to make changes like this once | |
89 | in a while, to keep Emacs Lisp programmers on their toes. | |
0a9482c5 RS |
90 | |
91 | @item | |
4b878354 RS |
92 | The @code{min-colors} face attribute, used for tailoring faces to |
93 | limited-color displays, does not exist. If in doubt, use colors like | |
94 | ``white'' and ``black'', which ought to be defined everywhere. | |
0a9482c5 RS |
95 | |
96 | @item | |
4b878354 RS |
97 | The @code{tty-color-mode} frame parameter does not exist. You should |
98 | just trust the terminal capabilities database. | |
99 | @end itemize | |
0a9482c5 RS |
100 | |
101 | @item | |
4b878354 | 102 | Several simplifications have been made to mouse support: |
0a9482c5 | 103 | |
4b878354 | 104 | @itemize @minus |
0a9482c5 | 105 | @item |
4b878354 RS |
106 | Clicking @kbd{mouse-1} won't follow links, as that is alien to the |
107 | spirit of Emacs. Therefore, the @code{follow-link} property doesn't | |
108 | has any special meaning, and the function @code{mouse-on-link-p} has | |
109 | been removed. | |
0a9482c5 | 110 | |
1dffc5db | 111 | @item |
4b878354 RS |
112 | The variable @code{void-text-area-pointer} has been removed, so the |
113 | mouse pointer shape remains unchanged when moving between valid text | |
114 | areas and void text areas. The @code{pointer} image and text | |
115 | properties are no longer supported. | |
1dffc5db RS |
116 | |
117 | @item | |
4b878354 RS |
118 | Mouse events will no longer specify the timestamp, the object clicked, |
119 | equivalent buffer positions (for marginal or fringe areas), glyph | |
120 | coordinates, or relative pixel coordinates. | |
121 | @end itemize | |
1dffc5db | 122 | |
6b5c0a2e | 123 | @item |
4b878354 RS |
124 | Simplifications have also been made to the way Emacs handles keymaps |
125 | and key sequences: | |
6b5c0a2e | 126 | |
4b878354 | 127 | @itemize @minus |
0a9482c5 | 128 | @item |
4b878354 RS |
129 | The @code{kbd} macro has been removed. It isn't that difficult to |
130 | write key sequences using the string and vector representations, and | |
131 | we want to encourage users to learn. | |
0a9482c5 RS |
132 | |
133 | @item | |
4b878354 RS |
134 | Emacs no longer supports key remapping. You can do pretty much the |
135 | same thing with @code{substitute-key-definition}, or by advising the | |
136 | relevant command. | |
0a9482c5 RS |
137 | |
138 | @item | |
4b878354 RS |
139 | The @code{keymap} text and overlay property is now overridden by minor |
140 | mode keymaps, and will not work at the ends of text properties and | |
141 | overlays. | |
0a9482c5 RS |
142 | |
143 | @item | |
4b878354 RS |
144 | The functions @code{map-keymap}, @code{keymap-prompt}, and |
145 | @code{current-active-maps} have been removed. | |
146 | @end itemize | |
0a9482c5 | 147 | |
8241495d | 148 | @item |
4b878354 RS |
149 | Process support has been pared down to a functional minimum. The |
150 | functions @code{call-process-shell-command} and @code{process-file} | |
151 | have been deleted. Processes no longer maintain property lists, and | |
152 | they won't ask any questions when the user tries to exit Emacs (which | |
153 | would simply be rude.) The function @code{signal-process} won't | |
154 | accept a process object, only the process id; determining the process | |
155 | id from a process object is left as an exercise to the programmer. | |
0a9482c5 | 156 | |
574efc83 | 157 | @item |
4b878354 RS |
158 | Networking has also been simplified: @code{make-network-process} and |
159 | its various associated function have all been replaced with a single | |
160 | easy-to-use function, @code{open-network-stream}, which can't use UDP, | |
161 | can't act as a server, and can't set up non-blocking connections. | |
162 | Also, deleting a network process with @code{delete-process} won't call | |
163 | the sentinel. | |
0a9482c5 | 164 | |
1dffc5db | 165 | @item |
4b878354 RS |
166 | Many programming shortcuts have been deleted, to provide you with the |
167 | enjoyment of ``rolling your own''. The macros @code{while-no-input}, | |
72b09a92 RS |
168 | @code{with-local-quit}, and @code{with-selected-window}, along with |
169 | @code{dynamic-completion-table} and @code{lazy-completion-table} no | |
170 | longer exist. Also, there are no built-in progress reporters; | |
171 | with Emacs, you can take progress for granted. | |
1dffc5db | 172 | |
574efc83 | 173 | @item |
4b878354 RS |
174 | Variable aliases are no longer supported. Aliases are for functions, |
175 | not for variables. | |
0a9482c5 | 176 | |
574efc83 | 177 | @item |
4b878354 RS |
178 | The variables @code{most-positive-fixnum} and |
179 | @code{most-negative-fixnum} do not exist. On 32 bit machines, the | |
180 | most positive integer is probably 134217727, and the most negative | |
181 | integer is probably -134217728. | |
0a9482c5 | 182 | |
0a9482c5 | 183 | @item |
4b878354 RS |
184 | The functions @code{eql} and @code{macroexpand-all} are no longer |
185 | available. However, you can find similar functions in the @code{cl} | |
186 | package. | |
0a9482c5 | 187 | |
a40d4712 | 188 | @item |
4b878354 RS |
189 | The list returned by @code{split-string} won't include null substrings |
190 | for separators at the beginning or end of a string. If you want to | |
191 | check for such separators, do it separately. | |
a40d4712 | 192 | |
0a9482c5 | 193 | @item |
4b878354 RS |
194 | The function @code{assoc-string} has been removed. Use |
195 | @code{assoc-ignore-case} or @code{assoc-ignore-representation} (which | |
196 | are no longer obsolete.) | |
0a9482c5 RS |
197 | |
198 | @item | |
4b878354 RS |
199 | The escape sequence @samp{\s} is always interpreted as a super |
200 | modifier, never a space. | |
0a9482c5 | 201 | |
ec221d13 | 202 | @item |
4b878354 RS |
203 | The variable @code{buffer-save-without-query} has been removed, to |
204 | prevent Emacs from sneakily saving buffers. Also, the hook | |
205 | @code{before-save-hook} has been removed, so if you want something to | |
206 | be done before saving, advise or redefine @code{basic-save-buffer}. | |
0a9482c5 | 207 | |
ec221d13 | 208 | @item |
4b878354 RS |
209 | The variable @code{buffer-auto-save-file-format} has been renamed to |
210 | @code{auto-save-file-format}, and is no longer a permanent local. | |
0a9482c5 | 211 | |
390538c3 | 212 | @item |
4b878354 RS |
213 | The function @code{visited-file-modtime} now returns a cons, instead |
214 | of a list of two integers. The primitive @code{set-file-times} has | |
215 | been eliminated. | |
390538c3 | 216 | |
0a9482c5 | 217 | @item |
4b878354 | 218 | The function @code{file-remote-p} is no longer available. |
0a9482c5 RS |
219 | |
220 | @item | |
4b878354 RS |
221 | When determining the filename extension, a leading dot in a filename |
222 | is no longer ignored. Thus, @file{.emacs} is considered to have | |
223 | extension @file{emacs}, rather than being extensionless. | |
fcad2463 RS |
224 | |
225 | @item | |
4b878354 RS |
226 | Emacs looks for special file handlers in a more efficient manner: it |
227 | will choose the first matching handler in | |
228 | @code{file-name-handler-alist}, rather than trying to figure out which | |
229 | provides the closest match. | |
0a9482c5 | 230 | |
969fe9b5 | 231 | @item |
4b878354 RS |
232 | The @code{predicate} argument for @code{read-file-name} has been |
233 | removed, and so have the variables @code{read-file-name-function} and | |
234 | @code{read-file-name-completion-ignore-case}. The function | |
235 | @code{read-directory-name} has also been removed. | |
969fe9b5 | 236 | |
0a9482c5 | 237 | @item |
4b878354 RS |
238 | The functions @code{all-completions} and @code{try-completion} will no |
239 | longer accept lists of strings or hash tables (it will still accept | |
240 | alists, obarrays, and functions.) In addition, the function | |
241 | @code{test-completion} is no longer available. | |
0a9482c5 | 242 | |
1d748512 RS |
243 | @item |
244 | The @samp{G} interactive code character is no longer supported. | |
245 | Use @samp{F} instead. | |
246 | ||
0a9482c5 | 247 | @item |
4b878354 RS |
248 | Arbitrary Lisp functions can no longer be recorded into |
249 | @code{buffer-undo-list}. As a consequence, @code{yank-undo-function} | |
250 | is obsolete, and has been removed. | |
0a9482c5 RS |
251 | |
252 | @item | |
4b878354 RS |
253 | Emacs will never complain about commands that accumulate too much undo |
254 | information, so you no longer have to worry about binding | |
255 | @code{buffer-undo-list} to @code{t} for such commands (though you may | |
256 | want to do that anyway, to avoid taking up unnecessary memory space.) | |
0a9482c5 | 257 | |
4b878354 RS |
258 | @item |
259 | Atomic change groups are no longer supported. | |
0a9482c5 | 260 | |
4b878354 RS |
261 | @item |
262 | The list returned by @code{(match-data t)} no longer records the | |
263 | buffer as a final element. | |
0a9482c5 | 264 | |
4b878354 RS |
265 | @item |
266 | The function @code{looking-back} has been removed, so we no longer | |
267 | have the benefit of hindsight. | |
0a9482c5 RS |
268 | |
269 | @item | |
4b878354 RS |
270 | The variable @code{search-spaces-regexp} does not exist. Spaces |
271 | always stand for themselves in regular expression searches. | |
0a9482c5 RS |
272 | |
273 | @item | |
4b878354 RS |
274 | The functions @code{skip-chars-forward} and @code{skip-chars-backward} |
275 | no longer accepts character classes such as @samp{[:alpha:]}. All | |
276 | characters are created equal. | |
0a9482c5 RS |
277 | |
278 | @item | |
4b878354 RS |
279 | The @code{yank-handler} text property no longer has any meaning. |
280 | Also, @code{yank-excluded-properties}, @code{insert-for-yank}, and | |
281 | @code{insert-buffer-substring-as-yank} have all been removed. | |
0a9482c5 RS |
282 | |
283 | @item | |
4b878354 RS |
284 | The variable @code{char-property-alias-alist} has been deleted. |
285 | Aliases are for functions, not for properties. | |
0a9482c5 RS |
286 | |
287 | @item | |
4b878354 RS |
288 | The function @code{get-char-property-and-overlay} has been deleted. |
289 | If you want the properties at a point, find the text properties at the | |
290 | point; then, find the overlays at the point, and find the properties | |
291 | on those overlays. | |
0a9482c5 RS |
292 | |
293 | @item | |
4b878354 RS |
294 | Font Lock mode only manages @code{face} properties; you can't use |
295 | font-lock keywords to specify arbitrary text properties for it to | |
296 | manage. After all, it is called Font Lock mode, not Arbitrary | |
297 | Properties Lock mode. | |
0a9482c5 | 298 | |
574efc83 | 299 | @item |
4b878354 | 300 | The arguments to @code{remove-overlays} are no longer optional. |
0a9482c5 | 301 | |
574efc83 | 302 | @item |
4b878354 RS |
303 | In @code{replace-match}, the replacement text now inherits properties |
304 | from the surrounding text. | |
0a9482c5 | 305 | |
574efc83 | 306 | @item |
4b878354 RS |
307 | @code{mode-line-format} no longer supports the @code{:propertize}, |
308 | @code{%i}, and @code{%I} constructs. The function | |
309 | @code{format-mode-line} has been removed. | |
0a9482c5 | 310 | |
574efc83 | 311 | @item |
4b878354 RS |
312 | The functions @code{window-inside-edges} and @code{window-body-height} |
313 | have been removed. You should do the relevant calculations yourself, | |
314 | starting with @code{window-width} and @code{window-height}. | |
0a9482c5 | 315 | |
0a9482c5 | 316 | @item |
4b878354 RS |
317 | The functions @code{window-pixel-edges} and |
318 | @code{window-inside-pixel-edges} have been removed. We prefer to | |
319 | think in terms of lines and columns, not pixel coordinates. (Sometime | |
320 | in the distant past, we will do away with graphical terminals | |
321 | entirely, in favor of text terminals.) For similar reasons, the | |
322 | functions @code{posn-at-point}, @code{posn-at-x-y}, and | |
323 | @code{pos-visible-in-window-p} have been removed. | |
0a9482c5 RS |
324 | |
325 | @item | |
4b878354 RS |
326 | The macro @code{save-selected-window} only saves the selected window |
327 | of the selected frame, so don't try selecting windows in other frames. | |
0a9482c5 RS |
328 | |
329 | @item | |
4b878354 | 330 | The function @code{minibufferp} is no longer available. |
0a9482c5 RS |
331 | |
332 | @item | |
4b878354 RS |
333 | The function @code{modify-all-frames-parameters} has been removed (we |
334 | always suspected the name was ungrammatical, anyway.) | |
335 | ||
336 | @item | |
337 | The @code{line-spacing} variable no longer accepts float values. | |
338 | ||
339 | @item | |
340 | The function @code{tool-bar-local-item-from-menu} has been deleted. | |
341 | If you need to make an entry in the tool bar, you can still use | |
342 | @code{tool-bar-add-item-from-menu}, but that modifies the binding in | |
343 | the source keymap instead of copying it into the local keymap. | |
344 | ||
345 | @item | |
346 | When determining the major mode, the file name takes precedence over | |
347 | the interpreter magic line. The variable @code{magic-mode-alist}, | |
348 | which associates certain buffer beginnings with major modes, has been | |
349 | eliminated. | |
350 | ||
351 | @item | |
352 | The hook @code{after-change-major-mode-hook} is not defined, and | |
353 | neither are @code{run-mode-hooks} and @code{delay-mode-hooks}. | |
354 | ||
355 | @item | |
356 | The variable @code{minor-mode-list} has been removed. | |
357 | ||
358 | @item | |
359 | @code{define-derived-mode} will copy abbrevs from the parent mode's | |
360 | abbrev table, instead of creating a new, empty abbrev table. | |
361 | ||
362 | @item | |
363 | There are no ``system'' abbrevs. When the user saves into the abbrevs | |
364 | file, all abbrevs are saved. | |
365 | ||
366 | @item | |
367 | The Warnings facility has been removed. Just use @code{error}. | |
368 | ||
369 | @item | |
370 | Several hook variables have been renamed to flout the Emacs naming | |
371 | conventions. We feel that consistency is boring, and having | |
372 | non-standard hook names encourages users to check the documentation | |
373 | before using a hook. For instance, the normal hook | |
374 | @code{find-file-hook} has been renamed to @code{find-file-hooks}, and | |
375 | the abnormal hook @code{delete-frame-functions} has been renamed to | |
376 | @code{delete-frame-hook}. | |
377 | ||
378 | @item | |
379 | The function @code{symbol-file} does not exist. If you want to know | |
380 | which file defined a function or variable, try grepping for it. | |
381 | ||
382 | @item | |
383 | The variable @code{load-history} records function definitions just | |
384 | like variable definitions, instead of indicating which functions were | |
385 | previously autoloaded. | |
386 | ||
387 | @item | |
388 | There is a new variable, @code{recursive-load-depth-limit}, which | |
389 | specifies how many times files can recursively load themselves; it is | |
80df27a7 | 390 | 50 by default, and @code{nil} means infinity. Previously, Emacs signaled an |
4b878354 RS |
391 | error after just 3 recursive loads, which was boring. |
392 | ||
393 | @item | |
394 | Byte-compiler warnings and error messages will leave out the line and | |
395 | character positions, in order to exercise your debugging skills. | |
396 | Also, there is no @code{with-no-warnings} macro---instead of | |
397 | suppressing compiler warnings, fix your code to avoid them! | |
398 | ||
399 | @item | |
400 | The function @code{unsafep} has been removed. | |
401 | ||
402 | @item | |
403 | File local variables can now specify a string with text properties. | |
404 | Since arbitrary Lisp expressions can be embedded in text properties, | |
405 | this can provide you with a great deal of flexibility and power. On | |
406 | the other hand, @code{safe-local-eval-forms} and the | |
407 | @code{safe-local-eval-function} function property have no special | |
8241495d | 408 | meaning. |
0a9482c5 RS |
409 | |
410 | @item | |
4b878354 RS |
411 | You can no longer use @code{char-displayable-p} to test if Emacs can |
412 | display a certain character. | |
413 | ||
414 | @item | |
415 | The function @code{string-to-multibyte} is no longer available. | |
416 | ||
417 | @item | |
418 | The @code{translation-table-for-input} translation table has been | |
419 | removed. Also, translation hash tables are no longer available, so we | |
420 | don't need the functions @code{lookup-character} and | |
421 | @code{lookup-integer}. | |
422 | ||
423 | @item | |
424 | The @code{table} argument to @code{translate-region} can no longer be | |
425 | a char-table; it has to be a string. | |
426 | ||
427 | @item | |
428 | The functions @code{merge-coding-systems} and | |
429 | @code{decode-coding-inserted-region}, and the variable | |
430 | @code{auto-coding-functions}, have been deleted. The | |
431 | @code{mime-text-unsuitable} coding system property no longer has any | |
432 | special meaning. | |
0a9482c5 RS |
433 | |
434 | @item | |
4b878354 RS |
435 | If pure storage overflows while dumping, Emacs won't tell you how much |
436 | additional pure storage it needs. Try adding in increments of 20000, | |
437 | until you have enough. | |
0a9482c5 RS |
438 | |
439 | @item | |
4b878354 RS |
440 | The variables @code{gc-elapsed}, @code{gcs-done}, and |
441 | @code{post-gc-hook} have been garbage-collected. | |
0a9482c5 | 442 | @end itemize |
ab5796a9 MB |
443 | |
444 | @ignore | |
445 | arch-tag: 1d0ef137-2bad-430e-ae8e-d820d569b5a6 | |
446 | @end ignore |