6 This file presents some general information about XEmacs. It is
7 primarily about the changes in recent XEmacs versions and its release
10 Use `C-c C-f' to move to the next equal level of outline, and
11 `C-c C-b' to move to previous equal level. `C-h m' will give more
12 info about the Outline mode. Many commands are also available through
15 Users who would like to know which capabilities have been introduced
16 in each release should look at the appropriate section of this file.
17 Starting with version 20.0, XEmacs includes ChangeLogs, which can be
18 consulted for a more detailed list of changes.
20 Users interested in some of the details of how XEmacs differs from GNU
21 Emacs should read the section "What's Different?" near the end of this
24 N.B. The term "GNU Emacs" refers to any release of Emacs Version
25 19 from the Free Software Foundation's GNU Project. (We do not
26 say just "Emacs" as Richard M. Stallman ["RMS"] prefers, because
27 it is clearly a more generic term.) The term "XEmacs" refers to
28 this program or to its predecessors "Era" and "Lucid Emacs". The
29 predecessor of all these program is called "Emacs 18". When no
30 particular version is implied, "Emacs" will be used.
33 * Changes in XEmacs 21.2
34 ========================
36 ** `delete-key-deletes-forward' now defaults to t.
38 `delete-key-deletes-forward' is the variable that regulates the
39 behaviour of the delete key on the systems that offer both a backspace
40 and a delete key. If set to nil, the key labeled "Delete" will delete
41 backward. If set to non-nil, the "Delete" key will delete forward,
42 except on keyboards where a "Backspace" key is not provided.
44 Unless our implementation has bugs, the only reason why you would want
45 to set `delete-key-deletes-forward' to nil is if you want to use the
46 Delete key to delete backwards, despite the presence (according to
47 Xlib) of a BackSpace key on the keyboard.
49 ** Interactive searching and matching case improvements.
51 Case sensitiveness in searching operations is normally controlled by
52 the variable `case-fold-search' (if non-nil, case is ignored while
53 searching). This mechanism has now been slightly improved for
54 interactive searches: if the search string (or regexp) contains
55 uppercase characters, the searching is forced to be case-sensitive,
58 The new behavior affects all functions performing interactive
59 searches, like `zap-to-char', `list-matching-lines', `tags-search'
60 etc. The incremental search facility has always behaved that way.
62 ** The rectangle functions have been almost completely rewritten in
63 order to avoid inserting undesirable spaces, notably at the end of
64 lines. Two typical examples of the old behavior were
65 `string-rectangle', which filled all lines up to the right side of the
66 rectangle, and `clear-rectangle', which filled even empty lines up to
67 the left side. All functions have been rewritten to avoid inserting
68 unwanted spaces, and an optional prefix now allows them to behave the
71 As a side effect, the FORCE argument to `move-to-column' now
72 understands the special value `coerce', which means that the line
73 should not be filled if it is too short to reach the desired column.
75 ** Incremental search will now highlight all visible matches, making
76 it easier to anticipate where consecutive C-s or C-r will place the
77 point. If you want to disable the feature, set
78 `isearch-highlight-all-matches' to nil.
80 ** You can now customize and save comments for faces and variables.
81 In Custom buffers, a new menu entry allows you to add and edit a
82 comment. Comments for variables can also be assigned by calling
83 `customize-set-(value|variable)' with a prefix argument.
85 ** XEmacs now locates the early package hierarchies at
86 ~/.xemacs/mule-packages/ and ~/.xemacs/xemacs-packages/. Previously,
87 the early packages were located in ~/.xemacs/.
89 ** You can now create "indirect buffers", like in GNU Emacs. An
90 indirect buffer shares its text with another buffer ("base buffer"),
91 but has its own major mode, local variables, extents, and narrowing.
92 An indirect buffer has a name of its own, distinct from those of the
93 base buffer and all other buffers. An indirect buffer cannot itself
94 be visiting a file (though its base buffer can be). The base buffer
95 cannot itself be indirect.
97 Use (make-indirect-buffer BASE-BUFFER NAME) to make an indirect buffer
98 named NAME whose base is BASE-BUFFER. If BASE-BUFFER is itself an
99 indirect buffer, its base buffer is used as the base for the new
102 You can make an indirect buffer current, or switch to it in a window,
103 just as you would a non-indirect buffer.
105 The function `buffer-base-buffer' returns a buffer's base buffer or
106 nil, if given an ordinary (non-indirect) buffer. The function
107 `buffer-indirect-children' returns a list of the indirect children of
110 ** User names following the tilde character can now be completed at
111 file name prompts; e.g. `C-x C-f ~hni<TAB>' will complete to
112 `~hniksic/'. To make this operation faster, a cache of user names is
113 maintained internally.
115 The new primitives available for this purpose are functions named
116 `user-name-completion' and `user-name-all-completions'.
118 ** XEmacs can now play sound using Enlightenment Sound Daemon (ESD).
119 It will try NAS first, then ESD, then playing native sound directly.
121 ** X-Face support is now available under MS-Windows.
122 If an X-Face libary built under MS-Windows is available then XEmacs
123 will use this at build time.
125 ** The font-menu is now available under MS-Windows.
127 ** MS-Windows support for selection is now much more robust.
129 Generally selection should now do what you would expect under
130 MS-Windows: the middle mouse button will paste your current selection
131 or the clipboard; conversions from different types of selection to the
132 clipboard can be made; the kill-ring and friends will be updated as
135 The only thing selection doesn't do is set the clipboard automatically
136 as this would break the MS-Windows model. If you want this behaviour
137 then set `selection-sets-clipboard' to t
139 ** Mail spool locking now works correctly.
140 XEmacs has always come with a little auxiliary program, movemail,
141 which moves mail out of the system's spool area into user storage. To
142 coordinate between XEmacs, the mail delivery agent, and other mail
143 user agents, movemail needs to properly lock the spool file before
144 moving it. Movemail now correctly respects the --mail-locking option
145 to configure. Moreover, movemail's locking behavior can be specified
146 at run-time, via a new command-line option -m to movemail, or through
147 the environment variable EMACSLOCKMETHOD.
149 When installing XEmacs, make sure you configure it according to your
150 environment's mail spool locking conventions. When you're using a
151 binary kit, set the `mail-lock-method' variable at startup, or the
152 EMACSLOCKMETHOD environment variable.
154 ** New command-line switches -user-init-file and -user-init-directory.
155 These can be used to specify alternate locations for what is normally
156 ~/.emacs and ~/.xemacs.
158 Moreover, -user <user> (which used to only work in unpredictable ways)
160 -user-init-file ~<user>/.emacs -user-init-directory ~<user>/.xemacs.
162 ** New variable `mswindows-meta-activates-menu'.
163 If you set this variable to nil then pressing the Alt key under
164 MS-Windows will no longer activate the menubar. The default is t.
168 *** In DOS, etags looks for file.cgz if it cannot find file.c.
170 *** New option --ignore-case-regex is an alternative to --regex. It is now
171 possible to bind a regexp to a language, by prepending the regexp with
172 {lang}, where lang is one of the languages that `etags --help' prints out.
173 This feature is useful especially for regex files, where each line contains
174 a regular expression. The manual contains details.
176 *** In C and derived languages, etags creates tags for function
177 declarations when given the --declarations option.
179 *** In C++, tags are created for "operator". The tags have the form
180 "operator+", without spaces between the keyword and the operator.
182 *** New language Ada: tags are functions, procedures, packages, tasks, and
185 *** In Fortran, procedure is no more tagged.
187 *** In Java, tags are created for "interface".
189 *** In Lisp, "(defstruct (foo", "(defun (operator" and similar constructs
192 *** In Perl, the --globals option tags global variables. my and local
193 variables are tagged.
195 *** New language Python: def and class at the beginning of a line are tags.
197 *** .ss files are Scheme files, .pdb is Postscript with C syntax, .psw is
201 * Lisp and internal changes in XEmacs 21.2
202 ==========================================
204 ** A new portable dumper is available.
206 Olivier Galibert has written a portable dumper for XEmacs, based on
207 initial work by Kyle Jones. Normally, XEmacs C sources link into an
208 executable called `temacs', which loads the Lisp code and "unexecs"
209 into a proper `xemacs' executable. The unexec() process is hard to
210 implement correctly and makes XEmacs very hard to port to new
211 operating systems, or even to new releases of old systems.
213 A portable dumper is a different approach to dumping: instead of
214 dumping full-fledged executable, it only dumps out the initialized
215 data structures (both Lisp and C) into an external file. A normally
216 running XEmacs only needs to mmap() that file and relocate a bit to
217 get to the initialized data. In that scheme, there is no difference
218 between `temacs' and `xemacs'.
220 This is all very experimental, though. Configure with `--pdump' to
221 try testing it. NOTE: it is expected that `make' will fail after
222 dumping `xemacs.dmp'. This is because Makefiles have not yet been
223 modified to not expect `temacs' producing an `xemacs' executable. You
224 can try it out by simply running `src/temacs'. If it starts without
225 failure, the portable dumping worked.
227 ** Much effort has been invested to make XEmacs Lisp faster:
229 *** Many basic lisp operations are now faster.
230 This is especially the case when running a Mule-enabled XEmacs.
232 A general overhaul of the lisp engine should produce a speedup of 1.4
233 in a Latin-1 XEmacs, and 2.1 in a Mule XEmacs. These numbers were
234 obtained running `(byte-compile "simple.el")', which should be a
235 pretty typical test of "pure" Lisp.
237 *** Lisp hash tables have been re-implemented. The Common Lisp style
238 hash table interface has been made standard, and moved from cl.el into
239 fast C code (See the section on hash tables in the XEmacs Lisp
240 Reference). A speedup factor of 3 can be expected with code that
241 makes intensive use of hash tables.
243 *** The garbage collector has been tuned, leading to a speedup of
246 *** The family of functions that iterate over lists, like `memq', and
247 `rassq', have been made a little faster (typically 1.3).
249 *** Lisp function calls are faster, by approximately a factor of two.
250 However, defining inline functions (via defsubst) still makes sense
253 *** Finally, a few functions have had dramatic performance
254 improvements. For example, `(last long-list)' is now 30 times faster.
256 Of course, your mileage will vary.
258 Many operations do not see any improvement. Surprisingly, running
259 (font-lock-fontify-buffer) does not use the Lisp engine much at all.
260 Speeding up your favorite slow operation is an excellent project to
261 improve XEmacs. Don't forget to profile!
263 ** Native widgets can be displayed in buffers.
265 The glyph system has been extended to allow the display of glyphs that
266 are implemented as native window-system widgets. Thus you can embed
267 buttons, scrollbars, combo boxes, edit fields and progress gauges in a
268 buffer. As a side effect subwindow support now works once again.
270 All of this is still very experimental. This feature is currently
271 more complete under MS-Windows.
273 ** user-init-directory is now an absolute, unexpanded path.
274 Previously, `user-init-directory' used to be relative to
275 (concat "~" init-file-user). This turned out to be too complicated
276 for most packages (and some core Lisp files) to use correctly.
278 Also, `init-file-user' has been obsoleted in the process.
280 ** XEmacs finally has an automated test suite!
281 Although this is not yet very sophisticated, it is already responsible
282 for several important bug fixes in XEmacs. To try it out, simply use
283 the makefile target `make check' after building XEmacs.
285 ** Hash tables have been reimplemented.
286 As was pointed out above, the standard interface to hash tables is now
287 the Common Lisp interface, as described in Common Lisp, the Language
288 (CLtL2, by Steele). The older interface (functions with names
289 containing the phrase `hashtable') will continue to work, but the
290 preferred interface now has names containing the phrase `hash-table'.
292 Here's the executive overview: create hash tables using
293 make-hash-table, and use gethash, puthash, remhash, maphash and
294 clrhash to manipulate entries in the hash table. See the (updated)
295 Lisp Reference Manual for details.
297 ** Lisp code handles circular lists much more robustly.
298 Many basic lisp functions used to loop forever when given a circular
299 list, expecting you to C-g (quit) out of the loop. Now this is more
300 likely to trigger a `circular-list' error. Printing a circular list
301 now results in something like this:
303 (let ((x (cons 'foo 'foo)))
306 => (foo ... <circular list>)
308 An extra bonus is that checking for circularities is not just
309 friendlier, but actually faster than checking for C-g.
311 ** Functions for decoding base64 encoding are now available; see
312 `base64-encode-region', `base64-encode-string', `base64-decode-region'
313 and `base64-decode-string'.
315 ** The arguments to `locate-file' are now more Lisp-like. As before,
318 (locate-file FILENAME PATH-LIST &optional SUFFIXES MODE)
320 Except that SUFFIXES are now a list of strings instead of a single,
321 colon-separated string. MODE is now a symbol or a list of symbols
322 (symbols `exists', `executable', `writable', and `readable' are
323 supported) instead of an integer code. See the documentation for
324 details. Of course, the old form is still accepted for backward
327 Several bugs in locate-file have been fixed, most notably its failure
328 to call expand-file-name on elements of PATH-LIST. Because of that
329 elements of load-path of the form "~/..." used to not work.
330 locate-file is now guaranteed to expand files during its course of
333 ** `translate-region' has been improved in several ways. Its TABLE
334 argument used to be a 256-character string. In addition to this, it
335 can now also be a vector or a char-table, which makes the function
336 useful for Mule, which it wasn't. If TABLE a vector or a generic
337 char-table, you can map characters to strings instead of to other
338 characters. For instance:
340 (let ((table (make-char-table 'generic)))
341 (put-char-table ?a "the letter a" table)
342 (put-char-table ?b "" table)
343 (put-char-table ?c ?\n table)
344 (translate-region (point-min) (point-max) table))
346 ** The new form `ignore-file-errors', similar to `ignore-errors' may
347 be used as a short-hand for condition-case when you wish to ignore
348 file-related error. For example:
350 (ignore-file-errors (delete-file "foo"))
352 ** The first argument to `intern-soft' may now also be a symbol, like
353 with `unintern'. If given a symbol, `intern-soft' will look for that
354 exact symbol rather than for any string. This is useful when you want
355 to check whether a specific symbol is interned in an obarray, e.g.:
360 (intern-soft (make-symbol "foo"))
363 ** The `keywordp' function now returns non-nil only on symbols
364 interned in the global obarray. For example:
366 (keywordp (intern ":foo" [0]))
368 (keywordp (intern ":foo")) ; The same as (keywordp :foo)
371 This behaviour is compatible with other code which treats symbols
372 beginning with colon as keywords only if they are interned in the
373 global obarray. `keywordp' used to wrongly return t in both cases
377 * Changes in XEmacs 21.0
378 ========================
380 ** XEmacs has been unbundled into constituent installable packages.
381 See the Info documentation under "Packages" for more information.
382 See the file `etc/PACKAGES' in the distribution for a partial list of
383 packages available at the time of the 21.0 release.
385 ** XEmacs is now supported under Microsoft Windows 95/98 and Windows
386 NT operating systems. For starters, look at the XEmacs on Windows FAQ
387 at <URL:http://jagor.srce.hr/~hniksic/xemacs-on-windows-faq.txt>. To
388 discuss Windows-specific issues, subscribe to the mailing list at
389 <xemacs-nt-request@xemacs.org>.
391 ** XEmacs will now use `XEmacs' as its application class if it finds
392 any `XEmacs' resources in the resource database. Otherwise, it will
393 continue to use the `Emacs' class.
395 ** The options menu has been ported to Custom.
396 This means that each entry in the options menu acts as if you had customized
397 the corresponding variable by hand. ### WARNING: there is currently no
398 upgrading function to help you port your old options settings to the new
399 format. Consequently, if you want to modify the options for XEmacs 21, you
400 will have to set them all again through the menu, and remove the code loading
401 .xemacs-options from your .emacs.
403 ** When the Zmacs region is active, `M-x query-replace' and the other
404 replace commands now operate on the region contents only.
406 ** XEmacs now is able to choose X visuals and use private colormaps.
407 The '-visual <visualStr>' command line option or the '.EmacsVisual'
408 Xresource controls which visual XEmacs will use, and
409 '-privateColormap' or '.privateColormap' will force XEmacs to create a
410 private colormap for use. The syntax for the visual string is
411 "<visual><bitdepth>" where <visual> is one of 'StaticColor',
412 'TrueColor', 'GrayScale', 'PseudoColor' or 'DirectColor' and
413 <bitdepth> is the appropriate number of bits per pixel. If an invalid
414 or non-supported combination is entered, XEmacs attempts to find a happy
415 medium. The X creation mechanism will then determine if it needs to
416 create a colormap for use, or the presence of the private flags will
417 force it to create it.
419 ** The `imenu' package has been ported to XEmacs and is available as a
422 ** `echo-keystrokes' can now be a floating-point number, so that you
423 can set it to intervals shorter than one second.
425 (setq echo-keystrokes 0.1)
427 ** The new command `center-to-window-line' works like `recenter'
428 (bound to `C-l'), only it does not redisplay the whole display area.
430 ** The M-. command will now first search through exact tags matches,
431 and then through inexact matches, as one would expect.
433 ** The new variable `user-full-name' can be used to customize one's
434 name when using the Emacs mail and news reading facilities.
436 Normally, `user-full-name' is a function that returns the full name of
437 a user or UID, as specified by the system -- for instance,
438 (user-full-name "root") returns something like "Super-User". However,
439 when the function is called without arguments, it will return the
440 value of the `user-full-name' variable. The `user-full-name' variable
441 is initialized using the environment variable NAME and (failing that)
442 the user's system name.
444 The behavior of the `user-full-name' function with an argument
445 specified is unchanged.
447 ** The new command `M-x customize-changed-options' lets you customize
448 all the options whose default values have changed in recent Emacs
449 versions. You specify a previous Emacs version number as argument,
450 and the command creates a customization buffer showing all the
451 customizable options whose default values were changed since that
454 If you don't specify a particular version number argument, then the
455 customization buffer shows all the customizable options for which
456 Emacs versions of changes are recorded.
458 ** The new command `add-log-convert' can be used to convert the
459 old-style (pre-20.3) ChangeLog buffers to new style, for
460 consistency. A reminder: if you wish to revert to old-style
461 ChangeLogs instead, customize the value of `add-log-time-format'
464 ** The new command `zap-up-to-char' is now available. It is similar
465 to `zap-to-char', except that it does not delete the searched-for
466 character. It is not bound to a key by default.
468 ** You can now store a number into a register with `C-u NUMBER C-x r n'
469 REG, increment it by INC with `C-u INC C-x r + REG' (to increment by
470 one, omit C-u INC), and insert it in the buffer with `C-x r g REG'.
471 This is useful for writing keyboard macros.
473 ** The M-: command, when given a prefix argument, will now insert its
474 result to the current buffer.
476 ** The `C-h c' command, when given a prefix argument, will now insert
477 the message into the current buffer.
479 ** Horizontally split windows may now be dragged using the mouse.
480 Because of this, the dividers between vertical windows are always
481 visible. To turn it off, set `vertical-divider-always-visible-p' to
484 ** XEmacs/Mule (internationalization) changes.
486 *** Mule support now works on TTY's. Use `set-terminal-coding-system'
487 and `set-keyboard-coding-system' to specify the coding system of your
488 display and keyboard.
490 *** Egg/SJ3 input method is now officially supported. Quail and
491 Egg/Skk have been available through the generalized Leim since 20.3.
493 *** Localized Japanese menubars are available if XEmacs is built with
494 XFONTSET and either the X11 libraries are built with X_LOCALE defined
495 or the native C libraries support Japanese localization. This has
496 been available since 20.3, only it hasn't been announced before.
498 ** Jamie Zawinski's `gdb-highlight' extension is now distributed with
499 the `debug' package. gdb-highlight makes most objects printed in a
500 gdb buffer be mouse-sensitive: as text shows up in the buffer, it is
501 parsed, and objects which are recognized have context-sensitive
502 commands attached to them. To use it, add the following to `.emacs':
504 (add-hook 'gdb-mode-hook (lambda () (require 'gdb-highlight)))
506 ** The package popper.el is now included in the edit-utils package.
507 It has been greatly enhanced with respect to the one once included
508 with the ilisp package and should work well under XEmacs 21.0.
512 *** Like the old 'gnudoit' program. Gnuclient -batch now can read from stdin.
514 *** Gnuclient -batch no longer breaks off the output at the first LF.
518 *** Multiline macros are now handled, both as they affect indentation,
519 and as recognized syntax. New syntactic symbol cpp-macro-cont is
520 assigned to second and subsequent lines of a multiline macro
523 *** A new style "user" which captures all non-hook-ified
524 (i.e. top-level) .emacs file variable setings and customizations.
525 Style "cc-mode" is an alias for "user" and is deprecated. "gnu" style
526 is still the default however.
528 *** "java" style now conforms to Sun's JDK coding style.
530 *** There are new commands c-beginning-of-defun, c-end-of-defun which
531 are alternatives which you could bind to C-M-a and C-M-e if you prefer
532 them. They do not have key bindings by default.
534 *** New and improved implementations of M-a (c-beginning-of-statement)
535 and M-e (c-end-of-statement).
537 *** C++ namespace blocks are supported, with new syntactic symbols
538 namespace-open, namespace-close, and innamespace.
540 *** File local variable settings of c-file-style and c-file-offsets
541 makes the style variables local to that buffer only.
543 *** New indentation functions c-lineup-close-paren,
544 c-indent-one-line-block, c-lineup-dont-change.
546 *** Improvements (hopefully!) to the way CC Mode is loaded. You
547 should now be able to do a (require 'cc-mode) to get the entire
548 package loaded properly for customization in your .emacs file. A new
549 variable c-initialize-on-load controls this and is t by default.
551 ** In Text mode, now only blank lines separate paragraphs.
552 This makes it possible to get the full benefit of Adaptive Fill mode
553 in Text mode, and other modes derived from it (such as Mail mode).
554 TAB in Text mode now runs the command indent-relative; this makes a
555 practical difference only when you use indented paragraphs.
557 As a result, the old Indented Text mode is now identical to Text mode,
558 and is an alias for it.
560 If you want spaces at the beginning of a line to start a paragraph,
561 use the new mode, Paragraph Indent Text mode.
563 ** Changes to Gnus, the XEmacs newsreader.
565 *** New functionality for using Gnus as an offline newsreader has been
566 added. A plethora of new commands and modes have been added. See the
567 Gnus manual for the full story.
569 *** The nndraft backend has returned, but works differently than
570 before. All Message buffers are now also articles in the nndraft
571 group, which is created automatically.
573 *** `gnus-alter-header-function' can now be used to alter header
576 *** `gnus-summary-goto-article' now accept Message-ID's.
578 *** A new Message command for deleting text in the body of a message
579 outside the region: `C-c C-v'.
581 *** You can now post to component group in nnvirtual groups with
584 *** `nntp-rlogin-program' -- new variable to ease customization.
586 *** `C-u C-c C-c' in `gnus-article-edit-mode' will now inhibit
587 re-highlighting of the article buffer.
589 *** New element in `gnus-boring-article-headers' -- `long-to'.
591 *** `M-i' symbolic prefix command. See the section "Symbolic
592 Prefixes" in the Gnus manual for details.
594 *** `L' and `I' in the summary buffer now take the symbolic prefix
595 `a' to add the score rule to the "all.SCORE" file.
597 *** `gnus-simplify-subject-functions' variable to allow greater
598 control over simplification.
600 *** `A T' -- new command for fetching the current thread.
602 *** `/ T' -- new command for including the current thread in the
605 *** `M-RET' is a new Message command for breaking cited text.
607 *** \\1-expressions are now valid in `nnmail-split-methods'.
609 *** The `custom-face-lookup' function has been removed.
610 If you used this function in your initialization files, you must
611 rewrite them to use `face-spec-set' instead.
613 *** Cancelling now uses the current select method. Symbolic prefix
614 `a' forces normal posting method.
616 *** New command to translate M******** sm*rtq**t*s into proper text
619 *** For easier debugging of nntp, you can set `nntp-record-commands'
622 *** nntp now uses ~/.authinfo, a .netrc-like file, for controlling
623 where and how to send AUTHINFO to NNTP servers.
625 *** A command for editing group parameters from the summary buffer
628 *** A history of where mails have been split is available.
630 *** A new article date command has been added -- `article-date-iso8601'.
632 *** Subjects can be simplified when threading by setting
633 `gnus-score-thread-simplify'.
635 *** A new function for citing in Message has been added --
636 `message-cite-original-without-signature'.
638 *** `article-strip-all-blank-lines' -- new article command.
640 *** A new Message command to kill to the end of the article has
643 *** A minimum adaptive score can be specified by using the
644 `gnus-adaptive-word-minimum' variable.
646 *** The "lapsed date" article header can be kept continually
647 updated by the `gnus-start-date-timer' command.
649 *** Web listserv archives can be read with the nnlistserv backend.
651 *** Old dejanews archives can now be read by nnweb.
653 *** Byte-compilation of user-specs now works under XEmacs.
655 ** The `dir' files are no longer essential for functioning of the Info
656 subsystem. If the `dir' file does not exist in an Info directory, the
657 relevant information will be generated on-the-fly.
659 This behavior can be customized, look for `Info-auto-generate-directory'
660 and `Info-save-auto-generated-dir' in the `info' customization group.
663 * Lisp and internal changes in XEmacs 21.0
664 ==========================================
666 ** It is now possible to build XEmacs with support for 31-bit Lisp
667 integers (normally, Lisp integers are only 28 bits wide on 32-bit
668 machines.) Configure with --use-minimal-tagbits to test. With this
669 change, the maximum buffer size on 32-bit machines is increased from
670 128M to 1G. This setting will be made default in a future XEmacs
673 ** Specifier changes.
675 *** When instantiating a specifier, the window locale now has a higher
676 precedence than the buffer locale. This is because the window locale
677 is more specific than the buffer locale.
679 *** The new macro `let-specifier' can be used to temporarily add
680 specifications to specifiers. See the documentation for details.
682 *** The new specifiers `vertical-scrollbar-visible-p' and
683 `horizontal-scrollbar-visible-p' may be used to control scrollbar
684 visibility. Previously, the only way to remove a scrollbar was to set
685 its size to 0. This method is still supported for backward
688 *** The new specifiers `scrollbar-on-left-p' and `scrollbar-on-top-p'
689 may be used to control the position of the vertical and horizontal
690 toolbar. Previously, their position could be changed only through the
693 *** The new draggable vertical dividers between windows may be turned
694 off using the `vertical-divider-always-visible-p' specifier. When
695 this is set to nil, the vertical dividers between windows are shown
696 only when needed, and they are not draggable.
698 Other properties of the vertical dividers may be controlled using
699 `vertical-divider-shadow-thickness', `vertical-divider-line-width' and
700 `vertical-divider-spacing' specifiers, which see.
702 ** Frame focus management changes.
704 *** When the variable focus-follows-mouse is non-nil, `select-frame'
705 no longer permanently selects a different frame. The frame selection
706 is temporary and is reverted when the current command terminates, much
707 like the buffer selected by `set-buffer'. This is the same as in FSF
710 *** The new function `focus-frame' sets the window system focus to
711 FRAME (and selects it), regardless of the value of
712 `focus-follows-mouse'. Doing this is not well behaved, so be
713 absolutely sure that you want this.
715 The code that uses `select-frame' only to get the window manager focus
716 should be changed to use `set-frame-focus' instead, so that they keep
717 working when `focus-follows-mouse' is non-nil.
719 *** The special forms `save-selected-frame' and `with-selected-frame'
720 can now be used to temporarily change selected frame.
722 *** The behavior of `other-frame' command (`C-x 5 o') is unaffected by
725 ** The function `select-window' now has an optional second argument
726 NORECORD which if non-nil inhibits the recording of a buffer change.
728 ** The function `vertical-motion' now correctly handles the second,
729 optional WINDOW argument. A new third argument PIXELS, if non-nil,
730 indicates that the returned motion should be in pixels.
732 ** The new function `vertical-motion-pixels' is similar to
733 vertical-motion but takes as input a vertical motion in pixels.
735 ** The new functions window-text-area-pixel-{width,height,edges} can
736 be used to obtain information about the text-displaying area of a
739 ** The new functions `shrink-window-pixels' and `enlarge-window-pixels'
740 can be used to adjust the size of a window by a pixel amount.
742 ** The new function `window-displayed-text-pixel-height' can be used
743 to determine the height of the text actually displayed in a window.
745 ** The arithmetic comparison functions <, >, =, /= now accept a
746 variable number of arguments.
748 This means that if you want to test whether A < B < C, you can write
749 it as (< A B C) instead of (and (< A B) (< B C)). Likewise,
750 (apply #'> LIST) now tests if LIST is monotonously increasing -- and
753 ** The XEmacs hashtables now have a consistent read/print syntax.
754 This means that a hashtable will be readably printed in a
757 #s(hashtable size 2 data (key1 value1 key2 value2))
759 When XEmacs reads this form, it will create a new hashtable according
760 to description. This allows you to easily dump hashtables to files
761 using `prin1', and read them back in using `read'.
763 If `print-readably' is non-nil, a more relaxed syntax is used; for
766 #<hashtable size 2/13 data (key1 value1 key2 value2) 0x874d>
768 ** It is now possible to build XEmacs with LDAP support.
769 You will need to install a LDAP library first. The following have
771 - LDAP 3.3 from the University of Michigan
772 (get it from <URL:http://www.umich.edu/~dirsvcs/ldap/>)
773 - OpenLDAP 1.0.3 from the OpenLDAP Foundation
774 (get it from <URL:http://www.openldap.org/>)
775 - LDAP SDK 1.0 from Netscape Corp.
776 (get it from <URL:http://developer.netscape.com/>)
778 ** When profiling is in effect, a call-count of all recorded functions
779 is now calculated. This information is stored in
780 `call-count-profile-table', and is utilized by `profile-results' as
781 well as the new command `profile-call-count-results'.
783 ** It is now an error to change the value of a symbol whose name
784 starts with a colon, if it is interned in the standard obarray.
786 However, setting such a symbol to its proper value, which is that
787 symbol itself, is not an error. This is for the sake of programs that
788 support pre-19.12 XEmacs and pre-20 GNU Emacs by explicitly setting
789 these variables to themselves.
791 ** The `concat' function no longer accepts integer arguments.
793 ** The new function `string' concatenates all its argument characters
794 and returns the resulting string. This is consistent with other
795 functions, like `list', `vector', etc.
797 ** The function `temp-directory' is now available to return the
798 directory to store temporary files. On Unix this will be obtained
799 from TMPDIR, defaulting to `/tmp'.
801 ** The function load-average now accepts an optional argument
802 USE-FLOATS. If it is non-nil, the load average values are returned as
803 floating point numbers, rather than as integers to be divided by 100.
805 ** The `make-event' function now supports the TYPE and PLIST
806 arguments, which can be used to create various events from Lisp. See
807 the documentation for details.
809 ** `function-interactive' is a new function that returns the
810 interactive specification of a funcallable object.
812 ** The new `lmessage' function allows printing of a formatted message
813 with a particular label.
815 (lmessage 'progress "Processing... %d" counter)
817 This function is more convenient than `display-message' because it
818 automatically applies `format' to its arguments.
820 ** The new `lwarn' function, analogous to `lmessage', allows printing
821 a formatted warning, with a non-default CLASS or LABEL.
823 ** The new function `split-path' can now be used to explode the
824 components of a colon-separated search path into a list.
826 (split-path "foo:bar")
829 ** Specifiers and symbols whose value is a specifier are now allowed
830 as modeline specifications.
832 ** defcustom now accepts the keyword `:version'. Use this to specify
833 in which version of Emacs a certain variable's default value changed.
836 (defcustom foo-max 34 "*Maximum number of foo's allowed."
841 This information is used to control the customize-changed-options
844 ** The line number tracking in modeline is now efficient, even for
845 very large buffers. This is achieved by caching the line numbers of
846 recent buffer positions, and reusing them. This cache is used only in
847 the buffers where `line-number-mode' is in effect.
849 ** When the new GNU Malloc aka Doug Lea Malloc is available, it will
850 be used. This should result in better performance on Linux systems
853 ** The code XEmacs uses to assemble its various paths into the
854 directory hierarchy has been rewritten to support the package system.
855 Look under "Startup Paths" in the Info documentation for more
858 *** site-lisp is no longer part of the load-path by default.
859 Its use is deprecated, but you can specify --with-site-lisp=yes at the
860 configure command line to get it back.
862 *** `Info-default-directory-list' is now obsolete. If you want to
863 change the path which XEmacs uses to search for info files, set
864 `Info-directory-list' instead.