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1
2 @iftex
3 @chapter Miscellaneous Commands
4
5 This chapter contains several brief topics that do not fit anywhere else.
6
7 @end iftex
8
9 @node Sorting, Shell, Calendar/Diary, Top
10 @section Sorting Text
11 @cindex sorting
12
13 XEmacs provides several commands for sorting text in a buffer. All
14 operate on the contents of the region (the text between point and the
15 mark). They divide the text of the region into many @dfn{sort records},
16 identify a @dfn{sort key} for each record, and then reorder the records
17 using the order determined by the sort keys. The records are ordered so
18 that their keys are in alphabetical order, or, for numerical sorting, in
19 numerical order. In alphabetical sorting, all upper-case letters `A'
20 through `Z' come before lower-case `a', in accordance with the ASCII
21 character sequence.
22
23 The sort commands differ in how they divide the text into sort
24 records and in which part of each record they use as the sort key. Most of
25 the commands make each line a separate sort record, but some commands use
26 paragraphs or pages as sort records. Most of the sort commands use each
27 entire sort record as its own sort key, but some use only a portion of the
28 record as the sort key.
29
30 @findex sort-lines
31 @findex sort-paragraphs
32 @findex sort-pages
33 @findex sort-fields
34 @findex sort-numeric-fields
35 @table @kbd
36 @item M-x sort-lines
37 Divide the region into lines and sort by comparing the entire
38 text of a line. A prefix argument means sort in descending order.
39
40 @item M-x sort-paragraphs
41 Divide the region into paragraphs and sort by comparing the entire
42 text of a paragraph (except for leading blank lines). A prefix
43 argument means sort in descending order.
44
45 @item M-x sort-pages
46 Divide the region into pages and sort by comparing the entire
47 text of a page (except for leading blank lines). A prefix
48 argument means sort in descending order.
49
50 @item M-x sort-fields
51 Divide the region into lines and sort by comparing the contents of
52 one field in each line. Fields are defined as separated by
53 whitespace, so the first run of consecutive non-whitespace characters
54 in a line constitutes field 1, the second such run constitutes field
55 2, etc.
56
57 You specify which field to sort by with a numeric argument: 1 to sort
58 by field 1, etc. A negative argument means sort in descending
59 order. Thus, minus 2 means sort by field 2 in reverse-alphabetical
60 order.
61
62 @item M-x sort-numeric-fields
63 Like @kbd{M-x sort-fields}, except the specified field is converted
64 to a number for each line and the numbers are compared. @samp{10}
65 comes before @samp{2} when considered as text, but after it when
66 considered as a number.
67
68 @item M-x sort-columns
69 Like @kbd{M-x sort-fields}, except that the text within each line
70 used for comparison comes from a fixed range of columns. An explanation
71 is given below.
72 @end table
73
74 For example, if the buffer contains:
75
76 @smallexample
77 On systems where clash detection (locking of files being edited) is
78 implemented, XEmacs also checks the first time you modify a buffer
79 whether the file has changed on disk since it was last visited or
80 saved. If it has, you are asked to confirm that you want to change
81 the buffer.
82 @end smallexample
83
84 @noindent
85 then if you apply @kbd{M-x sort-lines} to the entire buffer you get:
86
87 @smallexample
88 On systems where clash detection (locking of files being edited) is
89 implemented, XEmacs also checks the first time you modify a buffer
90 saved. If it has, you are asked to confirm that you want to change
91 the buffer.
92 whether the file has changed on disk since it was last visited or
93 @end smallexample
94
95 @noindent
96 where the upper case `O' comes before all lower case letters. If you apply
97 instead @kbd{C-u 2 M-x sort-fields} you get:
98
99 @smallexample
100 saved. If it has, you are asked to confirm that you want to change
101 implemented, XEmacs also checks the first time you modify a buffer
102 the buffer.
103 On systems where clash detection (locking of files being edited) is
104 whether the file has changed on disk since it was last visited or
105 @end smallexample
106
107 @noindent
108 where the sort keys were @samp{If}, @samp{XEmacs}, @samp{buffer},
109 @samp{systems}, and @samp{the}.@refill
110
111 @findex sort-columns
112 @kbd{M-x sort-columns} requires more explanation. You specify the
113 columns by putting point at one of the columns and the mark at the other
114 column. Because this means you cannot put point or the mark at the
115 beginning of the first line to sort, this command uses an unusual
116 definition of `region': all of the line point is in is considered part of
117 the region, and so is all of the line the mark is in.
118
119 For example, to sort a table by information found in columns 10 to 15,
120 you could put the mark on column 10 in the first line of the table, and
121 point on column 15 in the last line of the table, and then use this command.
122 Or you could put the mark on column 15 in the first line and point on
123 column 10 in the last line.
124
125 This can be thought of as sorting the rectangle specified by point and
126 the mark, except that the text on each line to the left or right of the
127 rectangle moves along with the text inside the rectangle.
128 @xref{Rectangles}.
129
130 @node Shell, Narrowing, Sorting, Top
131 @section Running Shell Commands from XEmacs
132 @cindex subshell
133 @cindex shell commands
134
135 XEmacs has commands for passing single command lines to inferior shell
136 processes; it can also run a shell interactively with input and output to
137 an XEmacs buffer @samp{*shell*}.
138
139 @table @kbd
140 @item M-!
141 Run a specified shell command line and display the output
142 (@code{shell-command}).
143 @item M-|
144 Run a specified shell command line with region contents as input;
145 optionally replace the region with the output
146 (@code{shell-command-on-region}).
147 @item M-x shell
148 Run a subshell with input and output through an XEmacs buffer.
149 You can then give commands interactively.
150 @item M-x term
151 Run a subshell with input and output through an XEmacs buffer.
152 You can then give commands interactively.
153 Full terminal emulation is available.
154 @end table
155
156 @menu
157 * Single Shell:: How to run one shell command and return.
158 * Interactive Shell:: Permanent shell taking input via XEmacs.
159 * Shell Mode:: Special XEmacs commands used with permanent shell.
160 * Terminal emulator:: An XEmacs window as a terminal emulator.
161 * Term Mode:: Special XEmacs commands used in Term mode.
162 * Paging in Term:: Paging in the terminal emulator.
163 @end menu
164
165 @node Single Shell, Interactive Shell, Shell, Shell
166 @subsection Single Shell Commands
167
168 @kindex M-!
169 @findex shell-command
170 @kbd{M-!} (@code{shell-command}) reads a line of text using the
171 minibuffer and creates an inferior shell to execute the line as a command.
172 Standard input from the command comes from the null device. If the shell
173 command produces any output, the output goes to an XEmacs buffer named
174 @samp{*Shell Command Output*}, which is displayed in another window but not
175 selected. A numeric argument, as in @kbd{M-1 M-!}, directs this command to
176 insert any output into the current buffer. In that case, point is left
177 before the output and the mark is set after the output.
178
179 @kindex M-|
180 @findex shell-command-on-region
181 @kbd{M-|} (@code{shell-command-on-region}) is like @kbd{M-!} but passes
182 the contents of the region as input to the shell command, instead of no
183 input. If a numeric argument is used to direct output to the current
184 buffer, then the old region is deleted first and the output replaces it as
185 the contents of the region.@refill
186
187 @vindex shell-file-name
188 @cindex environment
189 Both @kbd{M-!} and @kbd{M-|} use @code{shell-file-name} to specify the
190 shell to use. This variable is initialized based on your @code{SHELL}
191 environment variable when you start XEmacs. If the file name does not
192 specify a directory, the directories in the list @code{exec-path} are
193 searched; this list is initialized based on the @code{PATH} environment
194 variable when you start XEmacs. You can override either or both of these
195 default initializations in your @file{.emacs} file.@refill
196
197 When you use @kbd{M-!} and @kbd{M-|}, XEmacs has to wait until the
198 shell command completes. You can quit with @kbd{C-g}; that terminates
199 the shell command.
200
201 @node Interactive Shell, Shell Mode, Single Shell, Shell
202 @subsection Interactive Inferior Shell
203
204 @findex shell
205 To run a subshell interactively with its typescript in an XEmacs
206 buffer, use @kbd{M-x shell}. This creates (or reuses) a buffer named
207 @samp{*shell*} and runs a subshell with input coming from and output going
208 to that buffer. That is to say, any ``terminal output'' from the subshell
209 will go into the buffer, advancing point, and any ``terminal input'' for
210 the subshell comes from text in the buffer. To give input to the subshell,
211 go to the end of the buffer and type the input, terminated by @key{RET}.
212
213 XEmacs does not wait for the subshell to do anything. You can switch
214 windows or buffers and edit them while the shell is waiting, or while it is
215 running a command. Output from the subshell waits until XEmacs has time to
216 process it; this happens whenever XEmacs is waiting for keyboard input or
217 for time to elapse.
218
219 To get multiple subshells, change the name of buffer
220 @samp{*shell*} to something different by using @kbd{M-x rename-buffer}. The
221 next use of @kbd{M-x shell} creates a new buffer @samp{*shell*} with
222 its own subshell. By renaming this buffer as well you can create a third
223 one, and so on. All the subshells run independently and in parallel.
224
225 @vindex explicit-shell-file-name
226 The file name used to load the subshell is the value of the variable
227 @code{explicit-shell-file-name}, if that is non-@code{nil}. Otherwise, the
228 environment variable @code{ESHELL} is used, or the environment variable
229 @code{SHELL} if there is no @code{ESHELL}. If the file name specified
230 is relative, the directories in the list @code{exec-path} are searched
231 (@pxref{Single Shell,Single Shell Commands}).@refill
232
233 As soon as the subshell is started, it is sent as input the contents of
234 the file @file{~/.emacs_@var{shellname}}, if that file exists, where
235 @var{shellname} is the name of the file that the shell was loaded from.
236 For example, if you use @code{csh}, the file sent to it is
237 @file{~/.emacs_csh}.@refill
238
239 @vindex shell-pushd-regexp
240 @vindex shell-popd-regexp
241 @vindex shell-cd-regexp
242 @code{cd}, @code{pushd}, and @code{popd} commands given to the inferior
243 shell are watched by XEmacs so it can keep the @samp{*shell*} buffer's
244 default directory the same as the shell's working directory. These
245 commands are recognized syntactically by examining lines of input that are
246 sent. If you use aliases for these commands, you can tell XEmacs to
247 recognize them also. For example, if the value of the variable
248 @code{shell-pushd-regexp} matches the beginning of a shell command line,
249 that line is regarded as a @code{pushd} command. Change this variable when
250 you add aliases for @samp{pushd}. Likewise, @code{shell-popd-regexp} and
251 @code{shell-cd-regexp} are used to recognize commands with the meaning of
252 @samp{popd} and @samp{cd}.@refill
253
254 @kbd{M-x shell-resync-dirs} queries the shell and resynchronizes XEmacs'
255 idea of what the current directory stack is. @kbd{M-x
256 shell-dirtrack-toggle} turns directory tracking on and off.
257
258 @vindex input-ring-size
259 XEmacs keeps a history of the most recent commands you have typed in the
260 @samp{*shell*} buffer. If you are at the beginning of a shell command
261 line and type @key{M-p}, the previous shell input is inserted into the
262 buffer before point. Immediately typing @key{M-p} again deletes that
263 input and inserts the one before it. By repeating @key{M-p} you can
264 move backward through your commands until you find one you want to
265 repeat. You may then edit the command before typing @key{RET} if you
266 wish. @key{M-n} moves forward through the command history, in case you
267 moved backward past the one you wanted while using @key{M-p}. If you
268 type the first few characters of a previous command and then type
269 @key{M-p}, the most recent shell input starting with those characters is
270 inserted. This can be very convenient when you are repeating a sequence
271 of shell commands. The variable @code{input-ring-size} controls how
272 many commands are saved in your input history. The default is 30.
273
274
275 @node Shell Mode, Terminal emulator, Interactive Shell, Shell
276 @subsection Shell Mode
277
278 @cindex Shell mode
279 The shell buffer uses Shell mode, which defines several special keys
280 attached to the @kbd{C-c} prefix. They are chosen to resemble the usual
281 editing and job control characters present in shells that are not under
282 XEmacs, except that you must type @kbd{C-c} first. Here is a list
283 of the special key bindings of Shell mode:
284
285 @kindex RET (Shell mode)
286 @kindex C-c C-d (Shell mode)
287 @kindex C-d (Shell mode)
288 @kindex C-c C-u (Shell mode)
289 @kindex C-c C-w (Shell mode)
290 @kindex C-c C-c (Shell mode)
291 @kindex C-c C-z (Shell mode)
292 @kindex C-c C-\ (Shell mode)
293 @kindex C-c C-o (Shell mode)
294 @kindex C-c C-r (Shell mode)
295 @kindex C-c C-y (Shell mode)
296 @kindex M-p (Shell mode)
297 @kindex M-n (Shell mode)
298 @kindex TAB (Shell mode)
299 @findex send-shell-input
300 @findex shell-send-eof
301 @findex comint-delchar-or-maybe-eof
302 @findex interrupt-shell-subjob
303 @findex stop-shell-subjob
304 @findex quit-shell-subjob
305 @findex kill-output-from-shell
306 @findex show-output-from-shell
307 @findex copy-last-shell-input
308 @findex comint-previous-input
309 @findex comint-next-input
310 @findex comint-dynamic-complete
311 @vindex shell-prompt-pattern
312 @table @kbd
313 @item @key{RET}
314 At end of buffer send line as input; otherwise, copy current line to end of
315 buffer and send it (@code{send-shell-input}). When a line is copied, any
316 text at the beginning of the line that matches the variable
317 @code{shell-prompt-pattern} is left out; this variable's value should be a
318 regexp string that matches the prompts that you use in your subshell.
319 @item C-c C-d
320 Send end-of-file as input, probably causing the shell or its current
321 subjob to finish (@code{shell-send-eof}).
322 @item C-d
323 If point is not at the end of the buffer, delete the next character just
324 like most other modes. If point is at the end of the buffer, send
325 end-of-file as input, instead of generating an error as in other modes
326 (@code{comint-delchar-or-maybe-eof}).
327 @item C-c C-u
328 Kill all text that has yet to be sent as input (@code{kill-shell-input}).
329 @item C-c C-w
330 Kill a word before point (@code{backward-kill-word}).
331 @item C-c C-c
332 Interrupt the shell or its current subjob if any
333 (@code{interrupt-shell-subjob}).
334 @item C-c C-z
335 Stop the shell or its current subjob if any (@code{stop-shell-subjob}).
336 @item C-c C-\
337 Send quit signal to the shell or its current subjob if any
338 (@code{quit-shell-subjob}).
339 @item C-c C-o
340 Delete last batch of output from shell (@code{kill-output-from-shell}).
341 @item C-c C-r
342 Scroll top of last batch of output to top of window
343 (@code{show-output-from-shell}).
344 @item C-c C-y
345 Copy the previous bunch of shell input and insert it into the
346 buffer before point (@code{copy-last-shell-input}). No final newline
347 is inserted, and the input copied is not resubmitted until you type
348 @key{RET}.
349 @item M-p
350 Move backward through the input history. Search for a matching command
351 if you have typed the beginning of a command (@code{comint-previous-input}).
352 @item M-n
353 Move forward through the input history. Useful when you are
354 using @key{M-p} quickly and go past the desired command
355 (@code{comint-next-input}).
356 @item @key{TAB}
357 Complete the file name preceding point (@code{comint-dynamic-complete}).
358 @end table
359
360 @node Terminal emulator, Term Mode, Shell Mode, Shell
361 @subsection Interactive Inferior Shell with Terminal Emulator
362 @findex term
363
364 To run a subshell in a terminal emulator, putting its typescript in an XEmacs
365 buffer, use @kbd{M-x term}. This creates (or reuses) a buffer named
366 @samp{*term*} and runs a subshell with input coming from your keyboard and
367 output going to that buffer.
368
369 All the normal keys that you type are sent without any interpretation
370 by XEmacs directly to the subshell, as ``terminal input.''
371 Any ``echo'' of your input is the responsibility of the subshell.
372 (The exception is the terminal escape character,
373 which by default is @kbd{C-c}. @pxref{Term Mode}.)
374 Any ``terminal output'' from the subshell goes into the buffer,
375 advancing point.
376
377 Some programs (such as XEmacs itself) need to control the
378 appearance on the terminal screen in detail. They do this by
379 sending special control codes. The exact control
380 codes needed vary from terminal to terminal, but nowadays
381 most terminals and terminal emulators (including xterm)
382 understand the so-called "ANSI escape sequences" (first
383 popularized by the Digital's VT100 family of terminal).
384 The term mode also understands these escape sequences,
385 and for each control code does the appropriate thing
386 to change the buffer so that the appearance of the window
387 will match what it would be on a real terminal.
388 Thus you can actually run XEmacs inside an XEmacs Term window!
389
390 XEmacs does not wait for the subshell to do anything. You can switch
391 windows or buffers and edit them while the shell is waiting, or while
392 it is running a command. Output from the subshell waits until XEmacs
393 has time to process it; this happens whenever XEmacs is waiting for
394 keyboard input or for time to elapse.
395
396 To make multiple terminal emulators, rename the buffer @samp{*term*}
397 to something different using @kbd{M-x rename-uniquely},
398 just as with Shell mode.
399
400 The file name used to load the subshell is determined
401 the same way as for Shell mode.
402
403 Unlike Shell mode, Term mode does not track the current directory
404 by examining your input. Instead, if you use a programmable
405 shell, you can have it tell Term what the current directory is.
406 This is done automatically by bash for version 1.15 and later.
407
408 @node Term Mode, Paging in Term, Terminal emulator, Shell
409 @subsection Term Mode
410 @cindex Term mode
411 @cindex mode, Term
412
413 Term uses Term mode, which has two input modes:
414 In line mode, Term basically acts like Shell mode. @xref{Shell Mode}.
415 In Char mode, each character is sent directly to the inferior subshell,
416 except for the Term escape character, normally @kbd{C-c}.
417
418 To switch between line and char mode, use these commands:
419 @table @kbd
420 @kindex C-c C-k @r{(Term mode)}
421 findex term-char-mode
422 @item C-c C-k
423 Switch to line mode. Do nothing if already in line mode.
424
425 @kindex C-c C-j @r{(Term mode)}
426 @findex term-line-mode
427 @item C-c C-j
428 Switch to char mode. Do nothing if already in char mode.
429 @end table
430
431 The following commands are only available in Char mode:
432 @table @kbd
433 @item C-c C-c
434 Send a literal @key{C-c} to the sub-shell.
435
436 @item C-c C-x
437 A prefix command to conveniently access the global @key{C-x} commands.
438 For example, @kbd{C-c C-x o} invokes the global binding of
439 @kbd{C-x o}, which is normally @samp{other-window}.
440 @end table
441
442 @node Paging in Term,, Term Mode, Shell
443 @subsection Paging in the terminal emulator
444
445 Term mode has a pager feature. When the pager is enabled,
446 term mode will pause at the end of each screenful.
447
448 @table @kbd
449 @kindex C-c C-q @r{(Term mode)}
450 @findex term-pager-toggle
451 @item C-c C-q
452 Toggles the pager feature: Disables the pager if it is enabled,
453 and vice versa. This works in both line and char modes.
454 If the pager enabled, the mode-line contains the word @samp{page}.
455 @end table
456
457 If the pager is enabled, and Term receives more than a screenful
458 of output since your last input, Term will enter More break mode.
459 This is indicated by @samp{**MORE**} in the mode-line.
460 Type a @kbd{Space} to display the next screenful of output.
461 Type @kbd{?} to see your other options. The interface is similar
462 to the Unix @samp{more} program.
463
464 @node Narrowing, Hardcopy, Shell, Top
465 @section Narrowing
466 @cindex widening
467 @cindex restriction
468 @cindex narrowing
469
470 @dfn{Narrowing} means focusing in on some portion of the buffer, making
471 the rest temporarily invisible and inaccessible. Cancelling the narrowing
472 and making the entire buffer once again visible is called @dfn{widening}.
473 The amount of narrowing in effect in a buffer at any time is called the
474 buffer's @dfn{restriction}.
475
476 @c WideCommands
477 @table @kbd
478 @item C-x n n
479 Narrow down to between point and mark (@code{narrow-to-region}).
480 @item C-x n w
481 Widen to make the entire buffer visible again (@code{widen}).
482 @end table
483
484 Narrowing sometimes makes it easier to concentrate on a single
485 subroutine or paragraph by eliminating clutter. It can also be used to
486 restrict the range of operation of a replace command or repeating
487 keyboard macro. The word @samp{Narrow} appears in the mode line
488 whenever narrowing is in effect. When you have narrowed to a part of the
489 buffer, that part appears to be all there is. You can't see the rest,
490 can't move into it (motion commands won't go outside the visible part),
491 and can't change it in any way. However, the invisible text is not
492 gone; if you save the file, it will be saved.
493
494 @kindex C-x n n
495 @findex narrow-to-region
496 The primary narrowing command is @kbd{C-x n n} (@code{narrow-to-region}).
497 It sets the current buffer's restrictions so that the text in the current
498 region remains visible but all text before the region or after the region
499 is invisible. Point and mark do not change.
500
501 Because narrowing can easily confuse users who do not understand it,
502 @code{narrow-to-region} is normally a disabled command. Attempting to use
503 this command asks for confirmation and gives you the option of enabling it;
504 once you enable the command, confirmation will no longer be required. @xref{Disabling}.
505
506 @kindex C-x n w
507 @findex widen
508 To undo narrowing, use @kbd{C-x n w} (@code{widen}). This makes all
509 text in the buffer accessible again.
510
511 Use the @kbd{C-x =} command to get information on what part of the
512 buffer you narrowed down. @xref{Position Info}.
513
514 @node Hardcopy, Recursive Edit, Narrowing, Top
515 @section Hardcopy Output
516 @cindex hardcopy
517
518 The XEmacs commands for making hardcopy derive their names from the
519 Unix commands @samp{print} and @samp{lpr}.
520
521 @table @kbd
522 @item M-x print-buffer
523 Print hardcopy of current buffer using Unix command @samp{print}
524 @*(@samp{lpr -p}). This command adds page headings containing the file name
525 and page number.
526 @item M-x lpr-buffer
527 Print hardcopy of current buffer using Unix command @samp{lpr}.
528 This command does not add page headings.
529 @item M-x print-region
530 Like @code{print-buffer}, but prints only the current region.
531 @item M-x lpr-region
532 Like @code{lpr-buffer}, but prints only the current region.
533 @end table
534
535 @findex print-buffer
536 @findex print-region
537 @findex lpr-buffer
538 @findex lpr-region
539 @vindex lpr-switches
540 All the hardcopy commands pass extra switches to the @code{lpr} program
541 based on the value of the variable @code{lpr-switches}. Its value should
542 be a list of strings, each string a switch starting with @samp{-}. For
543 example, the value could be @code{("-Pfoo")} to print on printer
544 @samp{foo}.
545
546 @node Recursive Edit, Dissociated Press, Hardcopy, Top
547 @section Recursive Editing Levels
548 @cindex recursive editing level
549 @cindex editing level, recursive
550
551 A @dfn{recursive edit} is a situation in which you are using XEmacs
552 commands to perform arbitrary editing while in the middle of another
553 XEmacs command. For example, when you type @kbd{C-r} inside a
554 @code{query-replace}, you enter a recursive edit in which you can change
555 the current buffer. When you exit from the recursive edit, you go back to
556 the @code{query-replace}.
557
558 @kindex C-M-c
559 @findex exit-recursive-edit
560 @cindex exiting
561 @dfn{Exiting} a recursive edit means returning to the unfinished
562 command, which continues execution. For example, exiting the recursive
563 edit requested by @kbd{C-r} in @code{query-replace} causes query replacing
564 to resume. Exiting is done with @kbd{C-M-c} (@code{exit-recursive-edit}).
565
566 @kindex C-]
567 @findex abort-recursive-edit
568 You can also @dfn{abort} a recursive edit. This is like exiting, but
569 also quits the unfinished command immediately. Use the command @kbd{C-]}
570 (@code{abort-recursive-edit}) for this. @xref{Quitting}.
571
572 The mode line shows you when you are in a recursive edit by displaying
573 square brackets around the parentheses that always surround the major
574 and minor mode names. Every window's mode line shows the square
575 brackets, since XEmacs as a whole, rather than any particular buffer, is
576 in a recursive edit.
577
578 @findex top-level
579 It is possible to be in recursive edits within recursive edits. For
580 example, after typing @kbd{C-r} in a @code{query-replace}, you might
581 type a command that entered the debugger. In such a case, two or
582 more sets of square brackets appear in the mode line(s). Exiting the
583 inner recursive edit (here with the debugger @kbd{c} command)
584 resumes the query-replace command where it called the debugger. After
585 the end of the query-replace command, you would be able to exit the
586 first recursive edit. Aborting exits only one level of recursive edit;
587 it returns to the command level of the previous recursive edit. You can
588 then abort that one as well.
589
590 The command @kbd{M-x top-level} aborts all levels of
591 recursive edits, returning immediately to the top level command reader.
592
593 The text you edit inside the recursive edit need not be the same text
594 that you were editing at top level. If the command that invokes the
595 recursive edit selects a different buffer first, that is the buffer you
596 will edit recursively. You can switch buffers within the recursive edit
597 in the normal manner (as long as the buffer-switching keys have not been
598 rebound). While you could theoretically do the rest of your editing
599 inside the recursive edit, including visiting files, this could have
600 surprising effects (such as stack overflow) from time to time. It is
601 best if you always exit or abort a recursive edit when you no longer
602 need it.
603
604 In general, XEmacs tries to avoid using recursive edits. It is
605 usually preferable to allow users to switch among the possible editing
606 modes in any order they like. With recursive edits, the only way to get
607 to another state is to go ``back'' to the state that the recursive edit
608 was invoked from.
609
610 @node Dissociated Press, CONX, Recursive Edit, Top
611 @section Dissociated Press
612
613 @findex dissociated-press
614 @kbd{M-x dissociated-press} is a command for scrambling a file of text
615 either word by word or character by character. Starting from a buffer of
616 straight English, it produces extremely amusing output. The input comes
617 from the current XEmacs buffer. Dissociated Press writes its output in a
618 buffer named @samp{*Dissociation*}, and redisplays that buffer after every
619 couple of lines (approximately) to facilitate reading it.
620
621 @code{dissociated-press} asks every so often whether to continue
622 operating. Answer @kbd{n} to stop it. You can also stop at any time by
623 typing @kbd{C-g}. The dissociation output remains in the @samp{*Dissociation*}
624 buffer for you to copy elsewhere if you wish.
625
626 @cindex presidentagon
627 Dissociated Press operates by jumping at random from one point in the
628 buffer to another. In order to produce plausible output rather than
629 gibberish, it insists on a certain amount of overlap between the end of one
630 run of consecutive words or characters and the start of the next. That is,
631 if it has just printed out `president' and then decides to jump to a
632 different point in the file, it might spot the `ent' in `pentagon' and
633 continue from there, producing `presidentagon'. Long sample texts produce
634 the best results.
635
636 @cindex againformation
637 A positive argument to @kbd{M-x dissociated-press} tells it to operate
638 character by character, and specifies the number of overlap characters. A
639 negative argument tells it to operate word by word and specifies the number
640 of overlap words. In this mode, whole words are treated as the elements to
641 be permuted, rather than characters. No argument is equivalent to an
642 argument of two. For your againformation, the output goes only into the
643 buffer @samp{*Dissociation*}. The buffer you start with is not changed.
644
645 @cindex Markov chain
646 @cindex ignoriginal
647 @cindex techniquitous
648 Dissociated Press produces nearly the same results as a Markov chain
649 based on a frequency table constructed from the sample text. It is,
650 however, an independent, ignoriginal invention. Dissociated Press
651 techniquitously copies several consecutive characters from the sample
652 between random choices, whereas a Markov chain would choose randomly for
653 each word or character. This makes for more plausible sounding results
654 and runs faster.
655
656 @cindex outragedy
657 @cindex buggestion
658 @cindex properbose
659 It is a mustatement that too much use of Dissociated Press can be a
660 developediment to your real work. Sometimes to the point of outragedy.
661 And keep dissociwords out of your documentation, if you want it to be well
662 userenced and properbose. Have fun. Your buggestions are welcome.
663
664 @node CONX, Amusements, Dissociated Press, Top
665 @section CONX
666 @cindex random sentences
667
668 Besides producing a file of scrambled text with Dissociated Press, you
669 can generate random sentences by using CONX.
670
671 @table @kbd
672 @item M-x conx
673 Generate random sentences in the @code{*conx*} buffer.
674 @item M-x conx-buffer
675 Absorb the text in the current buffer into the @code{conx} database.
676 @item M-x conx-init
677 Forget the current word-frequency tree.
678 @item M-x conx-load
679 Load a @code{conx} database that has been previously saved with
680 @code{M-x conx-save}.
681 @item M-x conx-region
682 Absorb the text in the current buffer into the @code{conx} database.
683 @item M-x conx-save
684 Save the current @code{conx} database to a file for future retrieval.
685 @end table
686
687 @findex conx
688 @findex conx-buffer
689 @findex conx-load
690 @findex conx-region
691 @findex conx-init
692 @findex conx-save
693
694 Copy text from a buffer using @kbd{M-x conx-buffer} or @kbd{M-x conx-region}
695 and then type @kbd{M-x conx}. Output is continuously generated until you
696 type @key{^G}. You can save the @code{conx} database to a file with
697 @kbd{M-x conx-save}, which you can retrieve with @code{M-x conx-load}.
698 To clear the database, use @code{M-x conx-init}.
699
700 @node Amusements, Emulation, CONX, Top
701 @section Other Amusements
702 @cindex boredom
703 @findex hanoi
704 @findex yow
705
706 If you are a little bit bored, you can try @kbd{M-x hanoi}. If you are
707 considerably bored, give it a numeric argument. If you are very, very
708 bored, try an argument of 9. Sit back and watch.
709
710 When you are frustrated, try the famous Eliza program. Just do
711 @kbd{M-x doctor}. End each input by typing @kbd{RET} twice.
712
713 When you are feeling strange, type @kbd{M-x yow}.
714
715 @node Emulation, Customization, Amusements, Top
716 @comment node-name, next, previous, up
717 @section Emulation
718 @cindex other editors
719 @cindex vi
720 @cindex EDT
721
722 XEmacs can be programmed to emulate (more or less) most other
723 editors. Standard facilities can emulate these:
724
725 @table @asis
726 @item Viper (a vi emulator)
727 @cindex Viper
728 In XEmacs, Viper is the preferred emulation of vi within XEmacs.
729 Viper is designed to allow you to take advantage of the best
730 features of XEmacs while still doing your basic editing in a
731 familiar, vi-like fashion. Viper provides various different
732 levels of vi emulation, from a quite complete emulation that
733 allows almost no access to native XEmacs commands, to an
734 ``expert'' mode that combines the most useful vi commands with
735 the most useful XEmacs commands.
736
737 To start Viper, put the command
738
739 @example
740 (viper-mode)
741 @end example
742
743 in your @file{.emacs} file.
744
745 Viper comes with a separate manual that is provided standard
746 with the XEmacs distribution.
747
748 @ignore
749 @item evi (alternative vi emulator)
750 @cindex evi
751 evi is an alternative vi emulator that also provides a nearly complete
752 emulation of vi.
753
754 evi comes with a separate manual that is provided standard
755 with the XEmacs distribution.
756
757 Warning: loading more than one vi emulator at once may cause name
758 conflicts; no one has checked.
759 @end ignore
760
761 @item EDT (DEC VMS editor)
762 @findex edt-emulation-on
763 @findex edt-emulation-off
764 Turn on EDT emulation with @kbd{M-x edt-emulation-on}. @kbd{M-x
765 @*edt-emulation-off} restores normal Emacs command bindings.
766
767 Most of the EDT emulation commands are keypad keys, and most standard
768 Emacs key bindings are still available. The EDT emulation rebindings
769 are done in the global keymap, so there is no problem switching
770 buffers or major modes while in EDT emulation.
771
772 @item Gosling Emacs
773 @findex set-gosmacs-bindings
774 @findex set-gnu-bindings
775 Turn on emulation of Gosling Emacs (aka Unipress Emacs) with @kbd{M-x
776 set-gosmacs-bindings}. This redefines many keys, mostly on the
777 @kbd{C-x} and @kbd{ESC} prefixes, to work as they do in Gosmacs.
778 @kbd{M-x set-gnu-bindings} returns to normal XEmacs by rebinding
779 the same keys to the definitions they had at the time @kbd{M-x
780 set-gosmacs-bindings} was done.
781
782 It is also possible to run Mocklisp code written for Gosling Emacs.
783 @xref{Mocklisp}.
784 @end table