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1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
f9f59935 | 3 | @c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998 Free Software Foundation, Inc. |
3e01fd9d RS |
4 | @c See the file elisp.texi for copying conditions. |
5 | @setfilename ../info/minibuf | |
3e099569 | 6 | @node Minibuffers, Command Loop, Read and Print, Top |
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7 | @chapter Minibuffers |
8 | @cindex arguments, reading | |
9 | @cindex complex arguments | |
10 | @cindex minibuffer | |
11 | ||
12 | A @dfn{minibuffer} is a special buffer that Emacs commands use to read | |
13 | arguments more complicated than the single numeric prefix argument. | |
14 | These arguments include file names, buffer names, and command names (as | |
15 | in @kbd{M-x}). The minibuffer is displayed on the bottom line of the | |
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16 | frame, in the same place as the echo area, but only while it is in use |
17 | for reading an argument. | |
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18 | |
19 | @menu | |
20 | * Intro to Minibuffers:: Basic information about minibuffers. | |
21 | * Text from Minibuffer:: How to read a straight text string. | |
22 | * Object from Minibuffer:: How to read a Lisp object or expression. | |
23 | * Minibuffer History:: Recording previous minibuffer inputs | |
24 | so the user can reuse them. | |
25 | * Completion:: How to invoke and customize completion. | |
26 | * Yes-or-No Queries:: Asking a question with a simple answer. | |
27 | * Multiple Queries:: Asking a series of similar questions. | |
e75ecfec | 28 | * Reading a Password:: Reading a password from the terminal. |
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29 | * Minibuffer Misc:: Various customization hooks and variables. |
30 | @end menu | |
31 | ||
32 | @node Intro to Minibuffers | |
33 | @section Introduction to Minibuffers | |
34 | ||
35 | In most ways, a minibuffer is a normal Emacs buffer. Most operations | |
36 | @emph{within} a buffer, such as editing commands, work normally in a | |
37 | minibuffer. However, many operations for managing buffers do not apply | |
38 | to minibuffers. The name of a minibuffer always has the form @w{@samp{ | |
39 | *Minibuf-@var{number}}}, and it cannot be changed. Minibuffers are | |
40 | displayed only in special windows used only for minibuffers; these | |
1911e6e5 | 41 | windows always appear at the bottom of a frame. (Sometimes frames have |
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42 | no minibuffer window, and sometimes a special kind of frame contains |
43 | nothing but a minibuffer window; see @ref{Minibuffers and Frames}.) | |
44 | ||
8241495d RS |
45 | The text in the minibuffer always starts with the @dfn{prompt string}, |
46 | the text that was specified by the program that is using the minibuffer | |
47 | to tell the user what sort of input to type. This text is marked | |
48 | read-only so you won't accidentally delete or change it. In other | |
49 | respects, it is an ordinary part of the buffer contents, but certain | |
50 | functions such as @code{erase-buffer}, @code{buffer-string}, | |
51 | @code{beginning-of-line}, @code{forward-word}, @code{forward-sentence}, | |
52 | and @code{forward-paragraph}, treat it a little bit specially. (In | |
53 | older Emacs versions, the prompt was displayed using a special mechanism | |
54 | and was not part of the buffer contents.) | |
55 | ||
56 | @c ??? | |
57 | The minibuffer's window is normally a single line; it grows | |
58 | automatically if necessary if the contents require more space. You can | |
59 | explicitly resize it temporarily with the window sizing commands; it | |
60 | reverts to its normal size when the minibuffer is exited. You can | |
61 | resize it permanently by using the window sizing commands in the frame's | |
62 | other window, when the minibuffer is not active. If the frame contains | |
63 | just a minibuffer, you can change the minibuffer's size by changing the | |
64 | frame's size. | |
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65 | |
66 | If a command uses a minibuffer while there is an active minibuffer, | |
67 | this is called a @dfn{recursive minibuffer}. The first minibuffer is | |
68 | named @w{@samp{ *Minibuf-0*}}. Recursive minibuffers are named by | |
69 | incrementing the number at the end of the name. (The names begin with a | |
70 | space so that they won't show up in normal buffer lists.) Of several | |
71 | recursive minibuffers, the innermost (or most recently entered) is the | |
72 | active minibuffer. We usually call this ``the'' minibuffer. You can | |
73 | permit or forbid recursive minibuffers by setting the variable | |
74 | @code{enable-recursive-minibuffers} or by putting properties of that | |
75 | name on command symbols (@pxref{Minibuffer Misc}). | |
76 | ||
77 | Like other buffers, a minibuffer may use any of several local keymaps | |
78 | (@pxref{Keymaps}); these contain various exit commands and in some cases | |
bfe721d1 | 79 | completion commands (@pxref{Completion}). |
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80 | |
81 | @itemize @bullet | |
82 | @item | |
83 | @code{minibuffer-local-map} is for ordinary input (no completion). | |
84 | ||
85 | @item | |
86 | @code{minibuffer-local-ns-map} is similar, except that @key{SPC} exits | |
87 | just like @key{RET}. This is used mainly for Mocklisp compatibility. | |
88 | ||
89 | @item | |
90 | @code{minibuffer-local-completion-map} is for permissive completion. | |
91 | ||
92 | @item | |
93 | @code{minibuffer-local-must-match-map} is for strict completion and | |
94 | for cautious completion. | |
95 | @end itemize | |
96 | ||
97 | @node Text from Minibuffer | |
98 | @section Reading Text Strings with the Minibuffer | |
99 | ||
793da230 RS |
100 | Most often, the minibuffer is used to read text as a string. It can |
101 | also be used to read a Lisp object in textual form. The most basic | |
102 | primitive for minibuffer input is @code{read-from-minibuffer}; it can do | |
103 | either one. | |
3e01fd9d | 104 | |
bfe721d1 KH |
105 | In most cases, you should not call minibuffer input functions in the |
106 | middle of a Lisp function. Instead, do all minibuffer input as part of | |
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107 | reading the arguments for a command, in the @code{interactive} |
108 | specification. @xref{Defining Commands}. | |
bfe721d1 | 109 | |
f9f59935 | 110 | @defun read-from-minibuffer prompt-string &optional initial-contents keymap read hist default inherit-input-method |
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111 | This function is the most general way to get input through the |
112 | minibuffer. By default, it accepts arbitrary text and returns it as a | |
113 | string; however, if @var{read} is non-@code{nil}, then it uses | |
114 | @code{read} to convert the text into a Lisp object (@pxref{Input | |
115 | Functions}). | |
116 | ||
969fe9b5 | 117 | The first thing this function does is to activate a minibuffer and |
3e01fd9d | 118 | display it with @var{prompt-string} as the prompt. This value must be a |
969fe9b5 | 119 | string. Then the user can edit text in the minibuffer. |
3e01fd9d | 120 | |
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121 | When the user types a command to exit the minibuffer, |
122 | @code{read-from-minibuffer} constructs the return value from the text in | |
123 | the minibuffer. Normally it returns a string containing that text. | |
124 | However, if @var{read} is non-@code{nil}, @code{read-from-minibuffer} | |
125 | reads the text and returns the resulting Lisp object, unevaluated. | |
126 | (@xref{Input Functions}, for information about reading.) | |
f9f59935 | 127 | |
969fe9b5 RS |
128 | The argument @var{default} specifies a default value to make available |
129 | through the history commands. It should be a string, or @code{nil}. If | |
130 | @var{read} is non-@code{nil}, then @var{default} is also used as the | |
131 | input to @code{read}, if the user enters empty input. However, in the | |
a9f0a989 | 132 | usual case (where @var{read} is @code{nil}), @code{read-from-minibuffer} |
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133 | does not return @var{default} when the user enters empty input; it |
134 | returns an empty string, @code{""}. In this respect, it is different | |
135 | from all the other minibuffer input functions in this chapter. | |
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136 | |
137 | If @var{keymap} is non-@code{nil}, that keymap is the local keymap to | |
138 | use in the minibuffer. If @var{keymap} is omitted or @code{nil}, the | |
139 | value of @code{minibuffer-local-map} is used as the keymap. Specifying | |
140 | a keymap is the most important way to customize the minibuffer for | |
141 | various applications such as completion. | |
142 | ||
143 | The argument @var{hist} specifies which history list variable to use | |
144 | for saving the input and for history commands used in the minibuffer. | |
145 | It defaults to @code{minibuffer-history}. @xref{Minibuffer History}. | |
146 | ||
f9f59935 RS |
147 | If the variable @code{minibuffer-allow-text-properties} is |
148 | non-@code{nil}, then the string which is returned includes whatever text | |
149 | properties were present in the minibuffer. Otherwise all the text | |
150 | properties are stripped when the value is returned. | |
151 | ||
f9f59935 | 152 | If the argument @var{inherit-input-method} is non-@code{nil}, then the |
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153 | minibuffer inherits the current input method (@pxref{Input Methods}) and |
154 | the setting of @code{enable-multibyte-characters} (@pxref{Text | |
155 | Representations}) from whichever buffer was current before entering the | |
156 | minibuffer. | |
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157 | |
158 | If @var{initial-contents} is a string, @code{read-from-minibuffer} | |
159 | inserts it into the minibuffer, leaving point at the end, before the | |
160 | user starts to edit the text. The minibuffer appears with this text as | |
161 | its initial contents. | |
162 | ||
163 | Alternatively, @var{initial-contents} can be a cons cell of the form | |
164 | @code{(@var{string} . @var{position})}. This means to insert | |
165 | @var{string} in the minibuffer but put point @var{position} characters | |
166 | from the beginning, rather than at the end. | |
167 | ||
168 | @strong{Usage note:} The @var{initial-contents} argument and the | |
169 | @var{default} argument are two alternative features for more or less the | |
170 | same job. It does not make sense to use both features in a single call | |
171 | to @code{read-from-minibuffer}. In general, we recommend using | |
172 | @var{default}, since this permits the user to insert the default value | |
173 | when it is wanted, but does not burden the user with deleting it from | |
174 | the minibuffer on other occasions. | |
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175 | @end defun |
176 | ||
f9f59935 | 177 | @defun read-string prompt &optional initial history default inherit-input-method |
3e01fd9d RS |
178 | This function reads a string from the minibuffer and returns it. The |
179 | arguments @var{prompt} and @var{initial} are used as in | |
180 | @code{read-from-minibuffer}. The keymap used is | |
181 | @code{minibuffer-local-map}. | |
182 | ||
f9f59935 RS |
183 | The optional argument @var{history}, if non-nil, specifies a history |
184 | list and optionally the initial position in the list. The optional | |
185 | argument @var{default} specifies a default value to return if the user | |
186 | enters null input; it should be a string. The optional argument | |
187 | @var{inherit-input-method} specifies whether to inherit the current | |
188 | buffer's input method. | |
189 | ||
190 | This function is a simplified interface to the | |
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191 | @code{read-from-minibuffer} function: |
192 | ||
193 | @smallexample | |
194 | @group | |
f9f59935 | 195 | (read-string @var{prompt} @var{initial} @var{history} @var{default} @var{inherit}) |
3e01fd9d | 196 | @equiv{} |
969fe9b5 RS |
197 | (let ((value |
198 | (read-from-minibuffer @var{prompt} @var{initial} nil nil | |
199 | @var{history} @var{default} @var{inherit}))) | |
200 | (if (equal value "") | |
201 | @var{default} | |
202 | value)) | |
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203 | @end group |
204 | @end smallexample | |
205 | @end defun | |
206 | ||
f9f59935 | 207 | @defvar minibuffer-allow-text-properties |
1911e6e5 RS |
208 | If this variable is @code{nil}, then @code{read-from-minibuffer} strips |
209 | all text properties from the minibuffer input before returning it. | |
f9f59935 RS |
210 | Since all minibuffer input uses @code{read-from-minibuffer}, this |
211 | variable applies to all minibuffer input. | |
1911e6e5 RS |
212 | |
213 | Note that the completion functions discard text properties unconditionally, | |
214 | regardless of the value of this variable. | |
f9f59935 RS |
215 | @end defvar |
216 | ||
3e01fd9d RS |
217 | @defvar minibuffer-local-map |
218 | This is the default local keymap for reading from the minibuffer. By | |
219 | default, it makes the following bindings: | |
220 | ||
221 | @table @asis | |
969fe9b5 | 222 | @item @kbd{C-j} |
3e01fd9d RS |
223 | @code{exit-minibuffer} |
224 | ||
225 | @item @key{RET} | |
226 | @code{exit-minibuffer} | |
227 | ||
228 | @item @kbd{C-g} | |
229 | @code{abort-recursive-edit} | |
230 | ||
231 | @item @kbd{M-n} | |
232 | @code{next-history-element} | |
233 | ||
234 | @item @kbd{M-p} | |
235 | @code{previous-history-element} | |
236 | ||
237 | @item @kbd{M-r} | |
238 | @code{next-matching-history-element} | |
239 | ||
240 | @item @kbd{M-s} | |
241 | @code{previous-matching-history-element} | |
242 | @end table | |
243 | @end defvar | |
244 | ||
245 | @c In version 18, initial is required | |
246 | @c Emacs 19 feature | |
f9f59935 | 247 | @defun read-no-blanks-input prompt &optional initial inherit-input-method |
3e01fd9d RS |
248 | This function reads a string from the minibuffer, but does not allow |
249 | whitespace characters as part of the input: instead, those characters | |
f9f59935 RS |
250 | terminate the input. The arguments @var{prompt}, @var{initial}, and |
251 | @var{inherit-input-method} are used as in @code{read-from-minibuffer}. | |
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252 | |
253 | This is a simplified interface to the @code{read-from-minibuffer} | |
254 | function, and passes the value of the @code{minibuffer-local-ns-map} | |
255 | keymap as the @var{keymap} argument for that function. Since the keymap | |
256 | @code{minibuffer-local-ns-map} does not rebind @kbd{C-q}, it @emph{is} | |
257 | possible to put a space into the string, by quoting it. | |
258 | ||
259 | @smallexample | |
260 | @group | |
261 | (read-no-blanks-input @var{prompt} @var{initial}) | |
262 | @equiv{} | |
263 | (read-from-minibuffer @var{prompt} @var{initial} minibuffer-local-ns-map) | |
264 | @end group | |
265 | @end smallexample | |
266 | @end defun | |
267 | ||
268 | @defvar minibuffer-local-ns-map | |
269 | This built-in variable is the keymap used as the minibuffer local keymap | |
270 | in the function @code{read-no-blanks-input}. By default, it makes the | |
bfe721d1 | 271 | following bindings, in addition to those of @code{minibuffer-local-map}: |
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272 | |
273 | @table @asis | |
3e01fd9d RS |
274 | @item @key{SPC} |
275 | @cindex @key{SPC} in minibuffer | |
276 | @code{exit-minibuffer} | |
277 | ||
278 | @item @key{TAB} | |
279 | @cindex @key{TAB} in minibuffer | |
280 | @code{exit-minibuffer} | |
281 | ||
3e01fd9d RS |
282 | @item @kbd{?} |
283 | @cindex @kbd{?} in minibuffer | |
284 | @code{self-insert-and-exit} | |
3e01fd9d RS |
285 | @end table |
286 | @end defvar | |
287 | ||
288 | @node Object from Minibuffer | |
289 | @section Reading Lisp Objects with the Minibuffer | |
290 | ||
291 | This section describes functions for reading Lisp objects with the | |
292 | minibuffer. | |
293 | ||
294 | @defun read-minibuffer prompt &optional initial | |
f9f59935 | 295 | This function reads a Lisp object using the minibuffer, and returns it |
3e01fd9d | 296 | without evaluating it. The arguments @var{prompt} and @var{initial} are |
793da230 | 297 | used as in @code{read-from-minibuffer}. |
3e01fd9d | 298 | |
793da230 | 299 | This is a simplified interface to the |
3e01fd9d RS |
300 | @code{read-from-minibuffer} function: |
301 | ||
302 | @smallexample | |
303 | @group | |
304 | (read-minibuffer @var{prompt} @var{initial}) | |
305 | @equiv{} | |
306 | (read-from-minibuffer @var{prompt} @var{initial} nil t) | |
307 | @end group | |
308 | @end smallexample | |
309 | ||
310 | Here is an example in which we supply the string @code{"(testing)"} as | |
311 | initial input: | |
312 | ||
313 | @smallexample | |
314 | @group | |
315 | (read-minibuffer | |
316 | "Enter an expression: " (format "%s" '(testing))) | |
317 | ||
318 | ;; @r{Here is how the minibuffer is displayed:} | |
319 | @end group | |
320 | ||
321 | @group | |
322 | ---------- Buffer: Minibuffer ---------- | |
323 | Enter an expression: (testing)@point{} | |
324 | ---------- Buffer: Minibuffer ---------- | |
325 | @end group | |
326 | @end smallexample | |
327 | ||
328 | @noindent | |
329 | The user can type @key{RET} immediately to use the initial input as a | |
330 | default, or can edit the input. | |
331 | @end defun | |
332 | ||
333 | @defun eval-minibuffer prompt &optional initial | |
f9f59935 RS |
334 | This function reads a Lisp expression using the minibuffer, evaluates |
335 | it, then returns the result. The arguments @var{prompt} and | |
336 | @var{initial} are used as in @code{read-from-minibuffer}. | |
3e01fd9d | 337 | |
793da230 | 338 | This function simply evaluates the result of a call to |
3e01fd9d RS |
339 | @code{read-minibuffer}: |
340 | ||
341 | @smallexample | |
342 | @group | |
343 | (eval-minibuffer @var{prompt} @var{initial}) | |
344 | @equiv{} | |
345 | (eval (read-minibuffer @var{prompt} @var{initial})) | |
346 | @end group | |
347 | @end smallexample | |
348 | @end defun | |
349 | ||
350 | @defun edit-and-eval-command prompt form | |
793da230 | 351 | This function reads a Lisp expression in the minibuffer, and then |
3e01fd9d RS |
352 | evaluates it. The difference between this command and |
353 | @code{eval-minibuffer} is that here the initial @var{form} is not | |
354 | optional and it is treated as a Lisp object to be converted to printed | |
355 | representation rather than as a string of text. It is printed with | |
356 | @code{prin1}, so if it is a string, double-quote characters (@samp{"}) | |
357 | appear in the initial text. @xref{Output Functions}. | |
358 | ||
793da230 | 359 | The first thing @code{edit-and-eval-command} does is to activate the |
3e01fd9d | 360 | minibuffer with @var{prompt} as the prompt. Then it inserts the printed |
f9f59935 | 361 | representation of @var{form} in the minibuffer, and lets the user edit it. |
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362 | When the user exits the minibuffer, the edited text is read with |
363 | @code{read} and then evaluated. The resulting value becomes the value | |
364 | of @code{edit-and-eval-command}. | |
365 | ||
793da230 | 366 | In the following example, we offer the user an expression with initial |
3e01fd9d RS |
367 | text which is a valid form already: |
368 | ||
369 | @smallexample | |
370 | @group | |
371 | (edit-and-eval-command "Please edit: " '(forward-word 1)) | |
372 | ||
793da230 | 373 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
374 | ;; @r{the following appears in the minibuffer:} |
375 | @end group | |
376 | ||
377 | @group | |
378 | ---------- Buffer: Minibuffer ---------- | |
379 | Please edit: (forward-word 1)@point{} | |
380 | ---------- Buffer: Minibuffer ---------- | |
381 | @end group | |
382 | @end smallexample | |
383 | ||
384 | @noindent | |
385 | Typing @key{RET} right away would exit the minibuffer and evaluate the | |
386 | expression, thus moving point forward one word. | |
387 | @code{edit-and-eval-command} returns @code{nil} in this example. | |
388 | @end defun | |
389 | ||
390 | @node Minibuffer History | |
391 | @section Minibuffer History | |
392 | @cindex minibuffer history | |
393 | @cindex history list | |
394 | ||
969fe9b5 | 395 | A @dfn{minibuffer history list} records previous minibuffer inputs so |
793da230 RS |
396 | the user can reuse them conveniently. A history list is actually a |
397 | symbol, not a list; it is a variable whose value is a list of strings | |
398 | (previous inputs), most recent first. | |
3e01fd9d | 399 | |
969fe9b5 | 400 | There are many separate history lists, used for different kinds of |
3e01fd9d RS |
401 | inputs. It's the Lisp programmer's job to specify the right history |
402 | list for each use of the minibuffer. | |
403 | ||
969fe9b5 | 404 | The basic minibuffer input functions @code{read-from-minibuffer} and |
3e01fd9d RS |
405 | @code{completing-read} both accept an optional argument named @var{hist} |
406 | which is how you specify the history list. Here are the possible | |
407 | values: | |
408 | ||
409 | @table @asis | |
410 | @item @var{variable} | |
411 | Use @var{variable} (a symbol) as the history list. | |
412 | ||
413 | @item (@var{variable} . @var{startpos}) | |
414 | Use @var{variable} (a symbol) as the history list, and assume that the | |
415 | initial history position is @var{startpos} (an integer, counting from | |
416 | zero which specifies the most recent element of the history). | |
417 | ||
418 | If you specify @var{startpos}, then you should also specify that element | |
419 | of the history as the initial minibuffer contents, for consistency. | |
420 | @end table | |
421 | ||
969fe9b5 | 422 | If you don't specify @var{hist}, then the default history list |
3e01fd9d RS |
423 | @code{minibuffer-history} is used. For other standard history lists, |
424 | see below. You can also create your own history list variable; just | |
425 | initialize it to @code{nil} before the first use. | |
426 | ||
969fe9b5 | 427 | Both @code{read-from-minibuffer} and @code{completing-read} add new |
3e01fd9d RS |
428 | elements to the history list automatically, and provide commands to |
429 | allow the user to reuse items on the list. The only thing your program | |
430 | needs to do to use a history list is to initialize it and to pass its | |
431 | name to the input functions when you wish. But it is safe to modify the | |
432 | list by hand when the minibuffer input functions are not using it. | |
433 | ||
969fe9b5 RS |
434 | Here are some of the standard minibuffer history list variables: |
435 | ||
3e01fd9d RS |
436 | @defvar minibuffer-history |
437 | The default history list for minibuffer history input. | |
438 | @end defvar | |
439 | ||
440 | @defvar query-replace-history | |
441 | A history list for arguments to @code{query-replace} (and similar | |
442 | arguments to other commands). | |
443 | @end defvar | |
444 | ||
445 | @defvar file-name-history | |
a9f0a989 RS |
446 | A history list for file-name arguments. |
447 | @end defvar | |
448 | ||
449 | @defvar buffer-name-history | |
450 | @tindex buffer-name-history | |
451 | A history list for buffer-name arguments. | |
3e01fd9d RS |
452 | @end defvar |
453 | ||
454 | @defvar regexp-history | |
455 | A history list for regular expression arguments. | |
456 | @end defvar | |
457 | ||
458 | @defvar extended-command-history | |
459 | A history list for arguments that are names of extended commands. | |
460 | @end defvar | |
461 | ||
462 | @defvar shell-command-history | |
463 | A history list for arguments that are shell commands. | |
464 | @end defvar | |
465 | ||
466 | @defvar read-expression-history | |
467 | A history list for arguments that are Lisp expressions to evaluate. | |
468 | @end defvar | |
469 | ||
470 | @node Completion | |
471 | @section Completion | |
472 | @cindex completion | |
473 | ||
474 | @dfn{Completion} is a feature that fills in the rest of a name | |
475 | starting from an abbreviation for it. Completion works by comparing the | |
476 | user's input against a list of valid names and determining how much of | |
477 | the name is determined uniquely by what the user has typed. For | |
478 | example, when you type @kbd{C-x b} (@code{switch-to-buffer}) and then | |
479 | type the first few letters of the name of the buffer to which you wish | |
480 | to switch, and then type @key{TAB} (@code{minibuffer-complete}), Emacs | |
481 | extends the name as far as it can. | |
482 | ||
483 | Standard Emacs commands offer completion for names of symbols, files, | |
484 | buffers, and processes; with the functions in this section, you can | |
485 | implement completion for other kinds of names. | |
486 | ||
487 | The @code{try-completion} function is the basic primitive for | |
488 | completion: it returns the longest determined completion of a given | |
489 | initial string, with a given set of strings to match against. | |
490 | ||
491 | The function @code{completing-read} provides a higher-level interface | |
492 | for completion. A call to @code{completing-read} specifies how to | |
493 | determine the list of valid names. The function then activates the | |
494 | minibuffer with a local keymap that binds a few keys to commands useful | |
495 | for completion. Other functions provide convenient simple interfaces | |
496 | for reading certain kinds of names with completion. | |
497 | ||
498 | @menu | |
499 | * Basic Completion:: Low-level functions for completing strings. | |
500 | (These are too low level to use the minibuffer.) | |
501 | * Minibuffer Completion:: Invoking the minibuffer with completion. | |
502 | * Completion Commands:: Minibuffer commands that do completion. | |
503 | * High-Level Completion:: Convenient special cases of completion | |
504 | (reading buffer name, file name, etc.) | |
505 | * Reading File Names:: Using completion to read file names. | |
506 | * Programmed Completion:: Finding the completions for a given file name. | |
507 | @end menu | |
508 | ||
509 | @node Basic Completion | |
510 | @subsection Basic Completion Functions | |
511 | ||
793da230 RS |
512 | The two functions @code{try-completion} and @code{all-completions} |
513 | have nothing in themselves to do with minibuffers. We describe them in | |
514 | this chapter so as to keep them near the higher-level completion | |
515 | features that do use the minibuffer. | |
516 | ||
3e01fd9d RS |
517 | @defun try-completion string collection &optional predicate |
518 | This function returns the longest common substring of all possible | |
519 | completions of @var{string} in @var{collection}. The value of | |
793da230 | 520 | @var{collection} must be an alist, an obarray, or a function that |
3e01fd9d RS |
521 | implements a virtual set of strings (see below). |
522 | ||
523 | Completion compares @var{string} against each of the permissible | |
524 | completions specified by @var{collection}; if the beginning of the | |
525 | permissible completion equals @var{string}, it matches. If no permissible | |
526 | completions match, @code{try-completion} returns @code{nil}. If only | |
527 | one permissible completion matches, and the match is exact, then | |
528 | @code{try-completion} returns @code{t}. Otherwise, the value is the | |
529 | longest initial sequence common to all the permissible completions that | |
530 | match. | |
531 | ||
532 | If @var{collection} is an alist (@pxref{Association Lists}), the | |
533 | @sc{car}s of the alist elements form the set of permissible completions. | |
534 | ||
535 | @cindex obarray in completion | |
536 | If @var{collection} is an obarray (@pxref{Creating Symbols}), the names | |
537 | of all symbols in the obarray form the set of permissible completions. The | |
538 | global variable @code{obarray} holds an obarray containing the names of | |
539 | all interned Lisp symbols. | |
540 | ||
541 | Note that the only valid way to make a new obarray is to create it | |
542 | empty and then add symbols to it one by one using @code{intern}. | |
543 | Also, you cannot intern a given symbol in more than one obarray. | |
544 | ||
545 | If the argument @var{predicate} is non-@code{nil}, then it must be a | |
546 | function of one argument. It is used to test each possible match, and | |
547 | the match is accepted only if @var{predicate} returns non-@code{nil}. | |
548 | The argument given to @var{predicate} is either a cons cell from the alist | |
549 | (the @sc{car} of which is a string) or else it is a symbol (@emph{not} a | |
550 | symbol name) from the obarray. | |
551 | ||
793da230 RS |
552 | You can also use a symbol that is a function as @var{collection}. Then |
553 | the function is solely responsible for performing completion; | |
3e01fd9d RS |
554 | @code{try-completion} returns whatever this function returns. The |
555 | function is called with three arguments: @var{string}, @var{predicate} | |
556 | and @code{nil}. (The reason for the third argument is so that the same | |
557 | function can be used in @code{all-completions} and do the appropriate | |
558 | thing in either case.) @xref{Programmed Completion}. | |
559 | ||
560 | In the first of the following examples, the string @samp{foo} is | |
561 | matched by three of the alist @sc{car}s. All of the matches begin with | |
562 | the characters @samp{fooba}, so that is the result. In the second | |
563 | example, there is only one possible match, and it is exact, so the value | |
564 | is @code{t}. | |
565 | ||
566 | @smallexample | |
567 | @group | |
568 | (try-completion | |
569 | "foo" | |
570 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))) | |
571 | @result{} "fooba" | |
572 | @end group | |
573 | ||
574 | @group | |
575 | (try-completion "foo" '(("barfoo" 2) ("foo" 3))) | |
576 | @result{} t | |
577 | @end group | |
578 | @end smallexample | |
579 | ||
580 | In the following example, numerous symbols begin with the characters | |
581 | @samp{forw}, and all of them begin with the word @samp{forward}. In | |
582 | most of the symbols, this is followed with a @samp{-}, but not in all, | |
583 | so no more than @samp{forward} can be completed. | |
584 | ||
585 | @smallexample | |
586 | @group | |
587 | (try-completion "forw" obarray) | |
588 | @result{} "forward" | |
589 | @end group | |
590 | @end smallexample | |
591 | ||
592 | Finally, in the following example, only two of the three possible | |
593 | matches pass the predicate @code{test} (the string @samp{foobaz} is | |
594 | too short). Both of those begin with the string @samp{foobar}. | |
595 | ||
596 | @smallexample | |
597 | @group | |
598 | (defun test (s) | |
599 | (> (length (car s)) 6)) | |
600 | @result{} test | |
601 | @end group | |
602 | @group | |
603 | (try-completion | |
604 | "foo" | |
605 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) | |
793da230 | 606 | 'test) |
3e01fd9d RS |
607 | @result{} "foobar" |
608 | @end group | |
609 | @end smallexample | |
610 | @end defun | |
611 | ||
22697dac | 612 | @defun all-completions string collection &optional predicate nospace |
3e01fd9d | 613 | This function returns a list of all possible completions of |
969fe9b5 | 614 | @var{string}. The arguments to this function are the same as those of |
3e01fd9d RS |
615 | @code{try-completion}. |
616 | ||
617 | If @var{collection} is a function, it is called with three arguments: | |
618 | @var{string}, @var{predicate} and @code{t}; then @code{all-completions} | |
619 | returns whatever the function returns. @xref{Programmed Completion}. | |
620 | ||
22697dac KH |
621 | If @var{nospace} is non-@code{nil}, completions that start with a space |
622 | are ignored unless @var{string} also starts with a space. | |
623 | ||
3e01fd9d RS |
624 | Here is an example, using the function @code{test} shown in the |
625 | example for @code{try-completion}: | |
626 | ||
627 | @smallexample | |
628 | @group | |
629 | (defun test (s) | |
630 | (> (length (car s)) 6)) | |
631 | @result{} test | |
632 | @end group | |
633 | ||
634 | @group | |
635 | (all-completions | |
636 | "foo" | |
637 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) | |
793da230 | 638 | 'test) |
3e01fd9d RS |
639 | @result{} ("foobar1" "foobar2") |
640 | @end group | |
641 | @end smallexample | |
642 | @end defun | |
643 | ||
644 | @defvar completion-ignore-case | |
645 | If the value of this variable is | |
646 | non-@code{nil}, Emacs does not consider case significant in completion. | |
647 | @end defvar | |
648 | ||
3e01fd9d RS |
649 | @node Minibuffer Completion |
650 | @subsection Completion and the Minibuffer | |
651 | ||
652 | This section describes the basic interface for reading from the | |
653 | minibuffer with completion. | |
654 | ||
f9f59935 | 655 | @defun completing-read prompt collection &optional predicate require-match initial hist default inherit-input-method |
3e01fd9d RS |
656 | This function reads a string in the minibuffer, assisting the user by |
657 | providing completion. It activates the minibuffer with prompt | |
969fe9b5 | 658 | @var{prompt}, which must be a string. |
3e01fd9d RS |
659 | |
660 | The actual completion is done by passing @var{collection} and | |
661 | @var{predicate} to the function @code{try-completion}. This happens in | |
662 | certain commands bound in the local keymaps used for completion. | |
663 | ||
f9f59935 RS |
664 | If @var{require-match} is @code{nil}, the exit commands work regardless |
665 | of the input in the minibuffer. If @var{require-match} is @code{t}, the | |
666 | usual minibuffer exit commands won't exit unless the input completes to | |
667 | an element of @var{collection}. If @var{require-match} is neither | |
668 | @code{nil} nor @code{t}, then the exit commands won't exit unless the | |
669 | input already in the buffer matches an element of @var{collection}. | |
670 | ||
671 | However, empty input is always permitted, regardless of the value of | |
672 | @var{require-match}; in that case, @code{completing-read} returns | |
969fe9b5 RS |
673 | @var{default}. The value of @var{default} (if non-@code{nil}) is also |
674 | available to the user through the history commands. | |
3e01fd9d | 675 | |
ece23c27 | 676 | The user can exit with null input by typing @key{RET} with an empty |
6ecb21f1 RS |
677 | minibuffer. Then @code{completing-read} returns @code{""}. This is how |
678 | the user requests whatever default the command uses for the value being | |
679 | read. The user can return using @key{RET} in this way regardless of the | |
680 | value of @var{require-match}, and regardless of whether the empty string | |
681 | is included in @var{collection}. | |
ece23c27 | 682 | |
3e01fd9d RS |
683 | The function @code{completing-read} works by calling |
684 | @code{read-minibuffer}. It uses @code{minibuffer-local-completion-map} | |
685 | as the keymap if @var{require-match} is @code{nil}, and uses | |
686 | @code{minibuffer-local-must-match-map} if @var{require-match} is | |
793da230 | 687 | non-@code{nil}. @xref{Completion Commands}. |
3e01fd9d RS |
688 | |
689 | The argument @var{hist} specifies which history list variable to use for | |
690 | saving the input and for minibuffer history commands. It defaults to | |
691 | @code{minibuffer-history}. @xref{Minibuffer History}. | |
692 | ||
969fe9b5 RS |
693 | If @var{initial} is non-@code{nil}, @code{completing-read} inserts it |
694 | into the minibuffer as part of the input. Then it allows the user to | |
695 | edit the input, providing several commands to attempt completion. | |
696 | In most cases, we recommend using @var{default}, and not @var{initial}. | |
f9f59935 RS |
697 | |
698 | If the argument @var{inherit-input-method} is non-@code{nil}, then the | |
1911e6e5 | 699 | minibuffer inherits the current input method (@pxref{Input |
a9f0a989 RS |
700 | Methods}) and the setting of @code{enable-multibyte-characters} |
701 | (@pxref{Text Representations}) from whichever buffer was current before | |
702 | entering the minibuffer. | |
f9f59935 | 703 | |
3e01fd9d RS |
704 | Completion ignores case when comparing the input against the possible |
705 | matches, if the built-in variable @code{completion-ignore-case} is | |
706 | non-@code{nil}. @xref{Basic Completion}. | |
707 | ||
708 | Here's an example of using @code{completing-read}: | |
709 | ||
710 | @smallexample | |
711 | @group | |
712 | (completing-read | |
713 | "Complete a foo: " | |
714 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) | |
715 | nil t "fo") | |
716 | @end group | |
717 | ||
718 | @group | |
793da230 | 719 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
720 | ;; @r{the following appears in the minibuffer:} |
721 | ||
722 | ---------- Buffer: Minibuffer ---------- | |
723 | Complete a foo: fo@point{} | |
724 | ---------- Buffer: Minibuffer ---------- | |
725 | @end group | |
726 | @end smallexample | |
727 | ||
728 | @noindent | |
729 | If the user then types @kbd{@key{DEL} @key{DEL} b @key{RET}}, | |
730 | @code{completing-read} returns @code{barfoo}. | |
731 | ||
732 | The @code{completing-read} function binds three variables to pass | |
793da230 RS |
733 | information to the commands that actually do completion. These |
734 | variables are @code{minibuffer-completion-table}, | |
735 | @code{minibuffer-completion-predicate} and | |
736 | @code{minibuffer-completion-confirm}. For more information about them, | |
737 | see @ref{Completion Commands}. | |
3e01fd9d RS |
738 | @end defun |
739 | ||
740 | @node Completion Commands | |
8241495d | 741 | @subsection Minibuffer Commands that Do Completion |
3e01fd9d RS |
742 | |
743 | This section describes the keymaps, commands and user options used in | |
744 | the minibuffer to do completion. | |
745 | ||
746 | @defvar minibuffer-local-completion-map | |
793da230 | 747 | @code{completing-read} uses this value as the local keymap when an |
3e01fd9d RS |
748 | exact match of one of the completions is not required. By default, this |
749 | keymap makes the following bindings: | |
750 | ||
751 | @table @asis | |
752 | @item @kbd{?} | |
753 | @code{minibuffer-completion-help} | |
754 | ||
755 | @item @key{SPC} | |
756 | @code{minibuffer-complete-word} | |
757 | ||
758 | @item @key{TAB} | |
759 | @code{minibuffer-complete} | |
760 | @end table | |
761 | ||
762 | @noindent | |
793da230 RS |
763 | with other characters bound as in @code{minibuffer-local-map} |
764 | (@pxref{Text from Minibuffer}). | |
3e01fd9d RS |
765 | @end defvar |
766 | ||
767 | @defvar minibuffer-local-must-match-map | |
768 | @code{completing-read} uses this value as the local keymap when an | |
769 | exact match of one of the completions is required. Therefore, no keys | |
793da230 | 770 | are bound to @code{exit-minibuffer}, the command that exits the |
3e01fd9d RS |
771 | minibuffer unconditionally. By default, this keymap makes the following |
772 | bindings: | |
773 | ||
774 | @table @asis | |
775 | @item @kbd{?} | |
776 | @code{minibuffer-completion-help} | |
777 | ||
778 | @item @key{SPC} | |
779 | @code{minibuffer-complete-word} | |
780 | ||
781 | @item @key{TAB} | |
782 | @code{minibuffer-complete} | |
783 | ||
969fe9b5 | 784 | @item @kbd{C-j} |
3e01fd9d RS |
785 | @code{minibuffer-complete-and-exit} |
786 | ||
787 | @item @key{RET} | |
788 | @code{minibuffer-complete-and-exit} | |
789 | @end table | |
790 | ||
791 | @noindent | |
792 | with other characters bound as in @code{minibuffer-local-map}. | |
793 | @end defvar | |
794 | ||
795 | @defvar minibuffer-completion-table | |
796 | The value of this variable is the alist or obarray used for completion | |
797 | in the minibuffer. This is the global variable that contains what | |
798 | @code{completing-read} passes to @code{try-completion}. It is used by | |
799 | minibuffer completion commands such as @code{minibuffer-complete-word}. | |
800 | @end defvar | |
801 | ||
802 | @defvar minibuffer-completion-predicate | |
803 | This variable's value is the predicate that @code{completing-read} | |
804 | passes to @code{try-completion}. The variable is also used by the other | |
805 | minibuffer completion functions. | |
806 | @end defvar | |
807 | ||
808 | @deffn Command minibuffer-complete-word | |
809 | This function completes the minibuffer contents by at most a single | |
810 | word. Even if the minibuffer contents have only one completion, | |
811 | @code{minibuffer-complete-word} does not add any characters beyond the | |
812 | first character that is not a word constituent. @xref{Syntax Tables}. | |
813 | @end deffn | |
814 | ||
815 | @deffn Command minibuffer-complete | |
816 | This function completes the minibuffer contents as far as possible. | |
817 | @end deffn | |
818 | ||
819 | @deffn Command minibuffer-complete-and-exit | |
820 | This function completes the minibuffer contents, and exits if | |
821 | confirmation is not required, i.e., if | |
2770e862 | 822 | @code{minibuffer-completion-confirm} is @code{nil}. If confirmation |
793da230 RS |
823 | @emph{is} required, it is given by repeating this command |
824 | immediately---the command is programmed to work without confirmation | |
825 | when run twice in succession. | |
3e01fd9d RS |
826 | @end deffn |
827 | ||
828 | @defvar minibuffer-completion-confirm | |
829 | When the value of this variable is non-@code{nil}, Emacs asks for | |
830 | confirmation of a completion before exiting the minibuffer. The | |
831 | function @code{minibuffer-complete-and-exit} checks the value of this | |
832 | variable before it exits. | |
833 | @end defvar | |
834 | ||
835 | @deffn Command minibuffer-completion-help | |
836 | This function creates a list of the possible completions of the | |
837 | current minibuffer contents. It works by calling @code{all-completions} | |
838 | using the value of the variable @code{minibuffer-completion-table} as | |
839 | the @var{collection} argument, and the value of | |
840 | @code{minibuffer-completion-predicate} as the @var{predicate} argument. | |
841 | The list of completions is displayed as text in a buffer named | |
842 | @samp{*Completions*}. | |
843 | @end deffn | |
844 | ||
845 | @defun display-completion-list completions | |
846 | This function displays @var{completions} to the stream in | |
3e099569 | 847 | @code{standard-output}, usually a buffer. (@xref{Read and Print}, for more |
3e01fd9d RS |
848 | information about streams.) The argument @var{completions} is normally |
849 | a list of completions just returned by @code{all-completions}, but it | |
850 | does not have to be. Each element may be a symbol or a string, either | |
851 | of which is simply printed, or a list of two strings, which is printed | |
852 | as if the strings were concatenated. | |
853 | ||
854 | This function is called by @code{minibuffer-completion-help}. The | |
855 | most common way to use it is together with | |
856 | @code{with-output-to-temp-buffer}, like this: | |
857 | ||
858 | @example | |
859 | (with-output-to-temp-buffer "*Completions*" | |
860 | (display-completion-list | |
861 | (all-completions (buffer-string) my-alist))) | |
862 | @end example | |
863 | @end defun | |
864 | ||
865 | @defopt completion-auto-help | |
866 | If this variable is non-@code{nil}, the completion commands | |
867 | automatically display a list of possible completions whenever nothing | |
868 | can be completed because the next character is not uniquely determined. | |
869 | @end defopt | |
870 | ||
871 | @node High-Level Completion | |
872 | @subsection High-Level Completion Functions | |
873 | ||
874 | This section describes the higher-level convenient functions for | |
875 | reading certain sorts of names with completion. | |
876 | ||
bfe721d1 KH |
877 | In most cases, you should not call these functions in the middle of a |
878 | Lisp function. When possible, do all minibuffer input as part of | |
a9f0a989 RS |
879 | reading the arguments for a command, in the @code{interactive} |
880 | specification. @xref{Defining Commands}. | |
bfe721d1 | 881 | |
3e01fd9d RS |
882 | @defun read-buffer prompt &optional default existing |
883 | This function reads the name of a buffer and returns it as a string. | |
884 | The argument @var{default} is the default name to use, the value to | |
885 | return if the user exits with an empty minibuffer. If non-@code{nil}, | |
886 | it should be a string or a buffer. It is mentioned in the prompt, but | |
887 | is not inserted in the minibuffer as initial input. | |
888 | ||
889 | If @var{existing} is non-@code{nil}, then the name specified must be | |
793da230 RS |
890 | that of an existing buffer. The usual commands to exit the minibuffer |
891 | do not exit if the text is not valid, and @key{RET} does completion to | |
892 | attempt to find a valid name. (However, @var{default} is not checked | |
893 | for validity; it is returned, whatever it is, if the user exits with the | |
894 | minibuffer empty.) | |
3e01fd9d RS |
895 | |
896 | In the following example, the user enters @samp{minibuffer.t}, and | |
897 | then types @key{RET}. The argument @var{existing} is @code{t}, and the | |
898 | only buffer name starting with the given input is | |
899 | @samp{minibuffer.texi}, so that name is the value. | |
900 | ||
901 | @example | |
902 | (read-buffer "Buffer name? " "foo" t) | |
903 | @group | |
793da230 | 904 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
905 | ;; @r{the following prompt appears,} |
906 | ;; @r{with an empty minibuffer:} | |
907 | @end group | |
908 | ||
909 | @group | |
910 | ---------- Buffer: Minibuffer ---------- | |
911 | Buffer name? (default foo) @point{} | |
912 | ---------- Buffer: Minibuffer ---------- | |
913 | @end group | |
914 | ||
915 | @group | |
916 | ;; @r{The user types @kbd{minibuffer.t @key{RET}}.} | |
917 | @result{} "minibuffer.texi" | |
918 | @end group | |
919 | @end example | |
920 | @end defun | |
921 | ||
f9f59935 RS |
922 | @defvar read-buffer-function |
923 | This variable specifies how to read buffer names. For example, if you | |
924 | set this variable to @code{iswitchb-read-buffer}, all Emacs commands | |
925 | that call @code{read-buffer} to read a buffer name will actually use the | |
926 | @code{iswitchb} package to read it. | |
927 | @end defvar | |
928 | ||
929 | @defun read-command prompt &optional default | |
3e01fd9d RS |
930 | This function reads the name of a command and returns it as a Lisp |
931 | symbol. The argument @var{prompt} is used as in | |
932 | @code{read-from-minibuffer}. Recall that a command is anything for | |
933 | which @code{commandp} returns @code{t}, and a command name is a symbol | |
934 | for which @code{commandp} returns @code{t}. @xref{Interactive Call}. | |
935 | ||
f9f59935 | 936 | The argument @var{default} specifies what to return if the user enters |
969fe9b5 RS |
937 | null input. It can be a symbol or a string; if it is a string, |
938 | @code{read-command} interns it before returning it. If @var{default} is | |
939 | @code{nil}, that means no default has been specified; then if the user | |
940 | enters null input, the return value is @code{nil}. | |
f9f59935 | 941 | |
3e01fd9d RS |
942 | @example |
943 | (read-command "Command name? ") | |
944 | ||
945 | @group | |
793da230 | 946 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
947 | ;; @r{the following prompt appears with an empty minibuffer:} |
948 | @end group | |
949 | ||
950 | @group | |
951 | ---------- Buffer: Minibuffer ---------- | |
952 | Command name? | |
953 | ---------- Buffer: Minibuffer ---------- | |
954 | @end group | |
955 | @end example | |
956 | ||
957 | @noindent | |
958 | If the user types @kbd{forward-c @key{RET}}, then this function returns | |
959 | @code{forward-char}. | |
960 | ||
9e2b495b RS |
961 | The @code{read-command} function is a simplified interface to |
962 | @code{completing-read}. It uses the variable @code{obarray} so as to | |
963 | complete in the set of extant Lisp symbols, and it uses the | |
3e01fd9d RS |
964 | @code{commandp} predicate so as to accept only command names: |
965 | ||
966 | @cindex @code{commandp} example | |
967 | @example | |
968 | @group | |
969 | (read-command @var{prompt}) | |
970 | @equiv{} | |
971 | (intern (completing-read @var{prompt} obarray | |
972 | 'commandp t nil)) | |
973 | @end group | |
974 | @end example | |
975 | @end defun | |
976 | ||
f9f59935 | 977 | @defun read-variable prompt &optional default |
3e01fd9d RS |
978 | This function reads the name of a user variable and returns it as a |
979 | symbol. | |
980 | ||
f9f59935 | 981 | The argument @var{default} specifies what to return if the user enters |
969fe9b5 RS |
982 | null input. It can be a symbol or a string; if it is a string, |
983 | @code{read-variable} interns it before returning it. If @var{default} | |
984 | is @code{nil}, that means no default has been specified; then if the | |
985 | user enters null input, the return value is @code{nil}. | |
f9f59935 | 986 | |
3e01fd9d RS |
987 | @example |
988 | @group | |
989 | (read-variable "Variable name? ") | |
990 | ||
793da230 | 991 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
992 | ;; @r{the following prompt appears,} |
993 | ;; @r{with an empty minibuffer:} | |
994 | @end group | |
995 | ||
996 | @group | |
997 | ---------- Buffer: Minibuffer ---------- | |
998 | Variable name? @point{} | |
999 | ---------- Buffer: Minibuffer ---------- | |
1000 | @end group | |
1001 | @end example | |
1002 | ||
1003 | @noindent | |
1004 | If the user then types @kbd{fill-p @key{RET}}, @code{read-variable} | |
1005 | returns @code{fill-prefix}. | |
1006 | ||
1007 | This function is similar to @code{read-command}, but uses the | |
1008 | predicate @code{user-variable-p} instead of @code{commandp}: | |
1009 | ||
1010 | @cindex @code{user-variable-p} example | |
1011 | @example | |
1012 | @group | |
1013 | (read-variable @var{prompt}) | |
1014 | @equiv{} | |
1015 | (intern | |
1016 | (completing-read @var{prompt} obarray | |
1017 | 'user-variable-p t nil)) | |
1018 | @end group | |
1019 | @end example | |
1020 | @end defun | |
1021 | ||
969fe9b5 | 1022 | See also the functions @code{read-coding-system} and |
1911e6e5 | 1023 | @code{read-non-nil-coding-system}, in @ref{User-Chosen Coding Systems}. |
f9f59935 | 1024 | |
3e01fd9d RS |
1025 | @node Reading File Names |
1026 | @subsection Reading File Names | |
1027 | ||
1028 | Here is another high-level completion function, designed for reading a | |
1029 | file name. It provides special features including automatic insertion | |
1030 | of the default directory. | |
1031 | ||
1032 | @defun read-file-name prompt &optional directory default existing initial | |
1033 | This function reads a file name in the minibuffer, prompting with | |
1034 | @var{prompt} and providing completion. If @var{default} is | |
1035 | non-@code{nil}, then the function returns @var{default} if the user just | |
793da230 RS |
1036 | types @key{RET}. @var{default} is not checked for validity; it is |
1037 | returned, whatever it is, if the user exits with the minibuffer empty. | |
3e01fd9d | 1038 | |
793da230 RS |
1039 | If @var{existing} is non-@code{nil}, then the user must specify the name |
1040 | of an existing file; @key{RET} performs completion to make the name | |
1041 | valid if possible, and then refuses to exit if it is not valid. If the | |
1042 | value of @var{existing} is neither @code{nil} nor @code{t}, then | |
1043 | @key{RET} also requires confirmation after completion. If | |
1044 | @var{existing} is @code{nil}, then the name of a nonexistent file is | |
1045 | acceptable. | |
3e01fd9d RS |
1046 | |
1047 | The argument @var{directory} specifies the directory to use for | |
793da230 RS |
1048 | completion of relative file names. If @code{insert-default-directory} |
1049 | is non-@code{nil}, @var{directory} is also inserted in the minibuffer as | |
1050 | initial input. It defaults to the current buffer's value of | |
1051 | @code{default-directory}. | |
3e01fd9d RS |
1052 | |
1053 | @c Emacs 19 feature | |
1054 | If you specify @var{initial}, that is an initial file name to insert in | |
1911e6e5 | 1055 | the buffer (after @var{directory}, if that is inserted). In this |
793da230 RS |
1056 | case, point goes at the beginning of @var{initial}. The default for |
1057 | @var{initial} is @code{nil}---don't insert any file name. To see what | |
969fe9b5 RS |
1058 | @var{initial} does, try the command @kbd{C-x C-v}. @strong{Note:} we |
1059 | recommend using @var{default} rather than @var{initial} in most cases. | |
3e01fd9d RS |
1060 | |
1061 | Here is an example: | |
1062 | ||
1063 | @example | |
1064 | @group | |
1065 | (read-file-name "The file is ") | |
1066 | ||
793da230 | 1067 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
1068 | ;; @r{the following appears in the minibuffer:} |
1069 | @end group | |
1070 | ||
1071 | @group | |
1072 | ---------- Buffer: Minibuffer ---------- | |
1073 | The file is /gp/gnu/elisp/@point{} | |
1074 | ---------- Buffer: Minibuffer ---------- | |
1075 | @end group | |
1076 | @end example | |
1077 | ||
1078 | @noindent | |
1079 | Typing @kbd{manual @key{TAB}} results in the following: | |
1080 | ||
1081 | @example | |
1082 | @group | |
1083 | ---------- Buffer: Minibuffer ---------- | |
1084 | The file is /gp/gnu/elisp/manual.texi@point{} | |
1085 | ---------- Buffer: Minibuffer ---------- | |
1086 | @end group | |
1087 | @end example | |
1088 | ||
1089 | @c Wordy to avoid overfull hbox in smallbook mode. | |
1090 | @noindent | |
1091 | If the user types @key{RET}, @code{read-file-name} returns the file name | |
1092 | as the string @code{"/gp/gnu/elisp/manual.texi"}. | |
1093 | @end defun | |
1094 | ||
1095 | @defopt insert-default-directory | |
1096 | This variable is used by @code{read-file-name}. Its value controls | |
1097 | whether @code{read-file-name} starts by placing the name of the default | |
1098 | directory in the minibuffer, plus the initial file name if any. If the | |
1099 | value of this variable is @code{nil}, then @code{read-file-name} does | |
bfe721d1 KH |
1100 | not place any initial input in the minibuffer (unless you specify |
1101 | initial input with the @var{initial} argument). In that case, the | |
3e01fd9d RS |
1102 | default directory is still used for completion of relative file names, |
1103 | but is not displayed. | |
1104 | ||
1105 | For example: | |
1106 | ||
1107 | @example | |
1108 | @group | |
1109 | ;; @r{Here the minibuffer starts out with the default directory.} | |
1110 | (let ((insert-default-directory t)) | |
1111 | (read-file-name "The file is ")) | |
1112 | @end group | |
1113 | ||
1114 | @group | |
1115 | ---------- Buffer: Minibuffer ---------- | |
1116 | The file is ~lewis/manual/@point{} | |
1117 | ---------- Buffer: Minibuffer ---------- | |
1118 | @end group | |
1119 | ||
1120 | @group | |
1121 | ;; @r{Here the minibuffer is empty and only the prompt} | |
1122 | ;; @r{appears on its line.} | |
1123 | (let ((insert-default-directory nil)) | |
1124 | (read-file-name "The file is ")) | |
1125 | @end group | |
1126 | ||
1127 | @group | |
1128 | ---------- Buffer: Minibuffer ---------- | |
1129 | The file is @point{} | |
1130 | ---------- Buffer: Minibuffer ---------- | |
1131 | @end group | |
1132 | @end example | |
1133 | @end defopt | |
1134 | ||
1135 | @node Programmed Completion | |
1136 | @subsection Programmed Completion | |
1137 | @cindex programmed completion | |
1138 | ||
1139 | Sometimes it is not possible to create an alist or an obarray | |
1140 | containing all the intended possible completions. In such a case, you | |
1141 | can supply your own function to compute the completion of a given string. | |
1142 | This is called @dfn{programmed completion}. | |
1143 | ||
1144 | To use this feature, pass a symbol with a function definition as the | |
793da230 RS |
1145 | @var{collection} argument to @code{completing-read}. The function |
1146 | @code{completing-read} arranges to pass your completion function along | |
1147 | to @code{try-completion} and @code{all-completions}, which will then let | |
1148 | your function do all the work. | |
3e01fd9d RS |
1149 | |
1150 | The completion function should accept three arguments: | |
1151 | ||
1152 | @itemize @bullet | |
1153 | @item | |
1154 | The string to be completed. | |
1155 | ||
1156 | @item | |
1157 | The predicate function to filter possible matches, or @code{nil} if | |
1158 | none. Your function should call the predicate for each possible match, | |
1159 | and ignore the possible match if the predicate returns @code{nil}. | |
1160 | ||
1161 | @item | |
1162 | A flag specifying the type of operation. | |
1163 | @end itemize | |
1164 | ||
1165 | There are three flag values for three operations: | |
1166 | ||
1167 | @itemize @bullet | |
1168 | @item | |
1169 | @code{nil} specifies @code{try-completion}. The completion function | |
1170 | should return the completion of the specified string, or @code{t} if the | |
d595eca0 RS |
1171 | string is a unique and exact match already, or @code{nil} if the string |
1172 | matches no possibility. | |
1173 | ||
1174 | If the string is an exact match for one possibility, but also matches | |
969fe9b5 | 1175 | other longer possibilities, the function should return the string, not |
d595eca0 | 1176 | @code{t}. |
3e01fd9d RS |
1177 | |
1178 | @item | |
1179 | @code{t} specifies @code{all-completions}. The completion function | |
1180 | should return a list of all possible completions of the specified | |
1181 | string. | |
1182 | ||
1183 | @item | |
1184 | @code{lambda} specifies a test for an exact match. The completion | |
1185 | function should return @code{t} if the specified string is an exact | |
1186 | match for some possibility; @code{nil} otherwise. | |
1187 | @end itemize | |
1188 | ||
1189 | It would be consistent and clean for completion functions to allow | |
bfe721d1 | 1190 | lambda expressions (lists that are functions) as well as function |
3e01fd9d RS |
1191 | symbols as @var{collection}, but this is impossible. Lists as |
1192 | completion tables are already assigned another meaning---as alists. It | |
1193 | would be unreliable to fail to handle an alist normally because it is | |
1194 | also a possible function. So you must arrange for any function you wish | |
1195 | to use for completion to be encapsulated in a symbol. | |
1196 | ||
1197 | Emacs uses programmed completion when completing file names. | |
1198 | @xref{File Name Completion}. | |
1199 | ||
1200 | @node Yes-or-No Queries | |
1201 | @section Yes-or-No Queries | |
1202 | @cindex asking the user questions | |
1203 | @cindex querying the user | |
1204 | @cindex yes-or-no questions | |
1205 | ||
1206 | This section describes functions used to ask the user a yes-or-no | |
1207 | question. The function @code{y-or-n-p} can be answered with a single | |
1208 | character; it is useful for questions where an inadvertent wrong answer | |
1209 | will not have serious consequences. @code{yes-or-no-p} is suitable for | |
1210 | more momentous questions, since it requires three or four characters to | |
1211 | answer. | |
1212 | ||
3e099569 RS |
1213 | If either of these functions is called in a command that was invoked |
1214 | using the mouse---more precisely, if @code{last-nonmenu-event} | |
1215 | (@pxref{Command Loop Info}) is either @code{nil} or a list---then it | |
1216 | uses a dialog box or pop-up menu to ask the question. Otherwise, it | |
1217 | uses keyboard input. You can force use of the mouse or use of keyboard | |
1218 | input by binding @code{last-nonmenu-event} to a suitable value around | |
1219 | the call. | |
1220 | ||
3e01fd9d RS |
1221 | Strictly speaking, @code{yes-or-no-p} uses the minibuffer and |
1222 | @code{y-or-n-p} does not; but it seems best to describe them together. | |
1223 | ||
1224 | @defun y-or-n-p prompt | |
793da230 | 1225 | This function asks the user a question, expecting input in the echo |
3e01fd9d RS |
1226 | area. It returns @code{t} if the user types @kbd{y}, @code{nil} if the |
1227 | user types @kbd{n}. This function also accepts @key{SPC} to mean yes | |
1228 | and @key{DEL} to mean no. It accepts @kbd{C-]} to mean ``quit'', like | |
1229 | @kbd{C-g}, because the question might look like a minibuffer and for | |
1230 | that reason the user might try to use @kbd{C-]} to get out. The answer | |
1231 | is a single character, with no @key{RET} needed to terminate it. Upper | |
1232 | and lower case are equivalent. | |
1233 | ||
793da230 | 1234 | ``Asking the question'' means printing @var{prompt} in the echo area, |
3e01fd9d RS |
1235 | followed by the string @w{@samp{(y or n) }}. If the input is not one of |
1236 | the expected answers (@kbd{y}, @kbd{n}, @kbd{@key{SPC}}, | |
1237 | @kbd{@key{DEL}}, or something that quits), the function responds | |
1238 | @samp{Please answer y or n.}, and repeats the request. | |
1239 | ||
793da230 | 1240 | This function does not actually use the minibuffer, since it does not |
3e01fd9d RS |
1241 | allow editing of the answer. It actually uses the echo area (@pxref{The |
1242 | Echo Area}), which uses the same screen space as the minibuffer. The | |
1243 | cursor moves to the echo area while the question is being asked. | |
1244 | ||
793da230 | 1245 | The answers and their meanings, even @samp{y} and @samp{n}, are not |
3e01fd9d RS |
1246 | hardwired. The keymap @code{query-replace-map} specifies them. |
1247 | @xref{Search and Replace}. | |
1248 | ||
793da230 | 1249 | In the following example, the user first types @kbd{q}, which is |
3e01fd9d RS |
1250 | invalid. At the next prompt the user types @kbd{y}. |
1251 | ||
1252 | @smallexample | |
1253 | @group | |
1254 | (y-or-n-p "Do you need a lift? ") | |
1255 | ||
793da230 | 1256 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
1257 | ;; @r{the following prompt appears in the echo area:} |
1258 | @end group | |
1259 | ||
1260 | @group | |
1261 | ---------- Echo area ---------- | |
1262 | Do you need a lift? (y or n) | |
1263 | ---------- Echo area ---------- | |
1264 | @end group | |
1265 | ||
1266 | ;; @r{If the user then types @kbd{q}, the following appears:} | |
1267 | ||
1268 | @group | |
1269 | ---------- Echo area ---------- | |
1270 | Please answer y or n. Do you need a lift? (y or n) | |
1271 | ---------- Echo area ---------- | |
1272 | @end group | |
1273 | ||
1274 | ;; @r{When the user types a valid answer,} | |
1275 | ;; @r{it is displayed after the question:} | |
1276 | ||
1277 | @group | |
1278 | ---------- Echo area ---------- | |
1279 | Do you need a lift? (y or n) y | |
1280 | ---------- Echo area ---------- | |
1281 | @end group | |
1282 | @end smallexample | |
1283 | ||
1284 | @noindent | |
1285 | We show successive lines of echo area messages, but only one actually | |
1286 | appears on the screen at a time. | |
1287 | @end defun | |
1288 | ||
48a58303 RS |
1289 | @defun y-or-n-p-with-timeout prompt seconds default-value |
1290 | Like @code{y-or-n-p}, except that if the user fails to answer within | |
1291 | @var{seconds} seconds, this function stops waiting and returns | |
1292 | @var{default-value}. It works by setting up a timer; see @ref{Timers}. | |
1293 | The argument @var{seconds} may be an integer or a floating point number. | |
1294 | @end defun | |
1295 | ||
3e01fd9d | 1296 | @defun yes-or-no-p prompt |
793da230 RS |
1297 | This function asks the user a question, expecting input in the |
1298 | minibuffer. It returns @code{t} if the user enters @samp{yes}, | |
1299 | @code{nil} if the user types @samp{no}. The user must type @key{RET} to | |
1300 | finalize the response. Upper and lower case are equivalent. | |
3e01fd9d | 1301 | |
793da230 | 1302 | @code{yes-or-no-p} starts by displaying @var{prompt} in the echo area, |
3e01fd9d RS |
1303 | followed by @w{@samp{(yes or no) }}. The user must type one of the |
1304 | expected responses; otherwise, the function responds @samp{Please answer | |
1305 | yes or no.}, waits about two seconds and repeats the request. | |
1306 | ||
793da230 | 1307 | @code{yes-or-no-p} requires more work from the user than |
3e01fd9d RS |
1308 | @code{y-or-n-p} and is appropriate for more crucial decisions. |
1309 | ||
3e01fd9d RS |
1310 | Here is an example: |
1311 | ||
1312 | @smallexample | |
1313 | @group | |
1314 | (yes-or-no-p "Do you really want to remove everything? ") | |
1315 | ||
793da230 | 1316 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
1317 | ;; @r{the following prompt appears,} |
1318 | ;; @r{with an empty minibuffer:} | |
1319 | @end group | |
1320 | ||
1321 | @group | |
1322 | ---------- Buffer: minibuffer ---------- | |
1323 | Do you really want to remove everything? (yes or no) | |
1324 | ---------- Buffer: minibuffer ---------- | |
1325 | @end group | |
1326 | @end smallexample | |
1327 | ||
1328 | @noindent | |
1329 | If the user first types @kbd{y @key{RET}}, which is invalid because this | |
1330 | function demands the entire word @samp{yes}, it responds by displaying | |
1331 | these prompts, with a brief pause between them: | |
1332 | ||
1333 | @smallexample | |
1334 | @group | |
1335 | ---------- Buffer: minibuffer ---------- | |
1336 | Please answer yes or no. | |
1337 | Do you really want to remove everything? (yes or no) | |
1338 | ---------- Buffer: minibuffer ---------- | |
1339 | @end group | |
1340 | @end smallexample | |
1341 | @end defun | |
1342 | ||
1343 | @node Multiple Queries | |
1344 | @section Asking Multiple Y-or-N Questions | |
1345 | ||
793da230 RS |
1346 | When you have a series of similar questions to ask, such as ``Do you |
1347 | want to save this buffer'' for each buffer in turn, you should use | |
1348 | @code{map-y-or-n-p} to ask the collection of questions, rather than | |
1349 | asking each question individually. This gives the user certain | |
1350 | convenient facilities such as the ability to answer the whole series at | |
1351 | once. | |
1352 | ||
3e01fd9d | 1353 | @defun map-y-or-n-p prompter actor list &optional help action-alist |
f9f59935 RS |
1354 | This function asks the user a series of questions, reading a |
1355 | single-character answer in the echo area for each one. | |
3e01fd9d RS |
1356 | |
1357 | The value of @var{list} specifies the objects to ask questions about. | |
1358 | It should be either a list of objects or a generator function. If it is | |
1359 | a function, it should expect no arguments, and should return either the | |
1360 | next object to ask about, or @code{nil} meaning stop asking questions. | |
1361 | ||
1362 | The argument @var{prompter} specifies how to ask each question. If | |
1363 | @var{prompter} is a string, the question text is computed like this: | |
1364 | ||
1365 | @example | |
1366 | (format @var{prompter} @var{object}) | |
1367 | @end example | |
1368 | ||
1369 | @noindent | |
1370 | where @var{object} is the next object to ask about (as obtained from | |
1371 | @var{list}). | |
1372 | ||
1373 | If not a string, @var{prompter} should be a function of one argument | |
63ff95ee MW |
1374 | (the next object to ask about) and should return the question text. If |
1375 | the value is a string, that is the question to ask the user. The | |
1376 | function can also return @code{t} meaning do act on this object (and | |
1377 | don't ask the user), or @code{nil} meaning ignore this object (and don't | |
1378 | ask the user). | |
3e01fd9d RS |
1379 | |
1380 | The argument @var{actor} says how to act on the answers that the user | |
1381 | gives. It should be a function of one argument, and it is called with | |
1382 | each object that the user says yes for. Its argument is always an | |
1383 | object obtained from @var{list}. | |
1384 | ||
1385 | If the argument @var{help} is given, it should be a list of this form: | |
1386 | ||
1387 | @example | |
1388 | (@var{singular} @var{plural} @var{action}) | |
1389 | @end example | |
1390 | ||
1391 | @noindent | |
1392 | where @var{singular} is a string containing a singular noun that | |
1393 | describes the objects conceptually being acted on, @var{plural} is the | |
1394 | corresponding plural noun, and @var{action} is a transitive verb | |
1395 | describing what @var{actor} does. | |
1396 | ||
1397 | If you don't specify @var{help}, the default is @code{("object" | |
1398 | "objects" "act on")}. | |
1399 | ||
1400 | Each time a question is asked, the user may enter @kbd{y}, @kbd{Y}, or | |
1401 | @key{SPC} to act on that object; @kbd{n}, @kbd{N}, or @key{DEL} to skip | |
1402 | that object; @kbd{!} to act on all following objects; @key{ESC} or | |
1403 | @kbd{q} to exit (skip all following objects); @kbd{.} (period) to act on | |
1404 | the current object and then exit; or @kbd{C-h} to get help. These are | |
1405 | the same answers that @code{query-replace} accepts. The keymap | |
1406 | @code{query-replace-map} defines their meaning for @code{map-y-or-n-p} | |
1407 | as well as for @code{query-replace}; see @ref{Search and Replace}. | |
1408 | ||
1409 | You can use @var{action-alist} to specify additional possible answers | |
1410 | and what they mean. It is an alist of elements of the form | |
1411 | @code{(@var{char} @var{function} @var{help})}, each of which defines one | |
1412 | additional answer. In this element, @var{char} is a character (the | |
1413 | answer); @var{function} is a function of one argument (an object from | |
1414 | @var{list}); @var{help} is a string. | |
1415 | ||
1416 | When the user responds with @var{char}, @code{map-y-or-n-p} calls | |
1417 | @var{function}. If it returns non-@code{nil}, the object is considered | |
1418 | ``acted upon'', and @code{map-y-or-n-p} advances to the next object in | |
1419 | @var{list}. If it returns @code{nil}, the prompt is repeated for the | |
1420 | same object. | |
1421 | ||
3e099569 RS |
1422 | If @code{map-y-or-n-p} is called in a command that was invoked using the |
1423 | mouse---more precisely, if @code{last-nonmenu-event} (@pxref{Command | |
1424 | Loop Info}) is either @code{nil} or a list---then it uses a dialog box | |
1425 | or pop-up menu to ask the question. In this case, it does not use | |
1426 | keyboard input or the echo area. You can force use of the mouse or use | |
1427 | of keyboard input by binding @code{last-nonmenu-event} to a suitable | |
1428 | value around the call. | |
1429 | ||
3e01fd9d RS |
1430 | The return value of @code{map-y-or-n-p} is the number of objects acted on. |
1431 | @end defun | |
1432 | ||
e75ecfec KH |
1433 | @node Reading a Password |
1434 | @section Reading a Password | |
1435 | @cindex passwords, reading | |
1436 | ||
1437 | To read a password to pass to another program, you can use the | |
1438 | function @code{read-passwd}. | |
1439 | ||
1440 | @tindex read-passwd | |
1441 | @defun read-passwd prompt &optional confirm default | |
1442 | This function reads a password, prompting with @var{prompt}. It does | |
1443 | not echo the password as the user types it; instead, it echoes @samp{.} | |
1444 | for each character in the password. | |
1445 | ||
1446 | The optional argument @var{confirm}, if non-@code{nil}, says to read the | |
1447 | password twice and insist it must be the same both times. If it isn't | |
1448 | the same, the user has to type it over and over until the last two | |
1449 | times match. | |
1450 | ||
1451 | The optional argument @var{default} specifies the default password to | |
1452 | return if the user enters empty input. If @var{default} is @code{nil}, | |
1453 | then @code{read-passwd} returns the null string in that case. | |
1454 | @end defun | |
1455 | ||
3e01fd9d | 1456 | @node Minibuffer Misc |
3e01fd9d RS |
1457 | @section Minibuffer Miscellany |
1458 | ||
1459 | This section describes some basic functions and variables related to | |
1460 | minibuffers. | |
1461 | ||
1462 | @deffn Command exit-minibuffer | |
1463 | This command exits the active minibuffer. It is normally bound to | |
1464 | keys in minibuffer local keymaps. | |
1465 | @end deffn | |
1466 | ||
1467 | @deffn Command self-insert-and-exit | |
1468 | This command exits the active minibuffer after inserting the last | |
1469 | character typed on the keyboard (found in @code{last-command-char}; | |
1470 | @pxref{Command Loop Info}). | |
1471 | @end deffn | |
1472 | ||
1473 | @deffn Command previous-history-element n | |
1474 | This command replaces the minibuffer contents with the value of the | |
1475 | @var{n}th previous (older) history element. | |
1476 | @end deffn | |
1477 | ||
1478 | @deffn Command next-history-element n | |
1479 | This command replaces the minibuffer contents with the value of the | |
1480 | @var{n}th more recent history element. | |
1481 | @end deffn | |
1482 | ||
1483 | @deffn Command previous-matching-history-element pattern | |
1484 | This command replaces the minibuffer contents with the value of the | |
793da230 RS |
1485 | previous (older) history element that matches @var{pattern} (a regular |
1486 | expression). | |
3e01fd9d RS |
1487 | @end deffn |
1488 | ||
1489 | @deffn Command next-matching-history-element pattern | |
793da230 RS |
1490 | This command replaces the minibuffer contents with the value of the next |
1491 | (newer) history element that matches @var{pattern} (a regular | |
1492 | expression). | |
3e01fd9d RS |
1493 | @end deffn |
1494 | ||
bfe721d1 KH |
1495 | @defun minibuffer-prompt |
1496 | This function returns the prompt string of the currently active | |
1497 | minibuffer. If no minibuffer is active, it returns @code{nil}. | |
1498 | @end defun | |
1499 | ||
8241495d RS |
1500 | @tindex minubuffer-prompt-end |
1501 | @defun minubuffer-prompt-end | |
1502 | This function, available starting in Emacs 21, returns the current | |
1503 | position of the end of the minibuffer prompt, if a minibuffer is | |
1504 | current. Otherwise, it returns zero. | |
1505 | @end defun | |
1506 | ||
1507 | @defun minubuffer-prompt-width | |
1508 | This function returns the current display-width of the minibuffer | |
1509 | prompt, if a minibuffer is current. Otherwise, it returns zero. | |
bfe721d1 KH |
1510 | @end defun |
1511 | ||
3e01fd9d RS |
1512 | @defvar minibuffer-setup-hook |
1513 | This is a normal hook that is run whenever the minibuffer is entered. | |
793da230 RS |
1514 | @xref{Hooks}. |
1515 | @end defvar | |
1516 | ||
612b4d5c | 1517 | @defvar minibuffer-exit-hook |
793da230 RS |
1518 | This is a normal hook that is run whenever the minibuffer is exited. |
1519 | @xref{Hooks}. | |
3e01fd9d RS |
1520 | @end defvar |
1521 | ||
1522 | @defvar minibuffer-help-form | |
1523 | The current value of this variable is used to rebind @code{help-form} | |
1524 | locally inside the minibuffer (@pxref{Help Functions}). | |
1525 | @end defvar | |
1526 | ||
22697dac KH |
1527 | @defun active-minibuffer-window |
1528 | This function returns the currently active minibuffer window, or | |
1529 | @code{nil} if none is currently active. | |
1530 | @end defun | |
1531 | ||
3e01fd9d | 1532 | @defun minibuffer-window &optional frame |
22697dac KH |
1533 | This function returns the minibuffer window used for frame @var{frame}. |
1534 | If @var{frame} is @code{nil}, that stands for the current frame. Note | |
1535 | that the minibuffer window used by a frame need not be part of that | |
1536 | frame---a frame that has no minibuffer of its own necessarily uses some | |
1537 | other frame's minibuffer window. | |
3e01fd9d RS |
1538 | @end defun |
1539 | ||
1540 | @c Emacs 19 feature | |
1541 | @defun window-minibuffer-p window | |
1542 | This function returns non-@code{nil} if @var{window} is a minibuffer window. | |
1543 | @end defun | |
1544 | ||
1545 | It is not correct to determine whether a given window is a minibuffer by | |
1546 | comparing it with the result of @code{(minibuffer-window)}, because | |
1547 | there can be more than one minibuffer window if there is more than one | |
1548 | frame. | |
1549 | ||
1550 | @defun minibuffer-window-active-p window | |
1551 | This function returns non-@code{nil} if @var{window}, assumed to be | |
1552 | a minibuffer window, is currently active. | |
1553 | @end defun | |
1554 | ||
1555 | @defvar minibuffer-scroll-window | |
1556 | If the value of this variable is non-@code{nil}, it should be a window | |
1557 | object. When the function @code{scroll-other-window} is called in the | |
1558 | minibuffer, it scrolls this window. | |
1559 | @end defvar | |
1560 | ||
1561 | Finally, some functions and variables deal with recursive minibuffers | |
1562 | (@pxref{Recursive Editing}): | |
1563 | ||
1564 | @defun minibuffer-depth | |
1565 | This function returns the current depth of activations of the | |
1566 | minibuffer, a nonnegative integer. If no minibuffers are active, it | |
1567 | returns zero. | |
1568 | @end defun | |
1569 | ||
1570 | @defopt enable-recursive-minibuffers | |
1571 | If this variable is non-@code{nil}, you can invoke commands (such as | |
969fe9b5 RS |
1572 | @code{find-file}) that use minibuffers even while the minibuffer window |
1573 | is active. Such invocation produces a recursive editing level for a new | |
3e01fd9d RS |
1574 | minibuffer. The outer-level minibuffer is invisible while you are |
1575 | editing the inner one. | |
1576 | ||
969fe9b5 RS |
1577 | If this variable is @code{nil}, you cannot invoke minibuffer |
1578 | commands when the minibuffer window is active, not even if you switch to | |
1579 | another window to do it. | |
3e01fd9d RS |
1580 | @end defopt |
1581 | ||
1582 | @c Emacs 19 feature | |
1583 | If a command name has a property @code{enable-recursive-minibuffers} | |
793da230 | 1584 | that is non-@code{nil}, then the command can use the minibuffer to read |
3e01fd9d | 1585 | arguments even if it is invoked from the minibuffer. The minibuffer |
bfe721d1 KH |
1586 | command @code{next-matching-history-element} (normally @kbd{M-s} in the |
1587 | minibuffer) uses this feature. |