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1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
b3b044f2 | 3 | @c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2001 |
177c0ea7 | 4 | @c Free Software Foundation, Inc. |
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5 | @c See the file elisp.texi for copying conditions. |
6 | @setfilename ../info/minibuf | |
3e099569 | 7 | @node Minibuffers, Command Loop, Read and Print, Top |
3e01fd9d RS |
8 | @chapter Minibuffers |
9 | @cindex arguments, reading | |
10 | @cindex complex arguments | |
11 | @cindex minibuffer | |
12 | ||
13 | A @dfn{minibuffer} is a special buffer that Emacs commands use to read | |
14 | arguments more complicated than the single numeric prefix argument. | |
15 | These arguments include file names, buffer names, and command names (as | |
16 | in @kbd{M-x}). The minibuffer is displayed on the bottom line of the | |
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17 | frame, in the same place as the echo area, but only while it is in use |
18 | for reading an argument. | |
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19 | |
20 | @menu | |
21 | * Intro to Minibuffers:: Basic information about minibuffers. | |
22 | * Text from Minibuffer:: How to read a straight text string. | |
23 | * Object from Minibuffer:: How to read a Lisp object or expression. | |
24 | * Minibuffer History:: Recording previous minibuffer inputs | |
25 | so the user can reuse them. | |
26 | * Completion:: How to invoke and customize completion. | |
27 | * Yes-or-No Queries:: Asking a question with a simple answer. | |
28 | * Multiple Queries:: Asking a series of similar questions. | |
e75ecfec | 29 | * Reading a Password:: Reading a password from the terminal. |
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30 | * Minibuffer Misc:: Various customization hooks and variables. |
31 | @end menu | |
32 | ||
33 | @node Intro to Minibuffers | |
34 | @section Introduction to Minibuffers | |
35 | ||
36 | In most ways, a minibuffer is a normal Emacs buffer. Most operations | |
37 | @emph{within} a buffer, such as editing commands, work normally in a | |
38 | minibuffer. However, many operations for managing buffers do not apply | |
39 | to minibuffers. The name of a minibuffer always has the form @w{@samp{ | |
56bd69df | 40 | *Minibuf-@var{number}*}}, and it cannot be changed. Minibuffers are |
3e01fd9d | 41 | displayed only in special windows used only for minibuffers; these |
1911e6e5 | 42 | windows always appear at the bottom of a frame. (Sometimes frames have |
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43 | no minibuffer window, and sometimes a special kind of frame contains |
44 | nothing but a minibuffer window; see @ref{Minibuffers and Frames}.) | |
45 | ||
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46 | The text in the minibuffer always starts with the @dfn{prompt string}, |
47 | the text that was specified by the program that is using the minibuffer | |
48 | to tell the user what sort of input to type. This text is marked | |
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49 | read-only so you won't accidentally delete or change it. It is also |
50 | marked as a field (@pxref{Fields}), so that certain motion functions, | |
51 | including @code{beginning-of-line}, @code{forward-word}, | |
52 | @code{forward-sentence}, and @code{forward-paragraph}, stop at the | |
53 | boundary between the prompt and the actual text. (In older Emacs | |
54 | versions, the prompt was displayed using a special mechanism and was not | |
55 | part of the buffer contents.) | |
56 | ||
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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 | ||
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97 | When Emacs is running in batch mode, any request to read from the |
98 | minibuffer actually reads a line from the standard input descriptor that | |
99 | was supplied when Emacs was started. | |
100 | ||
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101 | @node Text from Minibuffer |
102 | @section Reading Text Strings with the Minibuffer | |
103 | ||
793da230 RS |
104 | Most often, the minibuffer is used to read text as a string. It can |
105 | also be used to read a Lisp object in textual form. The most basic | |
106 | primitive for minibuffer input is @code{read-from-minibuffer}; it can do | |
107 | either one. | |
3e01fd9d | 108 | |
bfe721d1 KH |
109 | In most cases, you should not call minibuffer input functions in the |
110 | middle of a Lisp function. Instead, do all minibuffer input as part of | |
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111 | reading the arguments for a command, in the @code{interactive} |
112 | specification. @xref{Defining Commands}. | |
bfe721d1 | 113 | |
f9f59935 | 114 | @defun read-from-minibuffer prompt-string &optional initial-contents keymap read hist default inherit-input-method |
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115 | This function is the most general way to get input through the |
116 | minibuffer. By default, it accepts arbitrary text and returns it as a | |
117 | string; however, if @var{read} is non-@code{nil}, then it uses | |
118 | @code{read} to convert the text into a Lisp object (@pxref{Input | |
119 | Functions}). | |
120 | ||
969fe9b5 | 121 | The first thing this function does is to activate a minibuffer and |
3e01fd9d | 122 | display it with @var{prompt-string} as the prompt. This value must be a |
969fe9b5 | 123 | string. Then the user can edit text in the minibuffer. |
3e01fd9d | 124 | |
969fe9b5 RS |
125 | When the user types a command to exit the minibuffer, |
126 | @code{read-from-minibuffer} constructs the return value from the text in | |
127 | the minibuffer. Normally it returns a string containing that text. | |
128 | However, if @var{read} is non-@code{nil}, @code{read-from-minibuffer} | |
129 | reads the text and returns the resulting Lisp object, unevaluated. | |
130 | (@xref{Input Functions}, for information about reading.) | |
f9f59935 | 131 | |
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132 | The argument @var{default} specifies a default value to make available |
133 | through the history commands. It should be a string, or @code{nil}. If | |
134 | @var{read} is non-@code{nil}, then @var{default} is also used as the | |
135 | input to @code{read}, if the user enters empty input. However, in the | |
a9f0a989 | 136 | usual case (where @var{read} is @code{nil}), @code{read-from-minibuffer} |
969fe9b5 RS |
137 | does not return @var{default} when the user enters empty input; it |
138 | returns an empty string, @code{""}. In this respect, it is different | |
139 | from all the other minibuffer input functions in this chapter. | |
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140 | |
141 | If @var{keymap} is non-@code{nil}, that keymap is the local keymap to | |
142 | use in the minibuffer. If @var{keymap} is omitted or @code{nil}, the | |
143 | value of @code{minibuffer-local-map} is used as the keymap. Specifying | |
144 | a keymap is the most important way to customize the minibuffer for | |
145 | various applications such as completion. | |
146 | ||
147 | The argument @var{hist} specifies which history list variable to use | |
148 | for saving the input and for history commands used in the minibuffer. | |
149 | It defaults to @code{minibuffer-history}. @xref{Minibuffer History}. | |
150 | ||
f9f59935 RS |
151 | If the variable @code{minibuffer-allow-text-properties} is |
152 | non-@code{nil}, then the string which is returned includes whatever text | |
153 | properties were present in the minibuffer. Otherwise all the text | |
154 | properties are stripped when the value is returned. | |
155 | ||
f9f59935 | 156 | If the argument @var{inherit-input-method} is non-@code{nil}, then the |
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157 | minibuffer inherits the current input method (@pxref{Input Methods}) and |
158 | the setting of @code{enable-multibyte-characters} (@pxref{Text | |
159 | Representations}) from whichever buffer was current before entering the | |
160 | minibuffer. | |
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161 | |
162 | If @var{initial-contents} is a string, @code{read-from-minibuffer} | |
163 | inserts it into the minibuffer, leaving point at the end, before the | |
164 | user starts to edit the text. The minibuffer appears with this text as | |
165 | its initial contents. | |
166 | ||
167 | Alternatively, @var{initial-contents} can be a cons cell of the form | |
168 | @code{(@var{string} . @var{position})}. This means to insert | |
169 | @var{string} in the minibuffer but put point @var{position} characters | |
170 | from the beginning, rather than at the end. | |
171 | ||
172 | @strong{Usage note:} The @var{initial-contents} argument and the | |
173 | @var{default} argument are two alternative features for more or less the | |
174 | same job. It does not make sense to use both features in a single call | |
175 | to @code{read-from-minibuffer}. In general, we recommend using | |
176 | @var{default}, since this permits the user to insert the default value | |
177 | when it is wanted, but does not burden the user with deleting it from | |
178 | the minibuffer on other occasions. | |
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179 | @end defun |
180 | ||
f9f59935 | 181 | @defun read-string prompt &optional initial history default inherit-input-method |
3e01fd9d RS |
182 | This function reads a string from the minibuffer and returns it. The |
183 | arguments @var{prompt} and @var{initial} are used as in | |
184 | @code{read-from-minibuffer}. The keymap used is | |
185 | @code{minibuffer-local-map}. | |
186 | ||
f9f59935 RS |
187 | The optional argument @var{history}, if non-nil, specifies a history |
188 | list and optionally the initial position in the list. The optional | |
189 | argument @var{default} specifies a default value to return if the user | |
190 | enters null input; it should be a string. The optional argument | |
191 | @var{inherit-input-method} specifies whether to inherit the current | |
192 | buffer's input method. | |
193 | ||
194 | This function is a simplified interface to the | |
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195 | @code{read-from-minibuffer} function: |
196 | ||
197 | @smallexample | |
198 | @group | |
f9f59935 | 199 | (read-string @var{prompt} @var{initial} @var{history} @var{default} @var{inherit}) |
3e01fd9d | 200 | @equiv{} |
969fe9b5 RS |
201 | (let ((value |
202 | (read-from-minibuffer @var{prompt} @var{initial} nil nil | |
203 | @var{history} @var{default} @var{inherit}))) | |
204 | (if (equal value "") | |
205 | @var{default} | |
206 | value)) | |
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207 | @end group |
208 | @end smallexample | |
209 | @end defun | |
210 | ||
f9f59935 | 211 | @defvar minibuffer-allow-text-properties |
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212 | If this variable is @code{nil}, then @code{read-from-minibuffer} strips |
213 | all text properties from the minibuffer input before returning it. | |
f9f59935 RS |
214 | Since all minibuffer input uses @code{read-from-minibuffer}, this |
215 | variable applies to all minibuffer input. | |
1911e6e5 RS |
216 | |
217 | Note that the completion functions discard text properties unconditionally, | |
218 | regardless of the value of this variable. | |
f9f59935 RS |
219 | @end defvar |
220 | ||
3e01fd9d RS |
221 | @defvar minibuffer-local-map |
222 | This is the default local keymap for reading from the minibuffer. By | |
223 | default, it makes the following bindings: | |
224 | ||
225 | @table @asis | |
969fe9b5 | 226 | @item @kbd{C-j} |
3e01fd9d RS |
227 | @code{exit-minibuffer} |
228 | ||
229 | @item @key{RET} | |
230 | @code{exit-minibuffer} | |
231 | ||
232 | @item @kbd{C-g} | |
233 | @code{abort-recursive-edit} | |
234 | ||
235 | @item @kbd{M-n} | |
236 | @code{next-history-element} | |
237 | ||
238 | @item @kbd{M-p} | |
239 | @code{previous-history-element} | |
240 | ||
241 | @item @kbd{M-r} | |
242 | @code{next-matching-history-element} | |
243 | ||
244 | @item @kbd{M-s} | |
245 | @code{previous-matching-history-element} | |
246 | @end table | |
247 | @end defvar | |
248 | ||
249 | @c In version 18, initial is required | |
250 | @c Emacs 19 feature | |
f9f59935 | 251 | @defun read-no-blanks-input prompt &optional initial inherit-input-method |
3e01fd9d RS |
252 | This function reads a string from the minibuffer, but does not allow |
253 | whitespace characters as part of the input: instead, those characters | |
f9f59935 RS |
254 | terminate the input. The arguments @var{prompt}, @var{initial}, and |
255 | @var{inherit-input-method} are used as in @code{read-from-minibuffer}. | |
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256 | |
257 | This is a simplified interface to the @code{read-from-minibuffer} | |
258 | function, and passes the value of the @code{minibuffer-local-ns-map} | |
259 | keymap as the @var{keymap} argument for that function. Since the keymap | |
260 | @code{minibuffer-local-ns-map} does not rebind @kbd{C-q}, it @emph{is} | |
261 | possible to put a space into the string, by quoting it. | |
262 | ||
263 | @smallexample | |
264 | @group | |
265 | (read-no-blanks-input @var{prompt} @var{initial}) | |
266 | @equiv{} | |
267 | (read-from-minibuffer @var{prompt} @var{initial} minibuffer-local-ns-map) | |
268 | @end group | |
269 | @end smallexample | |
270 | @end defun | |
271 | ||
272 | @defvar minibuffer-local-ns-map | |
273 | This built-in variable is the keymap used as the minibuffer local keymap | |
274 | in the function @code{read-no-blanks-input}. By default, it makes the | |
bfe721d1 | 275 | following bindings, in addition to those of @code{minibuffer-local-map}: |
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276 | |
277 | @table @asis | |
3e01fd9d RS |
278 | @item @key{SPC} |
279 | @cindex @key{SPC} in minibuffer | |
280 | @code{exit-minibuffer} | |
281 | ||
282 | @item @key{TAB} | |
283 | @cindex @key{TAB} in minibuffer | |
284 | @code{exit-minibuffer} | |
285 | ||
3e01fd9d RS |
286 | @item @kbd{?} |
287 | @cindex @kbd{?} in minibuffer | |
288 | @code{self-insert-and-exit} | |
3e01fd9d RS |
289 | @end table |
290 | @end defvar | |
291 | ||
292 | @node Object from Minibuffer | |
293 | @section Reading Lisp Objects with the Minibuffer | |
294 | ||
295 | This section describes functions for reading Lisp objects with the | |
296 | minibuffer. | |
297 | ||
298 | @defun read-minibuffer prompt &optional initial | |
f9f59935 | 299 | This function reads a Lisp object using the minibuffer, and returns it |
3e01fd9d | 300 | without evaluating it. The arguments @var{prompt} and @var{initial} are |
793da230 | 301 | used as in @code{read-from-minibuffer}. |
3e01fd9d | 302 | |
793da230 | 303 | This is a simplified interface to the |
3e01fd9d RS |
304 | @code{read-from-minibuffer} function: |
305 | ||
306 | @smallexample | |
307 | @group | |
308 | (read-minibuffer @var{prompt} @var{initial}) | |
309 | @equiv{} | |
310 | (read-from-minibuffer @var{prompt} @var{initial} nil t) | |
311 | @end group | |
312 | @end smallexample | |
313 | ||
314 | Here is an example in which we supply the string @code{"(testing)"} as | |
315 | initial input: | |
316 | ||
317 | @smallexample | |
318 | @group | |
319 | (read-minibuffer | |
320 | "Enter an expression: " (format "%s" '(testing))) | |
321 | ||
322 | ;; @r{Here is how the minibuffer is displayed:} | |
323 | @end group | |
324 | ||
325 | @group | |
326 | ---------- Buffer: Minibuffer ---------- | |
327 | Enter an expression: (testing)@point{} | |
328 | ---------- Buffer: Minibuffer ---------- | |
329 | @end group | |
330 | @end smallexample | |
331 | ||
332 | @noindent | |
333 | The user can type @key{RET} immediately to use the initial input as a | |
334 | default, or can edit the input. | |
335 | @end defun | |
336 | ||
337 | @defun eval-minibuffer prompt &optional initial | |
f9f59935 RS |
338 | This function reads a Lisp expression using the minibuffer, evaluates |
339 | it, then returns the result. The arguments @var{prompt} and | |
340 | @var{initial} are used as in @code{read-from-minibuffer}. | |
3e01fd9d | 341 | |
793da230 | 342 | This function simply evaluates the result of a call to |
3e01fd9d RS |
343 | @code{read-minibuffer}: |
344 | ||
345 | @smallexample | |
346 | @group | |
347 | (eval-minibuffer @var{prompt} @var{initial}) | |
348 | @equiv{} | |
349 | (eval (read-minibuffer @var{prompt} @var{initial})) | |
350 | @end group | |
351 | @end smallexample | |
352 | @end defun | |
353 | ||
354 | @defun edit-and-eval-command prompt form | |
793da230 | 355 | This function reads a Lisp expression in the minibuffer, and then |
3e01fd9d RS |
356 | evaluates it. The difference between this command and |
357 | @code{eval-minibuffer} is that here the initial @var{form} is not | |
358 | optional and it is treated as a Lisp object to be converted to printed | |
359 | representation rather than as a string of text. It is printed with | |
360 | @code{prin1}, so if it is a string, double-quote characters (@samp{"}) | |
361 | appear in the initial text. @xref{Output Functions}. | |
362 | ||
793da230 | 363 | The first thing @code{edit-and-eval-command} does is to activate the |
3e01fd9d | 364 | minibuffer with @var{prompt} as the prompt. Then it inserts the printed |
f9f59935 | 365 | representation of @var{form} in the minibuffer, and lets the user edit it. |
3e01fd9d RS |
366 | When the user exits the minibuffer, the edited text is read with |
367 | @code{read} and then evaluated. The resulting value becomes the value | |
368 | of @code{edit-and-eval-command}. | |
369 | ||
793da230 | 370 | In the following example, we offer the user an expression with initial |
3e01fd9d RS |
371 | text which is a valid form already: |
372 | ||
373 | @smallexample | |
374 | @group | |
375 | (edit-and-eval-command "Please edit: " '(forward-word 1)) | |
376 | ||
177c0ea7 | 377 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
378 | ;; @r{the following appears in the minibuffer:} |
379 | @end group | |
380 | ||
381 | @group | |
382 | ---------- Buffer: Minibuffer ---------- | |
383 | Please edit: (forward-word 1)@point{} | |
384 | ---------- Buffer: Minibuffer ---------- | |
385 | @end group | |
386 | @end smallexample | |
387 | ||
388 | @noindent | |
389 | Typing @key{RET} right away would exit the minibuffer and evaluate the | |
390 | expression, thus moving point forward one word. | |
391 | @code{edit-and-eval-command} returns @code{nil} in this example. | |
392 | @end defun | |
393 | ||
394 | @node Minibuffer History | |
395 | @section Minibuffer History | |
396 | @cindex minibuffer history | |
397 | @cindex history list | |
398 | ||
969fe9b5 | 399 | A @dfn{minibuffer history list} records previous minibuffer inputs so |
793da230 RS |
400 | the user can reuse them conveniently. A history list is actually a |
401 | symbol, not a list; it is a variable whose value is a list of strings | |
402 | (previous inputs), most recent first. | |
3e01fd9d | 403 | |
969fe9b5 | 404 | There are many separate history lists, used for different kinds of |
3e01fd9d RS |
405 | inputs. It's the Lisp programmer's job to specify the right history |
406 | list for each use of the minibuffer. | |
407 | ||
969fe9b5 | 408 | The basic minibuffer input functions @code{read-from-minibuffer} and |
3e01fd9d RS |
409 | @code{completing-read} both accept an optional argument named @var{hist} |
410 | which is how you specify the history list. Here are the possible | |
411 | values: | |
412 | ||
413 | @table @asis | |
414 | @item @var{variable} | |
415 | Use @var{variable} (a symbol) as the history list. | |
416 | ||
417 | @item (@var{variable} . @var{startpos}) | |
418 | Use @var{variable} (a symbol) as the history list, and assume that the | |
419 | initial history position is @var{startpos} (an integer, counting from | |
420 | zero which specifies the most recent element of the history). | |
421 | ||
422 | If you specify @var{startpos}, then you should also specify that element | |
423 | of the history as the initial minibuffer contents, for consistency. | |
424 | @end table | |
425 | ||
969fe9b5 | 426 | If you don't specify @var{hist}, then the default history list |
3e01fd9d RS |
427 | @code{minibuffer-history} is used. For other standard history lists, |
428 | see below. You can also create your own history list variable; just | |
429 | initialize it to @code{nil} before the first use. | |
430 | ||
969fe9b5 | 431 | Both @code{read-from-minibuffer} and @code{completing-read} add new |
3e01fd9d RS |
432 | elements to the history list automatically, and provide commands to |
433 | allow the user to reuse items on the list. The only thing your program | |
434 | needs to do to use a history list is to initialize it and to pass its | |
435 | name to the input functions when you wish. But it is safe to modify the | |
436 | list by hand when the minibuffer input functions are not using it. | |
437 | ||
ff306b60 RS |
438 | Emacs functions that add a new element to a history list can also |
439 | delete old elements if the list gets too long. The variable | |
440 | @code{history-length} specifies the maximum length for most history | |
441 | lists. To specify a different maximum length for a particular history | |
442 | list, put the length in the @code{history-length} property of the | |
443 | history list symbol. | |
444 | ||
445 | @defvar history-length | |
446 | The value of this variable specifies the maximum length for all | |
447 | history lists that don't specify their own maximum lengths. If the | |
448 | value is @code{t}, that means there no maximum (don't delete old | |
449 | elements). | |
450 | @end defvar | |
451 | ||
969fe9b5 RS |
452 | Here are some of the standard minibuffer history list variables: |
453 | ||
3e01fd9d RS |
454 | @defvar minibuffer-history |
455 | The default history list for minibuffer history input. | |
456 | @end defvar | |
457 | ||
458 | @defvar query-replace-history | |
459 | A history list for arguments to @code{query-replace} (and similar | |
460 | arguments to other commands). | |
461 | @end defvar | |
462 | ||
463 | @defvar file-name-history | |
a9f0a989 RS |
464 | A history list for file-name arguments. |
465 | @end defvar | |
466 | ||
467 | @defvar buffer-name-history | |
a9f0a989 | 468 | A history list for buffer-name arguments. |
3e01fd9d RS |
469 | @end defvar |
470 | ||
471 | @defvar regexp-history | |
472 | A history list for regular expression arguments. | |
473 | @end defvar | |
474 | ||
475 | @defvar extended-command-history | |
476 | A history list for arguments that are names of extended commands. | |
477 | @end defvar | |
478 | ||
479 | @defvar shell-command-history | |
480 | A history list for arguments that are shell commands. | |
481 | @end defvar | |
482 | ||
483 | @defvar read-expression-history | |
484 | A history list for arguments that are Lisp expressions to evaluate. | |
485 | @end defvar | |
486 | ||
487 | @node Completion | |
488 | @section Completion | |
489 | @cindex completion | |
490 | ||
491 | @dfn{Completion} is a feature that fills in the rest of a name | |
492 | starting from an abbreviation for it. Completion works by comparing the | |
493 | user's input against a list of valid names and determining how much of | |
494 | the name is determined uniquely by what the user has typed. For | |
495 | example, when you type @kbd{C-x b} (@code{switch-to-buffer}) and then | |
496 | type the first few letters of the name of the buffer to which you wish | |
497 | to switch, and then type @key{TAB} (@code{minibuffer-complete}), Emacs | |
498 | extends the name as far as it can. | |
499 | ||
500 | Standard Emacs commands offer completion for names of symbols, files, | |
501 | buffers, and processes; with the functions in this section, you can | |
502 | implement completion for other kinds of names. | |
503 | ||
504 | The @code{try-completion} function is the basic primitive for | |
505 | completion: it returns the longest determined completion of a given | |
506 | initial string, with a given set of strings to match against. | |
507 | ||
508 | The function @code{completing-read} provides a higher-level interface | |
509 | for completion. A call to @code{completing-read} specifies how to | |
510 | determine the list of valid names. The function then activates the | |
511 | minibuffer with a local keymap that binds a few keys to commands useful | |
512 | for completion. Other functions provide convenient simple interfaces | |
513 | for reading certain kinds of names with completion. | |
514 | ||
515 | @menu | |
516 | * Basic Completion:: Low-level functions for completing strings. | |
517 | (These are too low level to use the minibuffer.) | |
518 | * Minibuffer Completion:: Invoking the minibuffer with completion. | |
519 | * Completion Commands:: Minibuffer commands that do completion. | |
520 | * High-Level Completion:: Convenient special cases of completion | |
521 | (reading buffer name, file name, etc.) | |
522 | * Reading File Names:: Using completion to read file names. | |
523 | * Programmed Completion:: Finding the completions for a given file name. | |
524 | @end menu | |
525 | ||
526 | @node Basic Completion | |
527 | @subsection Basic Completion Functions | |
528 | ||
793da230 RS |
529 | The two functions @code{try-completion} and @code{all-completions} |
530 | have nothing in themselves to do with minibuffers. We describe them in | |
531 | this chapter so as to keep them near the higher-level completion | |
532 | features that do use the minibuffer. | |
533 | ||
3e01fd9d RS |
534 | @defun try-completion string collection &optional predicate |
535 | This function returns the longest common substring of all possible | |
536 | completions of @var{string} in @var{collection}. The value of | |
793da230 | 537 | @var{collection} must be an alist, an obarray, or a function that |
3e01fd9d RS |
538 | implements a virtual set of strings (see below). |
539 | ||
540 | Completion compares @var{string} against each of the permissible | |
541 | completions specified by @var{collection}; if the beginning of the | |
542 | permissible completion equals @var{string}, it matches. If no permissible | |
543 | completions match, @code{try-completion} returns @code{nil}. If only | |
544 | one permissible completion matches, and the match is exact, then | |
545 | @code{try-completion} returns @code{t}. Otherwise, the value is the | |
546 | longest initial sequence common to all the permissible completions that | |
547 | match. | |
548 | ||
549 | If @var{collection} is an alist (@pxref{Association Lists}), the | |
550 | @sc{car}s of the alist elements form the set of permissible completions. | |
551 | ||
552 | @cindex obarray in completion | |
553 | If @var{collection} is an obarray (@pxref{Creating Symbols}), the names | |
554 | of all symbols in the obarray form the set of permissible completions. The | |
555 | global variable @code{obarray} holds an obarray containing the names of | |
556 | all interned Lisp symbols. | |
557 | ||
558 | Note that the only valid way to make a new obarray is to create it | |
559 | empty and then add symbols to it one by one using @code{intern}. | |
560 | Also, you cannot intern a given symbol in more than one obarray. | |
561 | ||
562 | If the argument @var{predicate} is non-@code{nil}, then it must be a | |
563 | function of one argument. It is used to test each possible match, and | |
564 | the match is accepted only if @var{predicate} returns non-@code{nil}. | |
565 | The argument given to @var{predicate} is either a cons cell from the alist | |
566 | (the @sc{car} of which is a string) or else it is a symbol (@emph{not} a | |
567 | symbol name) from the obarray. | |
568 | ||
793da230 RS |
569 | You can also use a symbol that is a function as @var{collection}. Then |
570 | the function is solely responsible for performing completion; | |
3e01fd9d RS |
571 | @code{try-completion} returns whatever this function returns. The |
572 | function is called with three arguments: @var{string}, @var{predicate} | |
573 | and @code{nil}. (The reason for the third argument is so that the same | |
574 | function can be used in @code{all-completions} and do the appropriate | |
575 | thing in either case.) @xref{Programmed Completion}. | |
576 | ||
577 | In the first of the following examples, the string @samp{foo} is | |
578 | matched by three of the alist @sc{car}s. All of the matches begin with | |
579 | the characters @samp{fooba}, so that is the result. In the second | |
580 | example, there is only one possible match, and it is exact, so the value | |
581 | is @code{t}. | |
582 | ||
583 | @smallexample | |
584 | @group | |
177c0ea7 | 585 | (try-completion |
3e01fd9d RS |
586 | "foo" |
587 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))) | |
588 | @result{} "fooba" | |
589 | @end group | |
590 | ||
591 | @group | |
592 | (try-completion "foo" '(("barfoo" 2) ("foo" 3))) | |
593 | @result{} t | |
594 | @end group | |
595 | @end smallexample | |
596 | ||
597 | In the following example, numerous symbols begin with the characters | |
598 | @samp{forw}, and all of them begin with the word @samp{forward}. In | |
599 | most of the symbols, this is followed with a @samp{-}, but not in all, | |
600 | so no more than @samp{forward} can be completed. | |
601 | ||
602 | @smallexample | |
603 | @group | |
604 | (try-completion "forw" obarray) | |
605 | @result{} "forward" | |
606 | @end group | |
607 | @end smallexample | |
608 | ||
609 | Finally, in the following example, only two of the three possible | |
610 | matches pass the predicate @code{test} (the string @samp{foobaz} is | |
611 | too short). Both of those begin with the string @samp{foobar}. | |
612 | ||
613 | @smallexample | |
614 | @group | |
177c0ea7 | 615 | (defun test (s) |
3e01fd9d RS |
616 | (> (length (car s)) 6)) |
617 | @result{} test | |
618 | @end group | |
619 | @group | |
177c0ea7 | 620 | (try-completion |
3e01fd9d | 621 | "foo" |
177c0ea7 | 622 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) |
793da230 | 623 | 'test) |
3e01fd9d RS |
624 | @result{} "foobar" |
625 | @end group | |
626 | @end smallexample | |
627 | @end defun | |
628 | ||
22697dac | 629 | @defun all-completions string collection &optional predicate nospace |
3e01fd9d | 630 | This function returns a list of all possible completions of |
72821190 RS |
631 | @var{string}. The arguments to this function (aside from @var{nospace}) |
632 | are the same as those of @code{try-completion}. If @var{nospace} is | |
633 | non-@code{nil}, completions that start with a space are ignored unless | |
634 | @var{string} also starts with a space. | |
3e01fd9d RS |
635 | |
636 | If @var{collection} is a function, it is called with three arguments: | |
637 | @var{string}, @var{predicate} and @code{t}; then @code{all-completions} | |
638 | returns whatever the function returns. @xref{Programmed Completion}. | |
639 | ||
640 | Here is an example, using the function @code{test} shown in the | |
641 | example for @code{try-completion}: | |
642 | ||
643 | @smallexample | |
644 | @group | |
177c0ea7 | 645 | (defun test (s) |
3e01fd9d RS |
646 | (> (length (car s)) 6)) |
647 | @result{} test | |
648 | @end group | |
649 | ||
650 | @group | |
177c0ea7 | 651 | (all-completions |
3e01fd9d RS |
652 | "foo" |
653 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) | |
793da230 | 654 | 'test) |
3e01fd9d RS |
655 | @result{} ("foobar1" "foobar2") |
656 | @end group | |
657 | @end smallexample | |
658 | @end defun | |
659 | ||
660 | @defvar completion-ignore-case | |
177c0ea7 | 661 | If the value of this variable is |
3e01fd9d RS |
662 | non-@code{nil}, Emacs does not consider case significant in completion. |
663 | @end defvar | |
664 | ||
3e01fd9d RS |
665 | @node Minibuffer Completion |
666 | @subsection Completion and the Minibuffer | |
667 | ||
668 | This section describes the basic interface for reading from the | |
669 | minibuffer with completion. | |
670 | ||
f9f59935 | 671 | @defun completing-read prompt collection &optional predicate require-match initial hist default inherit-input-method |
3e01fd9d RS |
672 | This function reads a string in the minibuffer, assisting the user by |
673 | providing completion. It activates the minibuffer with prompt | |
969fe9b5 | 674 | @var{prompt}, which must be a string. |
3e01fd9d RS |
675 | |
676 | The actual completion is done by passing @var{collection} and | |
677 | @var{predicate} to the function @code{try-completion}. This happens in | |
678 | certain commands bound in the local keymaps used for completion. | |
679 | ||
f9f59935 RS |
680 | If @var{require-match} is @code{nil}, the exit commands work regardless |
681 | of the input in the minibuffer. If @var{require-match} is @code{t}, the | |
682 | usual minibuffer exit commands won't exit unless the input completes to | |
683 | an element of @var{collection}. If @var{require-match} is neither | |
684 | @code{nil} nor @code{t}, then the exit commands won't exit unless the | |
685 | input already in the buffer matches an element of @var{collection}. | |
686 | ||
687 | However, empty input is always permitted, regardless of the value of | |
688 | @var{require-match}; in that case, @code{completing-read} returns | |
969fe9b5 RS |
689 | @var{default}. The value of @var{default} (if non-@code{nil}) is also |
690 | available to the user through the history commands. | |
3e01fd9d | 691 | |
ece23c27 | 692 | The user can exit with null input by typing @key{RET} with an empty |
6ecb21f1 RS |
693 | minibuffer. Then @code{completing-read} returns @code{""}. This is how |
694 | the user requests whatever default the command uses for the value being | |
695 | read. The user can return using @key{RET} in this way regardless of the | |
696 | value of @var{require-match}, and regardless of whether the empty string | |
697 | is included in @var{collection}. | |
ece23c27 | 698 | |
3e01fd9d RS |
699 | The function @code{completing-read} works by calling |
700 | @code{read-minibuffer}. It uses @code{minibuffer-local-completion-map} | |
701 | as the keymap if @var{require-match} is @code{nil}, and uses | |
702 | @code{minibuffer-local-must-match-map} if @var{require-match} is | |
793da230 | 703 | non-@code{nil}. @xref{Completion Commands}. |
3e01fd9d RS |
704 | |
705 | The argument @var{hist} specifies which history list variable to use for | |
706 | saving the input and for minibuffer history commands. It defaults to | |
707 | @code{minibuffer-history}. @xref{Minibuffer History}. | |
708 | ||
969fe9b5 RS |
709 | If @var{initial} is non-@code{nil}, @code{completing-read} inserts it |
710 | into the minibuffer as part of the input. Then it allows the user to | |
711 | edit the input, providing several commands to attempt completion. | |
712 | In most cases, we recommend using @var{default}, and not @var{initial}. | |
f9f59935 | 713 | |
70c750c0 RS |
714 | @strong{We discourage use of a non-@code{nil} value for |
715 | @var{initial}}, because it is an intrusive interface. The history | |
b9332010 RS |
716 | list feature (which did not exist when we introduced @var{initial}) |
717 | offers a far more convenient and general way for the user to get the | |
718 | default and edit it, and it is always available. | |
70c750c0 | 719 | |
f9f59935 | 720 | If the argument @var{inherit-input-method} is non-@code{nil}, then the |
1911e6e5 | 721 | minibuffer inherits the current input method (@pxref{Input |
a9f0a989 RS |
722 | Methods}) and the setting of @code{enable-multibyte-characters} |
723 | (@pxref{Text Representations}) from whichever buffer was current before | |
724 | entering the minibuffer. | |
f9f59935 | 725 | |
3e01fd9d RS |
726 | Completion ignores case when comparing the input against the possible |
727 | matches, if the built-in variable @code{completion-ignore-case} is | |
728 | non-@code{nil}. @xref{Basic Completion}. | |
729 | ||
730 | Here's an example of using @code{completing-read}: | |
731 | ||
732 | @smallexample | |
733 | @group | |
734 | (completing-read | |
735 | "Complete a foo: " | |
736 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) | |
737 | nil t "fo") | |
738 | @end group | |
739 | ||
740 | @group | |
177c0ea7 | 741 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
742 | ;; @r{the following appears in the minibuffer:} |
743 | ||
744 | ---------- Buffer: Minibuffer ---------- | |
745 | Complete a foo: fo@point{} | |
746 | ---------- Buffer: Minibuffer ---------- | |
747 | @end group | |
748 | @end smallexample | |
749 | ||
750 | @noindent | |
751 | If the user then types @kbd{@key{DEL} @key{DEL} b @key{RET}}, | |
752 | @code{completing-read} returns @code{barfoo}. | |
753 | ||
754 | The @code{completing-read} function binds three variables to pass | |
793da230 RS |
755 | information to the commands that actually do completion. These |
756 | variables are @code{minibuffer-completion-table}, | |
757 | @code{minibuffer-completion-predicate} and | |
758 | @code{minibuffer-completion-confirm}. For more information about them, | |
759 | see @ref{Completion Commands}. | |
3e01fd9d RS |
760 | @end defun |
761 | ||
762 | @node Completion Commands | |
8241495d | 763 | @subsection Minibuffer Commands that Do Completion |
3e01fd9d RS |
764 | |
765 | This section describes the keymaps, commands and user options used in | |
766 | the minibuffer to do completion. | |
767 | ||
768 | @defvar minibuffer-local-completion-map | |
793da230 | 769 | @code{completing-read} uses this value as the local keymap when an |
3e01fd9d RS |
770 | exact match of one of the completions is not required. By default, this |
771 | keymap makes the following bindings: | |
772 | ||
773 | @table @asis | |
774 | @item @kbd{?} | |
775 | @code{minibuffer-completion-help} | |
776 | ||
777 | @item @key{SPC} | |
778 | @code{minibuffer-complete-word} | |
779 | ||
780 | @item @key{TAB} | |
781 | @code{minibuffer-complete} | |
782 | @end table | |
783 | ||
784 | @noindent | |
793da230 RS |
785 | with other characters bound as in @code{minibuffer-local-map} |
786 | (@pxref{Text from Minibuffer}). | |
3e01fd9d RS |
787 | @end defvar |
788 | ||
789 | @defvar minibuffer-local-must-match-map | |
790 | @code{completing-read} uses this value as the local keymap when an | |
791 | exact match of one of the completions is required. Therefore, no keys | |
793da230 | 792 | are bound to @code{exit-minibuffer}, the command that exits the |
3e01fd9d RS |
793 | minibuffer unconditionally. By default, this keymap makes the following |
794 | bindings: | |
795 | ||
796 | @table @asis | |
797 | @item @kbd{?} | |
798 | @code{minibuffer-completion-help} | |
799 | ||
800 | @item @key{SPC} | |
801 | @code{minibuffer-complete-word} | |
802 | ||
803 | @item @key{TAB} | |
804 | @code{minibuffer-complete} | |
805 | ||
969fe9b5 | 806 | @item @kbd{C-j} |
3e01fd9d RS |
807 | @code{minibuffer-complete-and-exit} |
808 | ||
809 | @item @key{RET} | |
810 | @code{minibuffer-complete-and-exit} | |
811 | @end table | |
812 | ||
813 | @noindent | |
814 | with other characters bound as in @code{minibuffer-local-map}. | |
815 | @end defvar | |
816 | ||
817 | @defvar minibuffer-completion-table | |
818 | The value of this variable is the alist or obarray used for completion | |
819 | in the minibuffer. This is the global variable that contains what | |
820 | @code{completing-read} passes to @code{try-completion}. It is used by | |
821 | minibuffer completion commands such as @code{minibuffer-complete-word}. | |
822 | @end defvar | |
823 | ||
824 | @defvar minibuffer-completion-predicate | |
825 | This variable's value is the predicate that @code{completing-read} | |
826 | passes to @code{try-completion}. The variable is also used by the other | |
827 | minibuffer completion functions. | |
828 | @end defvar | |
829 | ||
830 | @deffn Command minibuffer-complete-word | |
831 | This function completes the minibuffer contents by at most a single | |
832 | word. Even if the minibuffer contents have only one completion, | |
833 | @code{minibuffer-complete-word} does not add any characters beyond the | |
834 | first character that is not a word constituent. @xref{Syntax Tables}. | |
835 | @end deffn | |
836 | ||
837 | @deffn Command minibuffer-complete | |
838 | This function completes the minibuffer contents as far as possible. | |
839 | @end deffn | |
840 | ||
841 | @deffn Command minibuffer-complete-and-exit | |
842 | This function completes the minibuffer contents, and exits if | |
843 | confirmation is not required, i.e., if | |
2770e862 | 844 | @code{minibuffer-completion-confirm} is @code{nil}. If confirmation |
793da230 RS |
845 | @emph{is} required, it is given by repeating this command |
846 | immediately---the command is programmed to work without confirmation | |
847 | when run twice in succession. | |
3e01fd9d RS |
848 | @end deffn |
849 | ||
850 | @defvar minibuffer-completion-confirm | |
851 | When the value of this variable is non-@code{nil}, Emacs asks for | |
852 | confirmation of a completion before exiting the minibuffer. The | |
853 | function @code{minibuffer-complete-and-exit} checks the value of this | |
854 | variable before it exits. | |
855 | @end defvar | |
856 | ||
857 | @deffn Command minibuffer-completion-help | |
858 | This function creates a list of the possible completions of the | |
859 | current minibuffer contents. It works by calling @code{all-completions} | |
860 | using the value of the variable @code{minibuffer-completion-table} as | |
861 | the @var{collection} argument, and the value of | |
862 | @code{minibuffer-completion-predicate} as the @var{predicate} argument. | |
863 | The list of completions is displayed as text in a buffer named | |
864 | @samp{*Completions*}. | |
865 | @end deffn | |
866 | ||
867 | @defun display-completion-list completions | |
868 | This function displays @var{completions} to the stream in | |
3e099569 | 869 | @code{standard-output}, usually a buffer. (@xref{Read and Print}, for more |
3e01fd9d RS |
870 | information about streams.) The argument @var{completions} is normally |
871 | a list of completions just returned by @code{all-completions}, but it | |
872 | does not have to be. Each element may be a symbol or a string, either | |
873 | of which is simply printed, or a list of two strings, which is printed | |
874 | as if the strings were concatenated. | |
875 | ||
876 | This function is called by @code{minibuffer-completion-help}. The | |
877 | most common way to use it is together with | |
878 | @code{with-output-to-temp-buffer}, like this: | |
879 | ||
880 | @example | |
881 | (with-output-to-temp-buffer "*Completions*" | |
882 | (display-completion-list | |
883 | (all-completions (buffer-string) my-alist))) | |
884 | @end example | |
885 | @end defun | |
886 | ||
887 | @defopt completion-auto-help | |
888 | If this variable is non-@code{nil}, the completion commands | |
889 | automatically display a list of possible completions whenever nothing | |
890 | can be completed because the next character is not uniquely determined. | |
891 | @end defopt | |
892 | ||
893 | @node High-Level Completion | |
894 | @subsection High-Level Completion Functions | |
895 | ||
896 | This section describes the higher-level convenient functions for | |
897 | reading certain sorts of names with completion. | |
898 | ||
bfe721d1 KH |
899 | In most cases, you should not call these functions in the middle of a |
900 | Lisp function. When possible, do all minibuffer input as part of | |
a9f0a989 RS |
901 | reading the arguments for a command, in the @code{interactive} |
902 | specification. @xref{Defining Commands}. | |
bfe721d1 | 903 | |
3e01fd9d RS |
904 | @defun read-buffer prompt &optional default existing |
905 | This function reads the name of a buffer and returns it as a string. | |
906 | The argument @var{default} is the default name to use, the value to | |
907 | return if the user exits with an empty minibuffer. If non-@code{nil}, | |
908 | it should be a string or a buffer. It is mentioned in the prompt, but | |
909 | is not inserted in the minibuffer as initial input. | |
910 | ||
911 | If @var{existing} is non-@code{nil}, then the name specified must be | |
793da230 RS |
912 | that of an existing buffer. The usual commands to exit the minibuffer |
913 | do not exit if the text is not valid, and @key{RET} does completion to | |
914 | attempt to find a valid name. (However, @var{default} is not checked | |
915 | for validity; it is returned, whatever it is, if the user exits with the | |
916 | minibuffer empty.) | |
3e01fd9d RS |
917 | |
918 | In the following example, the user enters @samp{minibuffer.t}, and | |
919 | then types @key{RET}. The argument @var{existing} is @code{t}, and the | |
920 | only buffer name starting with the given input is | |
921 | @samp{minibuffer.texi}, so that name is the value. | |
922 | ||
923 | @example | |
924 | (read-buffer "Buffer name? " "foo" t) | |
925 | @group | |
177c0ea7 | 926 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
927 | ;; @r{the following prompt appears,} |
928 | ;; @r{with an empty minibuffer:} | |
929 | @end group | |
930 | ||
931 | @group | |
932 | ---------- Buffer: Minibuffer ---------- | |
933 | Buffer name? (default foo) @point{} | |
934 | ---------- Buffer: Minibuffer ---------- | |
935 | @end group | |
936 | ||
937 | @group | |
938 | ;; @r{The user types @kbd{minibuffer.t @key{RET}}.} | |
939 | @result{} "minibuffer.texi" | |
940 | @end group | |
941 | @end example | |
942 | @end defun | |
943 | ||
f9f59935 RS |
944 | @defvar read-buffer-function |
945 | This variable specifies how to read buffer names. For example, if you | |
946 | set this variable to @code{iswitchb-read-buffer}, all Emacs commands | |
947 | that call @code{read-buffer} to read a buffer name will actually use the | |
948 | @code{iswitchb} package to read it. | |
949 | @end defvar | |
950 | ||
951 | @defun read-command prompt &optional default | |
3e01fd9d RS |
952 | This function reads the name of a command and returns it as a Lisp |
953 | symbol. The argument @var{prompt} is used as in | |
954 | @code{read-from-minibuffer}. Recall that a command is anything for | |
955 | which @code{commandp} returns @code{t}, and a command name is a symbol | |
956 | for which @code{commandp} returns @code{t}. @xref{Interactive Call}. | |
957 | ||
f9f59935 | 958 | The argument @var{default} specifies what to return if the user enters |
969fe9b5 RS |
959 | null input. It can be a symbol or a string; if it is a string, |
960 | @code{read-command} interns it before returning it. If @var{default} is | |
961 | @code{nil}, that means no default has been specified; then if the user | |
962 | enters null input, the return value is @code{nil}. | |
f9f59935 | 963 | |
3e01fd9d RS |
964 | @example |
965 | (read-command "Command name? ") | |
966 | ||
967 | @group | |
177c0ea7 | 968 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
969 | ;; @r{the following prompt appears with an empty minibuffer:} |
970 | @end group | |
971 | ||
972 | @group | |
177c0ea7 JB |
973 | ---------- Buffer: Minibuffer ---------- |
974 | Command name? | |
3e01fd9d RS |
975 | ---------- Buffer: Minibuffer ---------- |
976 | @end group | |
977 | @end example | |
978 | ||
979 | @noindent | |
980 | If the user types @kbd{forward-c @key{RET}}, then this function returns | |
981 | @code{forward-char}. | |
982 | ||
9e2b495b RS |
983 | The @code{read-command} function is a simplified interface to |
984 | @code{completing-read}. It uses the variable @code{obarray} so as to | |
985 | complete in the set of extant Lisp symbols, and it uses the | |
3e01fd9d RS |
986 | @code{commandp} predicate so as to accept only command names: |
987 | ||
988 | @cindex @code{commandp} example | |
989 | @example | |
990 | @group | |
991 | (read-command @var{prompt}) | |
992 | @equiv{} | |
177c0ea7 | 993 | (intern (completing-read @var{prompt} obarray |
3e01fd9d RS |
994 | 'commandp t nil)) |
995 | @end group | |
996 | @end example | |
997 | @end defun | |
998 | ||
f9f59935 | 999 | @defun read-variable prompt &optional default |
3e01fd9d RS |
1000 | This function reads the name of a user variable and returns it as a |
1001 | symbol. | |
1002 | ||
f9f59935 | 1003 | The argument @var{default} specifies what to return if the user enters |
969fe9b5 RS |
1004 | null input. It can be a symbol or a string; if it is a string, |
1005 | @code{read-variable} interns it before returning it. If @var{default} | |
1006 | is @code{nil}, that means no default has been specified; then if the | |
1007 | user enters null input, the return value is @code{nil}. | |
f9f59935 | 1008 | |
3e01fd9d RS |
1009 | @example |
1010 | @group | |
1011 | (read-variable "Variable name? ") | |
1012 | ||
177c0ea7 JB |
1013 | ;; @r{After evaluation of the preceding expression,} |
1014 | ;; @r{the following prompt appears,} | |
3e01fd9d RS |
1015 | ;; @r{with an empty minibuffer:} |
1016 | @end group | |
1017 | ||
1018 | @group | |
1019 | ---------- Buffer: Minibuffer ---------- | |
1020 | Variable name? @point{} | |
1021 | ---------- Buffer: Minibuffer ---------- | |
1022 | @end group | |
1023 | @end example | |
1024 | ||
1025 | @noindent | |
1026 | If the user then types @kbd{fill-p @key{RET}}, @code{read-variable} | |
1027 | returns @code{fill-prefix}. | |
1028 | ||
1029 | This function is similar to @code{read-command}, but uses the | |
1030 | predicate @code{user-variable-p} instead of @code{commandp}: | |
1031 | ||
1032 | @cindex @code{user-variable-p} example | |
1033 | @example | |
1034 | @group | |
1035 | (read-variable @var{prompt}) | |
1036 | @equiv{} | |
1037 | (intern | |
1038 | (completing-read @var{prompt} obarray | |
1039 | 'user-variable-p t nil)) | |
1040 | @end group | |
1041 | @end example | |
1042 | @end defun | |
1043 | ||
969fe9b5 | 1044 | See also the functions @code{read-coding-system} and |
1911e6e5 | 1045 | @code{read-non-nil-coding-system}, in @ref{User-Chosen Coding Systems}. |
f9f59935 | 1046 | |
3e01fd9d RS |
1047 | @node Reading File Names |
1048 | @subsection Reading File Names | |
1049 | ||
1050 | Here is another high-level completion function, designed for reading a | |
1051 | file name. It provides special features including automatic insertion | |
1052 | of the default directory. | |
1053 | ||
1054 | @defun read-file-name prompt &optional directory default existing initial | |
1055 | This function reads a file name in the minibuffer, prompting with | |
1056 | @var{prompt} and providing completion. If @var{default} is | |
1057 | non-@code{nil}, then the function returns @var{default} if the user just | |
793da230 RS |
1058 | types @key{RET}. @var{default} is not checked for validity; it is |
1059 | returned, whatever it is, if the user exits with the minibuffer empty. | |
3e01fd9d | 1060 | |
793da230 RS |
1061 | If @var{existing} is non-@code{nil}, then the user must specify the name |
1062 | of an existing file; @key{RET} performs completion to make the name | |
1063 | valid if possible, and then refuses to exit if it is not valid. If the | |
1064 | value of @var{existing} is neither @code{nil} nor @code{t}, then | |
1065 | @key{RET} also requires confirmation after completion. If | |
1066 | @var{existing} is @code{nil}, then the name of a nonexistent file is | |
1067 | acceptable. | |
3e01fd9d RS |
1068 | |
1069 | The argument @var{directory} specifies the directory to use for | |
793da230 RS |
1070 | completion of relative file names. If @code{insert-default-directory} |
1071 | is non-@code{nil}, @var{directory} is also inserted in the minibuffer as | |
1072 | initial input. It defaults to the current buffer's value of | |
1073 | @code{default-directory}. | |
3e01fd9d RS |
1074 | |
1075 | @c Emacs 19 feature | |
1076 | If you specify @var{initial}, that is an initial file name to insert in | |
1911e6e5 | 1077 | the buffer (after @var{directory}, if that is inserted). In this |
793da230 RS |
1078 | case, point goes at the beginning of @var{initial}. The default for |
1079 | @var{initial} is @code{nil}---don't insert any file name. To see what | |
969fe9b5 RS |
1080 | @var{initial} does, try the command @kbd{C-x C-v}. @strong{Note:} we |
1081 | recommend using @var{default} rather than @var{initial} in most cases. | |
3e01fd9d | 1082 | |
177c0ea7 | 1083 | Here is an example: |
3e01fd9d RS |
1084 | |
1085 | @example | |
1086 | @group | |
1087 | (read-file-name "The file is ") | |
1088 | ||
177c0ea7 | 1089 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
1090 | ;; @r{the following appears in the minibuffer:} |
1091 | @end group | |
1092 | ||
1093 | @group | |
1094 | ---------- Buffer: Minibuffer ---------- | |
1095 | The file is /gp/gnu/elisp/@point{} | |
1096 | ---------- Buffer: Minibuffer ---------- | |
1097 | @end group | |
1098 | @end example | |
1099 | ||
1100 | @noindent | |
1101 | Typing @kbd{manual @key{TAB}} results in the following: | |
1102 | ||
1103 | @example | |
1104 | @group | |
1105 | ---------- Buffer: Minibuffer ---------- | |
1106 | The file is /gp/gnu/elisp/manual.texi@point{} | |
1107 | ---------- Buffer: Minibuffer ---------- | |
1108 | @end group | |
1109 | @end example | |
1110 | ||
1111 | @c Wordy to avoid overfull hbox in smallbook mode. | |
1112 | @noindent | |
1113 | If the user types @key{RET}, @code{read-file-name} returns the file name | |
1114 | as the string @code{"/gp/gnu/elisp/manual.texi"}. | |
1115 | @end defun | |
1116 | ||
1117 | @defopt insert-default-directory | |
1118 | This variable is used by @code{read-file-name}. Its value controls | |
1119 | whether @code{read-file-name} starts by placing the name of the default | |
1120 | directory in the minibuffer, plus the initial file name if any. If the | |
1121 | value of this variable is @code{nil}, then @code{read-file-name} does | |
bfe721d1 KH |
1122 | not place any initial input in the minibuffer (unless you specify |
1123 | initial input with the @var{initial} argument). In that case, the | |
3e01fd9d RS |
1124 | default directory is still used for completion of relative file names, |
1125 | but is not displayed. | |
1126 | ||
1127 | For example: | |
1128 | ||
1129 | @example | |
1130 | @group | |
1131 | ;; @r{Here the minibuffer starts out with the default directory.} | |
1132 | (let ((insert-default-directory t)) | |
1133 | (read-file-name "The file is ")) | |
1134 | @end group | |
1135 | ||
1136 | @group | |
1137 | ---------- Buffer: Minibuffer ---------- | |
1138 | The file is ~lewis/manual/@point{} | |
1139 | ---------- Buffer: Minibuffer ---------- | |
1140 | @end group | |
1141 | ||
1142 | @group | |
1143 | ;; @r{Here the minibuffer is empty and only the prompt} | |
1144 | ;; @r{appears on its line.} | |
1145 | (let ((insert-default-directory nil)) | |
1146 | (read-file-name "The file is ")) | |
1147 | @end group | |
1148 | ||
1149 | @group | |
1150 | ---------- Buffer: Minibuffer ---------- | |
1151 | The file is @point{} | |
1152 | ---------- Buffer: Minibuffer ---------- | |
1153 | @end group | |
1154 | @end example | |
1155 | @end defopt | |
1156 | ||
1157 | @node Programmed Completion | |
1158 | @subsection Programmed Completion | |
1159 | @cindex programmed completion | |
1160 | ||
1161 | Sometimes it is not possible to create an alist or an obarray | |
1162 | containing all the intended possible completions. In such a case, you | |
1163 | can supply your own function to compute the completion of a given string. | |
1164 | This is called @dfn{programmed completion}. | |
1165 | ||
1166 | To use this feature, pass a symbol with a function definition as the | |
793da230 RS |
1167 | @var{collection} argument to @code{completing-read}. The function |
1168 | @code{completing-read} arranges to pass your completion function along | |
1169 | to @code{try-completion} and @code{all-completions}, which will then let | |
1170 | your function do all the work. | |
3e01fd9d RS |
1171 | |
1172 | The completion function should accept three arguments: | |
1173 | ||
1174 | @itemize @bullet | |
1175 | @item | |
1176 | The string to be completed. | |
1177 | ||
1178 | @item | |
1179 | The predicate function to filter possible matches, or @code{nil} if | |
1180 | none. Your function should call the predicate for each possible match, | |
1181 | and ignore the possible match if the predicate returns @code{nil}. | |
1182 | ||
1183 | @item | |
1184 | A flag specifying the type of operation. | |
1185 | @end itemize | |
1186 | ||
1187 | There are three flag values for three operations: | |
1188 | ||
1189 | @itemize @bullet | |
1190 | @item | |
1191 | @code{nil} specifies @code{try-completion}. The completion function | |
1192 | should return the completion of the specified string, or @code{t} if the | |
d595eca0 RS |
1193 | string is a unique and exact match already, or @code{nil} if the string |
1194 | matches no possibility. | |
1195 | ||
1196 | If the string is an exact match for one possibility, but also matches | |
969fe9b5 | 1197 | other longer possibilities, the function should return the string, not |
d595eca0 | 1198 | @code{t}. |
3e01fd9d RS |
1199 | |
1200 | @item | |
1201 | @code{t} specifies @code{all-completions}. The completion function | |
1202 | should return a list of all possible completions of the specified | |
1203 | string. | |
1204 | ||
1205 | @item | |
1206 | @code{lambda} specifies a test for an exact match. The completion | |
1207 | function should return @code{t} if the specified string is an exact | |
1208 | match for some possibility; @code{nil} otherwise. | |
1209 | @end itemize | |
1210 | ||
1211 | It would be consistent and clean for completion functions to allow | |
bfe721d1 | 1212 | lambda expressions (lists that are functions) as well as function |
3e01fd9d RS |
1213 | symbols as @var{collection}, but this is impossible. Lists as |
1214 | completion tables are already assigned another meaning---as alists. It | |
1215 | would be unreliable to fail to handle an alist normally because it is | |
1216 | also a possible function. So you must arrange for any function you wish | |
1217 | to use for completion to be encapsulated in a symbol. | |
1218 | ||
1219 | Emacs uses programmed completion when completing file names. | |
1220 | @xref{File Name Completion}. | |
1221 | ||
1222 | @node Yes-or-No Queries | |
1223 | @section Yes-or-No Queries | |
1224 | @cindex asking the user questions | |
1225 | @cindex querying the user | |
1226 | @cindex yes-or-no questions | |
1227 | ||
1228 | This section describes functions used to ask the user a yes-or-no | |
1229 | question. The function @code{y-or-n-p} can be answered with a single | |
1230 | character; it is useful for questions where an inadvertent wrong answer | |
1231 | will not have serious consequences. @code{yes-or-no-p} is suitable for | |
1232 | more momentous questions, since it requires three or four characters to | |
1233 | answer. | |
1234 | ||
3e099569 RS |
1235 | If either of these functions is called in a command that was invoked |
1236 | using the mouse---more precisely, if @code{last-nonmenu-event} | |
1237 | (@pxref{Command Loop Info}) is either @code{nil} or a list---then it | |
1238 | uses a dialog box or pop-up menu to ask the question. Otherwise, it | |
1239 | uses keyboard input. You can force use of the mouse or use of keyboard | |
1240 | input by binding @code{last-nonmenu-event} to a suitable value around | |
1241 | the call. | |
1242 | ||
3e01fd9d RS |
1243 | Strictly speaking, @code{yes-or-no-p} uses the minibuffer and |
1244 | @code{y-or-n-p} does not; but it seems best to describe them together. | |
1245 | ||
1246 | @defun y-or-n-p prompt | |
793da230 | 1247 | This function asks the user a question, expecting input in the echo |
3e01fd9d RS |
1248 | area. It returns @code{t} if the user types @kbd{y}, @code{nil} if the |
1249 | user types @kbd{n}. This function also accepts @key{SPC} to mean yes | |
1250 | and @key{DEL} to mean no. It accepts @kbd{C-]} to mean ``quit'', like | |
1251 | @kbd{C-g}, because the question might look like a minibuffer and for | |
1252 | that reason the user might try to use @kbd{C-]} to get out. The answer | |
1253 | is a single character, with no @key{RET} needed to terminate it. Upper | |
1254 | and lower case are equivalent. | |
1255 | ||
793da230 | 1256 | ``Asking the question'' means printing @var{prompt} in the echo area, |
3e01fd9d RS |
1257 | followed by the string @w{@samp{(y or n) }}. If the input is not one of |
1258 | the expected answers (@kbd{y}, @kbd{n}, @kbd{@key{SPC}}, | |
1259 | @kbd{@key{DEL}}, or something that quits), the function responds | |
1260 | @samp{Please answer y or n.}, and repeats the request. | |
1261 | ||
793da230 | 1262 | This function does not actually use the minibuffer, since it does not |
3e01fd9d RS |
1263 | allow editing of the answer. It actually uses the echo area (@pxref{The |
1264 | Echo Area}), which uses the same screen space as the minibuffer. The | |
1265 | cursor moves to the echo area while the question is being asked. | |
1266 | ||
793da230 | 1267 | The answers and their meanings, even @samp{y} and @samp{n}, are not |
3e01fd9d RS |
1268 | hardwired. The keymap @code{query-replace-map} specifies them. |
1269 | @xref{Search and Replace}. | |
1270 | ||
793da230 | 1271 | In the following example, the user first types @kbd{q}, which is |
3e01fd9d RS |
1272 | invalid. At the next prompt the user types @kbd{y}. |
1273 | ||
1274 | @smallexample | |
1275 | @group | |
1276 | (y-or-n-p "Do you need a lift? ") | |
1277 | ||
177c0ea7 | 1278 | ;; @r{After evaluation of the preceding expression,} |
3e01fd9d RS |
1279 | ;; @r{the following prompt appears in the echo area:} |
1280 | @end group | |
1281 | ||
1282 | @group | |
1283 | ---------- Echo area ---------- | |
177c0ea7 | 1284 | Do you need a lift? (y or n) |
3e01fd9d RS |
1285 | ---------- Echo area ---------- |
1286 | @end group | |
1287 | ||
1288 | ;; @r{If the user then types @kbd{q}, the following appears:} | |
1289 | ||
1290 | @group | |
1291 | ---------- Echo area ---------- | |
177c0ea7 | 1292 | Please answer y or n. Do you need a lift? (y or n) |
3e01fd9d RS |
1293 | ---------- Echo area ---------- |
1294 | @end group | |
1295 | ||
1296 | ;; @r{When the user types a valid answer,} | |
1297 | ;; @r{it is displayed after the question:} | |
1298 | ||
1299 | @group | |
1300 | ---------- Echo area ---------- | |
1301 | Do you need a lift? (y or n) y | |
1302 | ---------- Echo area ---------- | |
1303 | @end group | |
1304 | @end smallexample | |
1305 | ||
1306 | @noindent | |
1307 | We show successive lines of echo area messages, but only one actually | |
1308 | appears on the screen at a time. | |
1309 | @end defun | |
1310 | ||
48a58303 RS |
1311 | @defun y-or-n-p-with-timeout prompt seconds default-value |
1312 | Like @code{y-or-n-p}, except that if the user fails to answer within | |
1313 | @var{seconds} seconds, this function stops waiting and returns | |
1314 | @var{default-value}. It works by setting up a timer; see @ref{Timers}. | |
1315 | The argument @var{seconds} may be an integer or a floating point number. | |
1316 | @end defun | |
1317 | ||
3e01fd9d | 1318 | @defun yes-or-no-p prompt |
793da230 RS |
1319 | This function asks the user a question, expecting input in the |
1320 | minibuffer. It returns @code{t} if the user enters @samp{yes}, | |
1321 | @code{nil} if the user types @samp{no}. The user must type @key{RET} to | |
1322 | finalize the response. Upper and lower case are equivalent. | |
3e01fd9d | 1323 | |
793da230 | 1324 | @code{yes-or-no-p} starts by displaying @var{prompt} in the echo area, |
3e01fd9d RS |
1325 | followed by @w{@samp{(yes or no) }}. The user must type one of the |
1326 | expected responses; otherwise, the function responds @samp{Please answer | |
1327 | yes or no.}, waits about two seconds and repeats the request. | |
1328 | ||
793da230 | 1329 | @code{yes-or-no-p} requires more work from the user than |
3e01fd9d RS |
1330 | @code{y-or-n-p} and is appropriate for more crucial decisions. |
1331 | ||
3e01fd9d RS |
1332 | Here is an example: |
1333 | ||
1334 | @smallexample | |
1335 | @group | |
1336 | (yes-or-no-p "Do you really want to remove everything? ") | |
1337 | ||
177c0ea7 JB |
1338 | ;; @r{After evaluation of the preceding expression,} |
1339 | ;; @r{the following prompt appears,} | |
3e01fd9d RS |
1340 | ;; @r{with an empty minibuffer:} |
1341 | @end group | |
1342 | ||
1343 | @group | |
1344 | ---------- Buffer: minibuffer ---------- | |
177c0ea7 | 1345 | Do you really want to remove everything? (yes or no) |
3e01fd9d RS |
1346 | ---------- Buffer: minibuffer ---------- |
1347 | @end group | |
1348 | @end smallexample | |
1349 | ||
1350 | @noindent | |
1351 | If the user first types @kbd{y @key{RET}}, which is invalid because this | |
1352 | function demands the entire word @samp{yes}, it responds by displaying | |
1353 | these prompts, with a brief pause between them: | |
1354 | ||
1355 | @smallexample | |
1356 | @group | |
1357 | ---------- Buffer: minibuffer ---------- | |
1358 | Please answer yes or no. | |
1359 | Do you really want to remove everything? (yes or no) | |
1360 | ---------- Buffer: minibuffer ---------- | |
1361 | @end group | |
1362 | @end smallexample | |
1363 | @end defun | |
1364 | ||
1365 | @node Multiple Queries | |
1366 | @section Asking Multiple Y-or-N Questions | |
1367 | ||
793da230 RS |
1368 | When you have a series of similar questions to ask, such as ``Do you |
1369 | want to save this buffer'' for each buffer in turn, you should use | |
1370 | @code{map-y-or-n-p} to ask the collection of questions, rather than | |
1371 | asking each question individually. This gives the user certain | |
1372 | convenient facilities such as the ability to answer the whole series at | |
1373 | once. | |
1374 | ||
2468d0c0 | 1375 | @defun map-y-or-n-p prompter actor list &optional help action-alist no-cursor-in-echo-area |
f9f59935 RS |
1376 | This function asks the user a series of questions, reading a |
1377 | single-character answer in the echo area for each one. | |
3e01fd9d RS |
1378 | |
1379 | The value of @var{list} specifies the objects to ask questions about. | |
1380 | It should be either a list of objects or a generator function. If it is | |
1381 | a function, it should expect no arguments, and should return either the | |
1382 | next object to ask about, or @code{nil} meaning stop asking questions. | |
1383 | ||
1384 | The argument @var{prompter} specifies how to ask each question. If | |
1385 | @var{prompter} is a string, the question text is computed like this: | |
1386 | ||
1387 | @example | |
1388 | (format @var{prompter} @var{object}) | |
1389 | @end example | |
1390 | ||
1391 | @noindent | |
1392 | where @var{object} is the next object to ask about (as obtained from | |
1393 | @var{list}). | |
1394 | ||
1395 | If not a string, @var{prompter} should be a function of one argument | |
63ff95ee MW |
1396 | (the next object to ask about) and should return the question text. If |
1397 | the value is a string, that is the question to ask the user. The | |
1398 | function can also return @code{t} meaning do act on this object (and | |
1399 | don't ask the user), or @code{nil} meaning ignore this object (and don't | |
1400 | ask the user). | |
3e01fd9d RS |
1401 | |
1402 | The argument @var{actor} says how to act on the answers that the user | |
1403 | gives. It should be a function of one argument, and it is called with | |
1404 | each object that the user says yes for. Its argument is always an | |
1405 | object obtained from @var{list}. | |
1406 | ||
1407 | If the argument @var{help} is given, it should be a list of this form: | |
1408 | ||
1409 | @example | |
1410 | (@var{singular} @var{plural} @var{action}) | |
1411 | @end example | |
1412 | ||
1413 | @noindent | |
1414 | where @var{singular} is a string containing a singular noun that | |
1415 | describes the objects conceptually being acted on, @var{plural} is the | |
1416 | corresponding plural noun, and @var{action} is a transitive verb | |
1417 | describing what @var{actor} does. | |
1418 | ||
1419 | If you don't specify @var{help}, the default is @code{("object" | |
1420 | "objects" "act on")}. | |
1421 | ||
1422 | Each time a question is asked, the user may enter @kbd{y}, @kbd{Y}, or | |
1423 | @key{SPC} to act on that object; @kbd{n}, @kbd{N}, or @key{DEL} to skip | |
1424 | that object; @kbd{!} to act on all following objects; @key{ESC} or | |
1425 | @kbd{q} to exit (skip all following objects); @kbd{.} (period) to act on | |
1426 | the current object and then exit; or @kbd{C-h} to get help. These are | |
1427 | the same answers that @code{query-replace} accepts. The keymap | |
1428 | @code{query-replace-map} defines their meaning for @code{map-y-or-n-p} | |
1429 | as well as for @code{query-replace}; see @ref{Search and Replace}. | |
1430 | ||
1431 | You can use @var{action-alist} to specify additional possible answers | |
1432 | and what they mean. It is an alist of elements of the form | |
1433 | @code{(@var{char} @var{function} @var{help})}, each of which defines one | |
1434 | additional answer. In this element, @var{char} is a character (the | |
1435 | answer); @var{function} is a function of one argument (an object from | |
1436 | @var{list}); @var{help} is a string. | |
1437 | ||
1438 | When the user responds with @var{char}, @code{map-y-or-n-p} calls | |
1439 | @var{function}. If it returns non-@code{nil}, the object is considered | |
1440 | ``acted upon'', and @code{map-y-or-n-p} advances to the next object in | |
1441 | @var{list}. If it returns @code{nil}, the prompt is repeated for the | |
1442 | same object. | |
1443 | ||
2468d0c0 DL |
1444 | Normally, @code{map-y-or-n-p} binds @code{cursor-in-echo-area} while |
1445 | prompting. But if @var{no-cursor-in-echo-area} is non-@code{nil}, it | |
1446 | does not do that. | |
1447 | ||
3e099569 RS |
1448 | If @code{map-y-or-n-p} is called in a command that was invoked using the |
1449 | mouse---more precisely, if @code{last-nonmenu-event} (@pxref{Command | |
1450 | Loop Info}) is either @code{nil} or a list---then it uses a dialog box | |
1451 | or pop-up menu to ask the question. In this case, it does not use | |
1452 | keyboard input or the echo area. You can force use of the mouse or use | |
1453 | of keyboard input by binding @code{last-nonmenu-event} to a suitable | |
1454 | value around the call. | |
1455 | ||
3e01fd9d RS |
1456 | The return value of @code{map-y-or-n-p} is the number of objects acted on. |
1457 | @end defun | |
1458 | ||
e75ecfec KH |
1459 | @node Reading a Password |
1460 | @section Reading a Password | |
1461 | @cindex passwords, reading | |
1462 | ||
1463 | To read a password to pass to another program, you can use the | |
1464 | function @code{read-passwd}. | |
1465 | ||
e75ecfec KH |
1466 | @defun read-passwd prompt &optional confirm default |
1467 | This function reads a password, prompting with @var{prompt}. It does | |
1468 | not echo the password as the user types it; instead, it echoes @samp{.} | |
1469 | for each character in the password. | |
1470 | ||
1471 | The optional argument @var{confirm}, if non-@code{nil}, says to read the | |
1472 | password twice and insist it must be the same both times. If it isn't | |
1473 | the same, the user has to type it over and over until the last two | |
1474 | times match. | |
1475 | ||
1476 | The optional argument @var{default} specifies the default password to | |
1477 | return if the user enters empty input. If @var{default} is @code{nil}, | |
1478 | then @code{read-passwd} returns the null string in that case. | |
1479 | @end defun | |
1480 | ||
3e01fd9d | 1481 | @node Minibuffer Misc |
3e01fd9d RS |
1482 | @section Minibuffer Miscellany |
1483 | ||
1484 | This section describes some basic functions and variables related to | |
1485 | minibuffers. | |
1486 | ||
1487 | @deffn Command exit-minibuffer | |
1488 | This command exits the active minibuffer. It is normally bound to | |
1489 | keys in minibuffer local keymaps. | |
1490 | @end deffn | |
1491 | ||
1492 | @deffn Command self-insert-and-exit | |
1493 | This command exits the active minibuffer after inserting the last | |
1494 | character typed on the keyboard (found in @code{last-command-char}; | |
1495 | @pxref{Command Loop Info}). | |
1496 | @end deffn | |
1497 | ||
1498 | @deffn Command previous-history-element n | |
1499 | This command replaces the minibuffer contents with the value of the | |
1500 | @var{n}th previous (older) history element. | |
1501 | @end deffn | |
1502 | ||
1503 | @deffn Command next-history-element n | |
1504 | This command replaces the minibuffer contents with the value of the | |
1505 | @var{n}th more recent history element. | |
1506 | @end deffn | |
1507 | ||
2468d0c0 | 1508 | @deffn Command previous-matching-history-element pattern n |
3e01fd9d | 1509 | This command replaces the minibuffer contents with the value of the |
2468d0c0 DL |
1510 | @var{n}th previous (older) history element that matches @var{pattern} (a |
1511 | regular expression). | |
3e01fd9d RS |
1512 | @end deffn |
1513 | ||
2468d0c0 DL |
1514 | @deffn Command next-matching-history-element pattern n |
1515 | This command replaces the minibuffer contents with the value of the | |
1516 | @var{n}th next (newer) history element that matches @var{pattern} (a | |
1517 | regular expression). | |
3e01fd9d RS |
1518 | @end deffn |
1519 | ||
bfe721d1 KH |
1520 | @defun minibuffer-prompt |
1521 | This function returns the prompt string of the currently active | |
1522 | minibuffer. If no minibuffer is active, it returns @code{nil}. | |
1523 | @end defun | |
1524 | ||
2468d0c0 | 1525 | @defun minibuffer-prompt-end |
b3b044f2 | 1526 | @tindex minibuffer-prompt-end |
8241495d RS |
1527 | This function, available starting in Emacs 21, returns the current |
1528 | position of the end of the minibuffer prompt, if a minibuffer is | |
b3b044f2 MB |
1529 | current. Otherwise, it returns the minimum valid buffer position. |
1530 | @end defun | |
1531 | ||
1532 | @defun minibuffer-contents | |
1533 | @tindex minibuffer-contents | |
1534 | This function, available starting in Emacs 21, returns the editable | |
1535 | contents of the minibuffer (that is, everything except the prompt) as | |
1536 | a string, if a minibuffer is current. Otherwise, it returns the | |
1537 | entire contents of the current buffer. | |
1538 | @end defun | |
1539 | ||
1540 | @defun minibuffer-contents-no-properties | |
1541 | @tindex minibuffer-contents-no-properties | |
1542 | This is like @code{minibuffer-contents}, except that it does not copy text | |
1543 | properties, just the characters themselves. @xref{Text Properties}. | |
1544 | @end defun | |
1545 | ||
1546 | @defun delete-minibuffer-contents | |
1547 | @tindex delete-minibuffer-contents | |
1548 | This function, available starting in Emacs 21, erases the editable | |
1549 | contents of the minibuffer (that is, everything except the prompt), if | |
1550 | a minibuffer is current. Otherwise, it erases the entire buffer. | |
8241495d RS |
1551 | @end defun |
1552 | ||
42d9d13a | 1553 | @defun minibuffer-prompt-width |
8241495d RS |
1554 | This function returns the current display-width of the minibuffer |
1555 | prompt, if a minibuffer is current. Otherwise, it returns zero. | |
bfe721d1 KH |
1556 | @end defun |
1557 | ||
3e01fd9d RS |
1558 | @defvar minibuffer-setup-hook |
1559 | This is a normal hook that is run whenever the minibuffer is entered. | |
793da230 RS |
1560 | @xref{Hooks}. |
1561 | @end defvar | |
1562 | ||
612b4d5c | 1563 | @defvar minibuffer-exit-hook |
793da230 RS |
1564 | This is a normal hook that is run whenever the minibuffer is exited. |
1565 | @xref{Hooks}. | |
3e01fd9d RS |
1566 | @end defvar |
1567 | ||
1568 | @defvar minibuffer-help-form | |
1569 | The current value of this variable is used to rebind @code{help-form} | |
1570 | locally inside the minibuffer (@pxref{Help Functions}). | |
1571 | @end defvar | |
1572 | ||
22697dac KH |
1573 | @defun active-minibuffer-window |
1574 | This function returns the currently active minibuffer window, or | |
1575 | @code{nil} if none is currently active. | |
1576 | @end defun | |
1577 | ||
3e01fd9d | 1578 | @defun minibuffer-window &optional frame |
22697dac KH |
1579 | This function returns the minibuffer window used for frame @var{frame}. |
1580 | If @var{frame} is @code{nil}, that stands for the current frame. Note | |
1581 | that the minibuffer window used by a frame need not be part of that | |
1582 | frame---a frame that has no minibuffer of its own necessarily uses some | |
1583 | other frame's minibuffer window. | |
3e01fd9d RS |
1584 | @end defun |
1585 | ||
1586 | @c Emacs 19 feature | |
1587 | @defun window-minibuffer-p window | |
1588 | This function returns non-@code{nil} if @var{window} is a minibuffer window. | |
1589 | @end defun | |
1590 | ||
1591 | It is not correct to determine whether a given window is a minibuffer by | |
1592 | comparing it with the result of @code{(minibuffer-window)}, because | |
1593 | there can be more than one minibuffer window if there is more than one | |
1594 | frame. | |
1595 | ||
1596 | @defun minibuffer-window-active-p window | |
1597 | This function returns non-@code{nil} if @var{window}, assumed to be | |
1598 | a minibuffer window, is currently active. | |
1599 | @end defun | |
1600 | ||
1601 | @defvar minibuffer-scroll-window | |
1602 | If the value of this variable is non-@code{nil}, it should be a window | |
1603 | object. When the function @code{scroll-other-window} is called in the | |
1604 | minibuffer, it scrolls this window. | |
1605 | @end defvar | |
1606 | ||
1607 | Finally, some functions and variables deal with recursive minibuffers | |
1608 | (@pxref{Recursive Editing}): | |
1609 | ||
1610 | @defun minibuffer-depth | |
1611 | This function returns the current depth of activations of the | |
1612 | minibuffer, a nonnegative integer. If no minibuffers are active, it | |
1613 | returns zero. | |
1614 | @end defun | |
1615 | ||
1616 | @defopt enable-recursive-minibuffers | |
1617 | If this variable is non-@code{nil}, you can invoke commands (such as | |
969fe9b5 RS |
1618 | @code{find-file}) that use minibuffers even while the minibuffer window |
1619 | is active. Such invocation produces a recursive editing level for a new | |
3e01fd9d RS |
1620 | minibuffer. The outer-level minibuffer is invisible while you are |
1621 | editing the inner one. | |
1622 | ||
969fe9b5 RS |
1623 | If this variable is @code{nil}, you cannot invoke minibuffer |
1624 | commands when the minibuffer window is active, not even if you switch to | |
1625 | another window to do it. | |
3e01fd9d RS |
1626 | @end defopt |
1627 | ||
1628 | @c Emacs 19 feature | |
1629 | If a command name has a property @code{enable-recursive-minibuffers} | |
793da230 | 1630 | that is non-@code{nil}, then the command can use the minibuffer to read |
3e01fd9d | 1631 | arguments even if it is invoked from the minibuffer. The minibuffer |
bfe721d1 KH |
1632 | command @code{next-matching-history-element} (normally @kbd{M-s} in the |
1633 | minibuffer) uses this feature. |