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