Commit | Line | Data |
---|---|---|
b8d4c8d0 GM |
1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
acaf905b | 3 | @c Copyright (C) 1990-1995, 1998-1999, 2001-2012 |
d24880de | 4 | @c Free Software Foundation, Inc. |
b8d4c8d0 | 5 | @c See the file elisp.texi for copying conditions. |
b8d4c8d0 GM |
6 | @node Minibuffers, Command Loop, Read and Print, Top |
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 | |
13 | read arguments more complicated than the single numeric prefix | |
14 | argument. These arguments include file names, buffer names, and | |
15 | command names (as in @kbd{M-x}). The minibuffer is displayed on the | |
16 | bottom line of the frame, in the same place as the echo area | |
17 | (@pxref{The Echo Area}), but only while it is in use for reading an | |
18 | argument. | |
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. | |
d24880de GM |
24 | * Minibuffer History:: Recording previous minibuffer inputs |
25 | so the user can reuse them. | |
b8d4c8d0 GM |
26 | * Initial Input:: Specifying initial contents for the minibuffer. |
27 | * Completion:: How to invoke and customize completion. | |
28 | * Yes-or-No Queries:: Asking a question with a simple answer. | |
d24880de GM |
29 | * Multiple Queries:: Asking a series of similar questions. |
30 | * Reading a Password:: Reading a password from the terminal. | |
b8d4c8d0 | 31 | * Minibuffer Commands:: Commands used as key bindings in minibuffers. |
b8d4c8d0 | 32 | * Minibuffer Windows:: Operating on the special minibuffer windows. |
c0ea08d2 | 33 | * Minibuffer Contents:: How such commands access the minibuffer text. |
b8d4c8d0 GM |
34 | * Recursive Mini:: Whether recursive entry to minibuffer is allowed. |
35 | * Minibuffer Misc:: Various customization hooks and variables. | |
36 | @end menu | |
37 | ||
38 | @node Intro to Minibuffers | |
39 | @section Introduction to Minibuffers | |
40 | ||
41 | In most ways, a minibuffer is a normal Emacs buffer. Most operations | |
42 | @emph{within} a buffer, such as editing commands, work normally in a | |
43 | minibuffer. However, many operations for managing buffers do not apply | |
44 | to minibuffers. The name of a minibuffer always has the form @w{@samp{ | |
45 | *Minibuf-@var{number}*}}, and it cannot be changed. Minibuffers are | |
46 | displayed only in special windows used only for minibuffers; these | |
47 | windows always appear at the bottom of a frame. (Sometimes frames have | |
48 | no minibuffer window, and sometimes a special kind of frame contains | |
49 | nothing but a minibuffer window; see @ref{Minibuffers and Frames}.) | |
50 | ||
51 | The text in the minibuffer always starts with the @dfn{prompt string}, | |
52 | the text that was specified by the program that is using the minibuffer | |
53 | to tell the user what sort of input to type. This text is marked | |
54 | read-only so you won't accidentally delete or change it. It is also | |
55 | marked as a field (@pxref{Fields}), so that certain motion functions, | |
56 | including @code{beginning-of-line}, @code{forward-word}, | |
57 | @code{forward-sentence}, and @code{forward-paragraph}, stop at the | |
a560da7e | 58 | boundary between the prompt and the actual text. |
b8d4c8d0 | 59 | |
9c51bbaa | 60 | @c See http://debbugs.gnu.org/11276 |
b8d4c8d0 | 61 | The minibuffer's window is normally a single line; it grows |
9c51bbaa GM |
62 | automatically if the contents require more space. Whilst it is |
63 | active, you can explicitly resize it temporarily with the window | |
64 | sizing commands; it reverts to its normal size when the minibuffer is | |
65 | exited. When the minibuffer is not active, you can resize it | |
a560da7e | 66 | permanently by using the window sizing commands in the frame's other |
9c51bbaa GM |
67 | window, or dragging the mode line with the mouse. (Due to details of |
68 | the current implementation, for this to work @code{resize-mini-windows} | |
69 | must be @code{nil}.) If the frame contains just a minibuffer, you can | |
70 | change the minibuffer's size by changing the frame's size. | |
b8d4c8d0 GM |
71 | |
72 | Use of the minibuffer reads input events, and that alters the values | |
73 | of variables such as @code{this-command} and @code{last-command} | |
74 | (@pxref{Command Loop Info}). Your program should bind them around the | |
75 | code that uses the minibuffer, if you do not want that to change them. | |
76 | ||
a560da7e | 77 | Under some circumstances, a command can use a minibuffer even if |
9d2754f5 | 78 | there is an active minibuffer; such a minibuffer is called a |
a560da7e | 79 | @dfn{recursive minibuffer}. The first minibuffer is named |
9d2754f5 | 80 | @w{@samp{ *Minibuf-1*}}. Recursive minibuffers are named by |
a560da7e CY |
81 | incrementing the number at the end of the name. (The names begin with |
82 | a space so that they won't show up in normal buffer lists.) Of | |
83 | several recursive minibuffers, the innermost (or most recently | |
84 | entered) is the active minibuffer. We usually call this ``the'' | |
85 | minibuffer. You can permit or forbid recursive minibuffers by setting | |
86 | the variable @code{enable-recursive-minibuffers}, or by putting | |
11625308 | 87 | properties of that name on command symbols (@xref{Recursive Mini}.) |
b8d4c8d0 GM |
88 | |
89 | Like other buffers, a minibuffer uses a local keymap | |
90 | (@pxref{Keymaps}) to specify special key bindings. The function that | |
91 | invokes the minibuffer also sets up its local map according to the job | |
92 | to be done. @xref{Text from Minibuffer}, for the non-completion | |
93 | minibuffer local maps. @xref{Completion Commands}, for the minibuffer | |
94 | local maps for completion. | |
95 | ||
9d2754f5 | 96 | @cindex inactive minibuffer |
78c1f490 | 97 | When a minibuffer is inactive, its major mode is |
9d2754f5 GM |
98 | @code{minibuffer-inactive-mode}, with keymap |
99 | @code{minibuffer-inactive-mode-map}. This is only really useful if | |
100 | the minibuffer is in a separate frame. @xref{Minibuffers and Frames}. | |
101 | ||
b8d4c8d0 GM |
102 | When Emacs is running in batch mode, any request to read from the |
103 | minibuffer actually reads a line from the standard input descriptor that | |
104 | was supplied when Emacs was started. | |
105 | ||
106 | @node Text from Minibuffer | |
107 | @section Reading Text Strings with the Minibuffer | |
108 | ||
a560da7e CY |
109 | The most basic primitive for minibuffer input is |
110 | @code{read-from-minibuffer}, which can be used to read either a string | |
111 | or a Lisp object in textual form. The function @code{read-regexp} is | |
112 | used for reading regular expressions (@pxref{Regular Expressions}), | |
113 | which are a special kind of string. There are also specialized | |
114 | functions for reading commands, variables, file names, etc.@: | |
115 | (@pxref{Completion}). | |
b8d4c8d0 GM |
116 | |
117 | In most cases, you should not call minibuffer input functions in the | |
118 | middle of a Lisp function. Instead, do all minibuffer input as part of | |
119 | reading the arguments for a command, in the @code{interactive} | |
120 | specification. @xref{Defining Commands}. | |
121 | ||
9d2754f5 | 122 | @defun read-from-minibuffer prompt &optional initial keymap read history default inherit-input-method |
a560da7e | 123 | This function is the most general way to get input from the |
b8d4c8d0 GM |
124 | minibuffer. By default, it accepts arbitrary text and returns it as a |
125 | string; however, if @var{read} is non-@code{nil}, then it uses | |
126 | @code{read} to convert the text into a Lisp object (@pxref{Input | |
127 | Functions}). | |
128 | ||
129 | The first thing this function does is to activate a minibuffer and | |
9d2754f5 GM |
130 | display it with @var{prompt} (which must be a string) as the |
131 | prompt. Then the user can edit text in the minibuffer. | |
b8d4c8d0 GM |
132 | |
133 | When the user types a command to exit the minibuffer, | |
134 | @code{read-from-minibuffer} constructs the return value from the text in | |
135 | the minibuffer. Normally it returns a string containing that text. | |
136 | However, if @var{read} is non-@code{nil}, @code{read-from-minibuffer} | |
137 | reads the text and returns the resulting Lisp object, unevaluated. | |
138 | (@xref{Input Functions}, for information about reading.) | |
139 | ||
c1d2409c RS |
140 | The argument @var{default} specifies default values to make available |
141 | through the history commands. It should be a string, a list of | |
142 | strings, or @code{nil}. The string or strings become the minibuffer's | |
9d2754f5 | 143 | ``future history'', available to the user with @kbd{M-n}. |
c1d2409c | 144 | |
63b4387f JL |
145 | If @var{read} is non-@code{nil}, then @var{default} is also used |
146 | as the input to @code{read}, if the user enters empty input. | |
147 | If @var{default} is a list of strings, the first string is used as the input. | |
148 | If @var{default} is @code{nil}, empty input results in an @code{end-of-file} error. | |
149 | However, in the usual case (where @var{read} is @code{nil}), | |
150 | @code{read-from-minibuffer} ignores @var{default} when the user enters | |
151 | empty input and returns an empty string, @code{""}. In this respect, | |
152 | it differs from all the other minibuffer input functions in this chapter. | |
b8d4c8d0 GM |
153 | |
154 | If @var{keymap} is non-@code{nil}, that keymap is the local keymap to | |
155 | use in the minibuffer. If @var{keymap} is omitted or @code{nil}, the | |
156 | value of @code{minibuffer-local-map} is used as the keymap. Specifying | |
157 | a keymap is the most important way to customize the minibuffer for | |
158 | various applications such as completion. | |
159 | ||
9d2754f5 | 160 | The argument @var{history} specifies a history list variable to use |
b8d4c8d0 | 161 | for saving the input and for history commands used in the minibuffer. |
9d2754f5 GM |
162 | It defaults to @code{minibuffer-history}. You can optionally specify |
163 | a starting position in the history list as well. @xref{Minibuffer History}. | |
b8d4c8d0 GM |
164 | |
165 | If the variable @code{minibuffer-allow-text-properties} is | |
9d2754f5 | 166 | non-@code{nil}, then the string that is returned includes whatever text |
b8d4c8d0 GM |
167 | properties were present in the minibuffer. Otherwise all the text |
168 | properties are stripped when the value is returned. | |
169 | ||
170 | If the argument @var{inherit-input-method} is non-@code{nil}, then the | |
171 | minibuffer inherits the current input method (@pxref{Input Methods}) and | |
172 | the setting of @code{enable-multibyte-characters} (@pxref{Text | |
173 | Representations}) from whichever buffer was current before entering the | |
174 | minibuffer. | |
175 | ||
9d2754f5 | 176 | Use of @var{initial} is mostly deprecated; we recommend using |
b8d4c8d0 | 177 | a non-@code{nil} value only in conjunction with specifying a cons cell |
9d2754f5 | 178 | for @var{history}. @xref{Initial Input}. |
b8d4c8d0 GM |
179 | @end defun |
180 | ||
181 | @defun read-string prompt &optional initial history default inherit-input-method | |
182 | This function reads a string from the minibuffer and returns it. The | |
183 | arguments @var{prompt}, @var{initial}, @var{history} and | |
184 | @var{inherit-input-method} are used as in @code{read-from-minibuffer}. | |
185 | The keymap used is @code{minibuffer-local-map}. | |
186 | ||
187 | The optional argument @var{default} is used as in | |
188 | @code{read-from-minibuffer}, except that, if non-@code{nil}, it also | |
189 | specifies a default value to return if the user enters null input. As | |
c1d2409c | 190 | in @code{read-from-minibuffer} it should be a string, a list of |
9d2754f5 | 191 | strings, or @code{nil}, which is equivalent to an empty string. When |
c1d2409c RS |
192 | @var{default} is a string, that string is the default value. When it |
193 | is a list of strings, the first string is the default value. (All | |
194 | these strings are available to the user in the ``future minibuffer | |
9d2754f5 | 195 | history''.) |
c1d2409c RS |
196 | |
197 | This function works by calling the | |
b8d4c8d0 GM |
198 | @code{read-from-minibuffer} function: |
199 | ||
200 | @smallexample | |
201 | @group | |
202 | (read-string @var{prompt} @var{initial} @var{history} @var{default} @var{inherit}) | |
203 | @equiv{} | |
204 | (let ((value | |
205 | (read-from-minibuffer @var{prompt} @var{initial} nil nil | |
206 | @var{history} @var{default} @var{inherit}))) | |
207 | (if (and (equal value "") @var{default}) | |
c066bafa | 208 | (if (consp @var{default}) (car @var{default}) @var{default}) |
b8d4c8d0 GM |
209 | value)) |
210 | @end group | |
211 | @end smallexample | |
212 | @end defun | |
213 | ||
9d2754f5 | 214 | @defun read-regexp prompt &optional default |
6d4913f0 EZ |
215 | This function reads a regular expression as a string from the |
216 | minibuffer and returns it. The argument @var{prompt} is used as in | |
217 | @code{read-from-minibuffer}. The keymap used is | |
218 | @code{minibuffer-local-map}, and @code{regexp-history} is used as the | |
219 | history list (@pxref{Minibuffer History, regexp-history}). | |
220 | ||
9d2754f5 | 221 | The optional argument @var{default} specifies a default value to |
2ee797be | 222 | return if the user enters null input; it should be a string, or |
9d2754f5 | 223 | @code{nil}, which is equivalent to an empty string. |
2ee797be EZ |
224 | |
225 | In addition, @code{read-regexp} collects a few useful candidates for | |
226 | input and passes them to @code{read-from-minibuffer}, to make them | |
227 | available to the user as the ``future minibuffer history list'' | |
228 | (@pxref{Minibuffer History, future list,, emacs, The GNU Emacs | |
229 | Manual}). These candidates are: | |
6d4913f0 EZ |
230 | |
231 | @itemize @minus | |
232 | @item | |
56b00ec7 | 233 | The word or symbol at point. |
6d4913f0 EZ |
234 | @item |
235 | The last regexp used in an incremental search. | |
236 | @item | |
237 | The last string used in an incremental search. | |
238 | @item | |
239 | The last string or pattern used in query-replace commands. | |
240 | @end itemize | |
241 | ||
242 | This function works by calling the @code{read-from-minibuffer} | |
243 | function, after computing the list of defaults as described above. | |
244 | @end defun | |
245 | ||
b8d4c8d0 | 246 | @defvar minibuffer-allow-text-properties |
9d2754f5 GM |
247 | If this variable is @code{nil}, then @code{read-from-minibuffer} |
248 | and @code{read-string} strip all text properties from the minibuffer | |
249 | input before returning it. However, | |
b8d4c8d0 GM |
250 | @code{read-no-blanks-input} (see below), as well as |
251 | @code{read-minibuffer} and related functions (@pxref{Object from | |
252 | Minibuffer,, Reading Lisp Objects With the Minibuffer}), and all | |
253 | functions that do minibuffer input with completion, discard text | |
254 | properties unconditionally, regardless of the value of this variable. | |
255 | @end defvar | |
256 | ||
257 | @defvar minibuffer-local-map | |
258 | This | |
259 | @anchor{Definition of minibuffer-local-map} | |
260 | @c avoid page break at anchor; work around Texinfo deficiency | |
261 | is the default local keymap for reading from the minibuffer. By | |
262 | default, it makes the following bindings: | |
263 | ||
264 | @table @asis | |
265 | @item @kbd{C-j} | |
266 | @code{exit-minibuffer} | |
267 | ||
268 | @item @key{RET} | |
269 | @code{exit-minibuffer} | |
270 | ||
271 | @item @kbd{C-g} | |
272 | @code{abort-recursive-edit} | |
273 | ||
274 | @item @kbd{M-n} | |
275 | @itemx @key{DOWN} | |
276 | @code{next-history-element} | |
277 | ||
278 | @item @kbd{M-p} | |
279 | @itemx @key{UP} | |
280 | @code{previous-history-element} | |
281 | ||
282 | @item @kbd{M-s} | |
283 | @code{next-matching-history-element} | |
284 | ||
285 | @item @kbd{M-r} | |
286 | @code{previous-matching-history-element} | |
9d2754f5 GM |
287 | |
288 | @ignore | |
289 | @c Does not seem worth/appropriate mentioning. | |
290 | @item @kbd{C-@key{TAB}} | |
291 | @code{file-cache-minibuffer-complete} | |
292 | @end ignore | |
b8d4c8d0 GM |
293 | @end table |
294 | @end defvar | |
295 | ||
296 | @c In version 18, initial is required | |
297 | @c Emacs 19 feature | |
298 | @defun read-no-blanks-input prompt &optional initial inherit-input-method | |
299 | This function reads a string from the minibuffer, but does not allow | |
300 | whitespace characters as part of the input: instead, those characters | |
301 | terminate the input. The arguments @var{prompt}, @var{initial}, and | |
302 | @var{inherit-input-method} are used as in @code{read-from-minibuffer}. | |
303 | ||
304 | This is a simplified interface to the @code{read-from-minibuffer} | |
305 | function, and passes the value of the @code{minibuffer-local-ns-map} | |
306 | keymap as the @var{keymap} argument for that function. Since the keymap | |
307 | @code{minibuffer-local-ns-map} does not rebind @kbd{C-q}, it @emph{is} | |
308 | possible to put a space into the string, by quoting it. | |
309 | ||
310 | This function discards text properties, regardless of the value of | |
311 | @code{minibuffer-allow-text-properties}. | |
312 | ||
313 | @smallexample | |
314 | @group | |
315 | (read-no-blanks-input @var{prompt} @var{initial}) | |
316 | @equiv{} | |
317 | (let (minibuffer-allow-text-properties) | |
318 | (read-from-minibuffer @var{prompt} @var{initial} minibuffer-local-ns-map)) | |
319 | @end group | |
320 | @end smallexample | |
321 | @end defun | |
322 | ||
9d2754f5 GM |
323 | @c Slightly unfortunate name, suggesting it might be related to the |
324 | @c Nextstep port... | |
b8d4c8d0 GM |
325 | @defvar minibuffer-local-ns-map |
326 | This built-in variable is the keymap used as the minibuffer local keymap | |
327 | in the function @code{read-no-blanks-input}. By default, it makes the | |
328 | following bindings, in addition to those of @code{minibuffer-local-map}: | |
329 | ||
330 | @table @asis | |
331 | @item @key{SPC} | |
332 | @cindex @key{SPC} in minibuffer | |
333 | @code{exit-minibuffer} | |
334 | ||
335 | @item @key{TAB} | |
336 | @cindex @key{TAB} in minibuffer | |
337 | @code{exit-minibuffer} | |
338 | ||
339 | @item @kbd{?} | |
340 | @cindex @kbd{?} in minibuffer | |
341 | @code{self-insert-and-exit} | |
342 | @end table | |
343 | @end defvar | |
344 | ||
345 | @node Object from Minibuffer | |
346 | @section Reading Lisp Objects with the Minibuffer | |
347 | ||
348 | This section describes functions for reading Lisp objects with the | |
349 | minibuffer. | |
350 | ||
351 | @defun read-minibuffer prompt &optional initial | |
352 | This function reads a Lisp object using the minibuffer, and returns it | |
353 | without evaluating it. The arguments @var{prompt} and @var{initial} are | |
354 | used as in @code{read-from-minibuffer}. | |
355 | ||
356 | This is a simplified interface to the | |
357 | @code{read-from-minibuffer} function: | |
358 | ||
359 | @smallexample | |
360 | @group | |
361 | (read-minibuffer @var{prompt} @var{initial}) | |
362 | @equiv{} | |
363 | (let (minibuffer-allow-text-properties) | |
364 | (read-from-minibuffer @var{prompt} @var{initial} nil t)) | |
365 | @end group | |
366 | @end smallexample | |
367 | ||
368 | Here is an example in which we supply the string @code{"(testing)"} as | |
369 | initial input: | |
370 | ||
371 | @smallexample | |
372 | @group | |
373 | (read-minibuffer | |
374 | "Enter an expression: " (format "%s" '(testing))) | |
375 | ||
376 | ;; @r{Here is how the minibuffer is displayed:} | |
377 | @end group | |
378 | ||
379 | @group | |
380 | ---------- Buffer: Minibuffer ---------- | |
381 | Enter an expression: (testing)@point{} | |
382 | ---------- Buffer: Minibuffer ---------- | |
383 | @end group | |
384 | @end smallexample | |
385 | ||
386 | @noindent | |
387 | The user can type @key{RET} immediately to use the initial input as a | |
388 | default, or can edit the input. | |
389 | @end defun | |
390 | ||
391 | @defun eval-minibuffer prompt &optional initial | |
392 | This function reads a Lisp expression using the minibuffer, evaluates | |
393 | it, then returns the result. The arguments @var{prompt} and | |
394 | @var{initial} are used as in @code{read-from-minibuffer}. | |
395 | ||
396 | This function simply evaluates the result of a call to | |
397 | @code{read-minibuffer}: | |
398 | ||
399 | @smallexample | |
400 | @group | |
401 | (eval-minibuffer @var{prompt} @var{initial}) | |
402 | @equiv{} | |
403 | (eval (read-minibuffer @var{prompt} @var{initial})) | |
404 | @end group | |
405 | @end smallexample | |
406 | @end defun | |
407 | ||
408 | @defun edit-and-eval-command prompt form | |
c0ea08d2 GM |
409 | This function reads a Lisp expression in the minibuffer, evaluates it, |
410 | then returns the result. The difference between this command and | |
b8d4c8d0 GM |
411 | @code{eval-minibuffer} is that here the initial @var{form} is not |
412 | optional and it is treated as a Lisp object to be converted to printed | |
413 | representation rather than as a string of text. It is printed with | |
414 | @code{prin1}, so if it is a string, double-quote characters (@samp{"}) | |
415 | appear in the initial text. @xref{Output Functions}. | |
416 | ||
b8d4c8d0 | 417 | In the following example, we offer the user an expression with initial |
c0ea08d2 | 418 | text that is already a valid form: |
b8d4c8d0 GM |
419 | |
420 | @smallexample | |
421 | @group | |
422 | (edit-and-eval-command "Please edit: " '(forward-word 1)) | |
423 | ||
424 | ;; @r{After evaluation of the preceding expression,} | |
425 | ;; @r{the following appears in the minibuffer:} | |
426 | @end group | |
427 | ||
428 | @group | |
429 | ---------- Buffer: Minibuffer ---------- | |
430 | Please edit: (forward-word 1)@point{} | |
431 | ---------- Buffer: Minibuffer ---------- | |
432 | @end group | |
433 | @end smallexample | |
434 | ||
435 | @noindent | |
436 | Typing @key{RET} right away would exit the minibuffer and evaluate the | |
437 | expression, thus moving point forward one word. | |
b8d4c8d0 GM |
438 | @end defun |
439 | ||
440 | @node Minibuffer History | |
441 | @section Minibuffer History | |
442 | @cindex minibuffer history | |
443 | @cindex history list | |
444 | ||
b923f7a9 CY |
445 | A @dfn{minibuffer history list} records previous minibuffer inputs |
446 | so the user can reuse them conveniently. It is a variable whose value | |
447 | is a list of strings (previous inputs), most recent first. | |
448 | ||
449 | There are many separate minibuffer history lists, used for different | |
450 | kinds of inputs. It's the Lisp programmer's job to specify the right | |
451 | history list for each use of the minibuffer. | |
452 | ||
9d2754f5 | 453 | You specify a minibuffer history list with the optional @var{history} |
b923f7a9 CY |
454 | argument to @code{read-from-minibuffer} or @code{completing-read}. |
455 | Here are the possible values for it: | |
b8d4c8d0 GM |
456 | |
457 | @table @asis | |
458 | @item @var{variable} | |
459 | Use @var{variable} (a symbol) as the history list. | |
460 | ||
461 | @item (@var{variable} . @var{startpos}) | |
462 | Use @var{variable} (a symbol) as the history list, and assume that the | |
463 | initial history position is @var{startpos} (a nonnegative integer). | |
464 | ||
465 | Specifying 0 for @var{startpos} is equivalent to just specifying the | |
466 | symbol @var{variable}. @code{previous-history-element} will display | |
467 | the most recent element of the history list in the minibuffer. If you | |
468 | specify a positive @var{startpos}, the minibuffer history functions | |
9d2754f5 | 469 | behave as if @code{(elt @var{variable} (1- @var{startpos}))} were the |
b8d4c8d0 GM |
470 | history element currently shown in the minibuffer. |
471 | ||
472 | For consistency, you should also specify that element of the history | |
473 | as the initial minibuffer contents, using the @var{initial} argument | |
474 | to the minibuffer input function (@pxref{Initial Input}). | |
475 | @end table | |
476 | ||
9d2754f5 | 477 | If you don't specify @var{history}, then the default history list |
b8d4c8d0 GM |
478 | @code{minibuffer-history} is used. For other standard history lists, |
479 | see below. You can also create your own history list variable; just | |
480 | initialize it to @code{nil} before the first use. | |
481 | ||
482 | Both @code{read-from-minibuffer} and @code{completing-read} add new | |
483 | elements to the history list automatically, and provide commands to | |
484 | allow the user to reuse items on the list. The only thing your program | |
485 | needs to do to use a history list is to initialize it and to pass its | |
486 | name to the input functions when you wish. But it is safe to modify the | |
487 | list by hand when the minibuffer input functions are not using it. | |
488 | ||
489 | Emacs functions that add a new element to a history list can also | |
490 | delete old elements if the list gets too long. The variable | |
491 | @code{history-length} specifies the maximum length for most history | |
492 | lists. To specify a different maximum length for a particular history | |
493 | list, put the length in the @code{history-length} property of the | |
494 | history list symbol. The variable @code{history-delete-duplicates} | |
495 | specifies whether to delete duplicates in history. | |
496 | ||
497 | @defun add-to-history history-var newelt &optional maxelt keep-all | |
498 | This function adds a new element @var{newelt}, if it isn't the empty | |
499 | string, to the history list stored in the variable @var{history-var}, | |
500 | and returns the updated history list. It limits the list length to | |
501 | the value of @var{maxelt} (if non-@code{nil}) or @code{history-length} | |
502 | (described below). The possible values of @var{maxelt} have the same | |
503 | meaning as the values of @code{history-length}. | |
504 | ||
505 | Normally, @code{add-to-history} removes duplicate members from the | |
506 | history list if @code{history-delete-duplicates} is non-@code{nil}. | |
507 | However, if @var{keep-all} is non-@code{nil}, that says not to remove | |
508 | duplicates, and to add @var{newelt} to the list even if it is empty. | |
509 | @end defun | |
510 | ||
511 | @defvar history-add-new-input | |
512 | If the value of this variable is @code{nil}, standard functions that | |
513 | read from the minibuffer don't add new elements to the history list. | |
514 | This lets Lisp programs explicitly manage input history by using | |
e68b393e | 515 | @code{add-to-history}. The default value is @code{t}. |
b8d4c8d0 GM |
516 | @end defvar |
517 | ||
01f17ae2 | 518 | @defopt history-length |
b8d4c8d0 GM |
519 | The value of this variable specifies the maximum length for all |
520 | history lists that don't specify their own maximum lengths. If the | |
da0bbbc4 | 521 | value is @code{t}, that means there is no maximum (don't delete old |
c0ea08d2 GM |
522 | elements). If a history list variable's symbol has a non-@code{nil} |
523 | @code{history-length} property, it overrides this variable for that | |
b8d4c8d0 | 524 | particular history list. |
01f17ae2 | 525 | @end defopt |
b8d4c8d0 | 526 | |
01f17ae2 | 527 | @defopt history-delete-duplicates |
b8d4c8d0 GM |
528 | If the value of this variable is @code{t}, that means when adding a |
529 | new history element, all previous identical elements are deleted. | |
01f17ae2 | 530 | @end defopt |
b8d4c8d0 GM |
531 | |
532 | Here are some of the standard minibuffer history list variables: | |
533 | ||
534 | @defvar minibuffer-history | |
535 | The default history list for minibuffer history input. | |
536 | @end defvar | |
537 | ||
538 | @defvar query-replace-history | |
539 | A history list for arguments to @code{query-replace} (and similar | |
540 | arguments to other commands). | |
541 | @end defvar | |
542 | ||
543 | @defvar file-name-history | |
544 | A history list for file-name arguments. | |
545 | @end defvar | |
546 | ||
547 | @defvar buffer-name-history | |
548 | A history list for buffer-name arguments. | |
549 | @end defvar | |
550 | ||
551 | @defvar regexp-history | |
552 | A history list for regular expression arguments. | |
553 | @end defvar | |
554 | ||
555 | @defvar extended-command-history | |
556 | A history list for arguments that are names of extended commands. | |
557 | @end defvar | |
558 | ||
559 | @defvar shell-command-history | |
560 | A history list for arguments that are shell commands. | |
561 | @end defvar | |
562 | ||
563 | @defvar read-expression-history | |
564 | A history list for arguments that are Lisp expressions to evaluate. | |
565 | @end defvar | |
566 | ||
c0ea08d2 GM |
567 | @defvar face-name-history |
568 | A history list for arguments that are faces. | |
569 | @end defvar | |
570 | ||
571 | @c Less common: coding-system-history, input-method-history, | |
572 | @c command-history, grep-history, grep-find-history, | |
573 | @c read-envvar-name-history, setenv-history, yes-or-no-p-history. | |
574 | ||
b8d4c8d0 GM |
575 | @node Initial Input |
576 | @section Initial Input | |
577 | ||
578 | Several of the functions for minibuffer input have an argument called | |
9d2754f5 | 579 | @var{initial}. This is a mostly-deprecated |
b8d4c8d0 GM |
580 | feature for specifying that the minibuffer should start out with |
581 | certain text, instead of empty as usual. | |
582 | ||
583 | If @var{initial} is a string, the minibuffer starts out containing the | |
584 | text of the string, with point at the end, when the user starts to | |
585 | edit the text. If the user simply types @key{RET} to exit the | |
586 | minibuffer, it will use the initial input string to determine the | |
587 | value to return. | |
588 | ||
589 | @strong{We discourage use of a non-@code{nil} value for | |
590 | @var{initial}}, because initial input is an intrusive interface. | |
591 | History lists and default values provide a much more convenient method | |
592 | to offer useful default inputs to the user. | |
593 | ||
594 | There is just one situation where you should specify a string for an | |
595 | @var{initial} argument. This is when you specify a cons cell for the | |
9d2754f5 | 596 | @var{history} argument. @xref{Minibuffer History}. |
b8d4c8d0 GM |
597 | |
598 | @var{initial} can also be a cons cell of the form @code{(@var{string} | |
599 | . @var{position})}. This means to insert @var{string} in the | |
600 | minibuffer but put point at @var{position} within the string's text. | |
601 | ||
602 | As a historical accident, @var{position} was implemented | |
603 | inconsistently in different functions. In @code{completing-read}, | |
604 | @var{position}'s value is interpreted as origin-zero; that is, a value | |
605 | of 0 means the beginning of the string, 1 means after the first | |
606 | character, etc. In @code{read-minibuffer}, and the other | |
607 | non-completion minibuffer input functions that support this argument, | |
c0ea08d2 | 608 | 1 means the beginning of the string, 2 means after the first character, |
b8d4c8d0 GM |
609 | etc. |
610 | ||
c0ea08d2 | 611 | Use of a cons cell as the value for @var{initial} arguments is deprecated. |
b8d4c8d0 GM |
612 | |
613 | @node Completion | |
614 | @section Completion | |
615 | @cindex completion | |
616 | ||
617 | @dfn{Completion} is a feature that fills in the rest of a name | |
618 | starting from an abbreviation for it. Completion works by comparing the | |
619 | user's input against a list of valid names and determining how much of | |
620 | the name is determined uniquely by what the user has typed. For | |
621 | example, when you type @kbd{C-x b} (@code{switch-to-buffer}) and then | |
b58b1df8 | 622 | @c "This is the sort of English up with which I will not put." |
b8d4c8d0 GM |
623 | type the first few letters of the name of the buffer to which you wish |
624 | to switch, and then type @key{TAB} (@code{minibuffer-complete}), Emacs | |
625 | extends the name as far as it can. | |
626 | ||
627 | Standard Emacs commands offer completion for names of symbols, files, | |
628 | buffers, and processes; with the functions in this section, you can | |
629 | implement completion for other kinds of names. | |
630 | ||
631 | The @code{try-completion} function is the basic primitive for | |
632 | completion: it returns the longest determined completion of a given | |
633 | initial string, with a given set of strings to match against. | |
634 | ||
635 | The function @code{completing-read} provides a higher-level interface | |
636 | for completion. A call to @code{completing-read} specifies how to | |
637 | determine the list of valid names. The function then activates the | |
638 | minibuffer with a local keymap that binds a few keys to commands useful | |
639 | for completion. Other functions provide convenient simple interfaces | |
640 | for reading certain kinds of names with completion. | |
641 | ||
642 | @menu | |
643 | * Basic Completion:: Low-level functions for completing strings. | |
b8d4c8d0 GM |
644 | * Minibuffer Completion:: Invoking the minibuffer with completion. |
645 | * Completion Commands:: Minibuffer commands that do completion. | |
646 | * High-Level Completion:: Convenient special cases of completion | |
b58b1df8 | 647 | (reading buffer names, variable names, etc.). |
e4372165 EZ |
648 | * Reading File Names:: Using completion to read file names and |
649 | shell commands. | |
321cc491 CY |
650 | * Completion Variables:: Variables controlling completion behavior. |
651 | * Programmed Completion:: Writing your own completion function. | |
60236b0d | 652 | * Completion in Buffers:: Completing text in ordinary buffers. |
b8d4c8d0 GM |
653 | @end menu |
654 | ||
655 | @node Basic Completion | |
656 | @subsection Basic Completion Functions | |
657 | ||
eb5ed549 CY |
658 | The following completion functions have nothing in themselves to do |
659 | with minibuffers. We describe them here to keep them near the | |
660 | higher-level completion features that do use the minibuffer. | |
b8d4c8d0 GM |
661 | |
662 | @defun try-completion string collection &optional predicate | |
663 | This function returns the longest common substring of all possible | |
60236b0d CY |
664 | completions of @var{string} in @var{collection}. |
665 | ||
666 | @cindex completion table | |
667 | The @var{collection} argument is called the @dfn{completion table}. | |
668 | Its value must be a list of strings, an alist whose keys are strings | |
669 | or symbols, an obarray, a hash table, or a completion function. | |
b8d4c8d0 GM |
670 | |
671 | Completion compares @var{string} against each of the permissible | |
eb5ed549 CY |
672 | completions specified by @var{collection}. If no permissible |
673 | completions match, @code{try-completion} returns @code{nil}. If there | |
674 | is just one matching completion, and the match is exact, it returns | |
675 | @code{t}. Otherwise, it returns the longest initial sequence common | |
676 | to all possible matching completions. | |
b8d4c8d0 GM |
677 | |
678 | If @var{collection} is an alist (@pxref{Association Lists}), the | |
679 | permissible completions are the elements of the alist that are either | |
fd5a8ae8 | 680 | strings, or conses whose @sc{car} is a string or symbol. |
b8d4c8d0 | 681 | Symbols are converted to strings using @code{symbol-name}. Other |
9d2754f5 | 682 | elements of the alist are ignored. (Remember that in Emacs Lisp, the |
b8d4c8d0 | 683 | elements of alists do not @emph{have} to be conses.) In particular, a |
fd5a8ae8 | 684 | list of strings is allowed, even though we usually do not |
b8d4c8d0 GM |
685 | think of such lists as alists. |
686 | ||
687 | @cindex obarray in completion | |
688 | If @var{collection} is an obarray (@pxref{Creating Symbols}), the names | |
b58b1df8 | 689 | of all symbols in the obarray form the set of permissible completions. |
b8d4c8d0 GM |
690 | |
691 | If @var{collection} is a hash table, then the keys that are strings | |
692 | are the possible completions. Other keys are ignored. | |
693 | ||
60236b0d CY |
694 | You can also use a function as @var{collection}. Then the function is |
695 | solely responsible for performing completion; @code{try-completion} | |
696 | returns whatever this function returns. The function is called with | |
697 | three arguments: @var{string}, @var{predicate} and @code{nil} (the | |
e68b393e | 698 | third argument is so that the same function can be used |
60236b0d CY |
699 | in @code{all-completions} and do the appropriate thing in either |
700 | case). @xref{Programmed Completion}. | |
b8d4c8d0 GM |
701 | |
702 | If the argument @var{predicate} is non-@code{nil}, then it must be a | |
703 | function of one argument, unless @var{collection} is a hash table, in | |
704 | which case it should be a function of two arguments. It is used to | |
705 | test each possible match, and the match is accepted only if | |
706 | @var{predicate} returns non-@code{nil}. The argument given to | |
707 | @var{predicate} is either a string or a cons cell (the @sc{car} of | |
708 | which is a string) from the alist, or a symbol (@emph{not} a symbol | |
709 | name) from the obarray. If @var{collection} is a hash table, | |
710 | @var{predicate} is called with two arguments, the string key and the | |
711 | associated value. | |
712 | ||
713 | In addition, to be acceptable, a completion must also match all the | |
714 | regular expressions in @code{completion-regexp-list}. (Unless | |
715 | @var{collection} is a function, in which case that function has to | |
716 | handle @code{completion-regexp-list} itself.) | |
717 | ||
718 | In the first of the following examples, the string @samp{foo} is | |
719 | matched by three of the alist @sc{car}s. All of the matches begin with | |
720 | the characters @samp{fooba}, so that is the result. In the second | |
e68b393e GM |
721 | example, there is only one possible match, and it is exact, so the |
722 | return value is @code{t}. | |
b8d4c8d0 GM |
723 | |
724 | @smallexample | |
725 | @group | |
726 | (try-completion | |
727 | "foo" | |
728 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))) | |
729 | @result{} "fooba" | |
730 | @end group | |
731 | ||
732 | @group | |
733 | (try-completion "foo" '(("barfoo" 2) ("foo" 3))) | |
734 | @result{} t | |
735 | @end group | |
736 | @end smallexample | |
737 | ||
738 | In the following example, numerous symbols begin with the characters | |
739 | @samp{forw}, and all of them begin with the word @samp{forward}. In | |
740 | most of the symbols, this is followed with a @samp{-}, but not in all, | |
741 | so no more than @samp{forward} can be completed. | |
742 | ||
743 | @smallexample | |
744 | @group | |
745 | (try-completion "forw" obarray) | |
746 | @result{} "forward" | |
747 | @end group | |
748 | @end smallexample | |
749 | ||
750 | Finally, in the following example, only two of the three possible | |
751 | matches pass the predicate @code{test} (the string @samp{foobaz} is | |
752 | too short). Both of those begin with the string @samp{foobar}. | |
753 | ||
754 | @smallexample | |
755 | @group | |
756 | (defun test (s) | |
757 | (> (length (car s)) 6)) | |
758 | @result{} test | |
759 | @end group | |
760 | @group | |
761 | (try-completion | |
762 | "foo" | |
763 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) | |
764 | 'test) | |
765 | @result{} "foobar" | |
766 | @end group | |
767 | @end smallexample | |
768 | @end defun | |
769 | ||
b58b1df8 GM |
770 | @c Removed obsolete argument nospace. |
771 | @defun all-completions string collection &optional predicate | |
b8d4c8d0 | 772 | This function returns a list of all possible completions of |
b58b1df8 GM |
773 | @var{string}. The arguments to this function |
774 | @c (aside from @var{nospace}) | |
775 | are the same as those of @code{try-completion}, and it | |
776 | uses @code{completion-regexp-list} in the same way that | |
16d1ff5f CY |
777 | @code{try-completion} does. |
778 | ||
b58b1df8 | 779 | @ignore |
16d1ff5f CY |
780 | The optional argument @var{nospace} is obsolete. If it is |
781 | non-@code{nil}, completions that start with a space are ignored unless | |
782 | @var{string} starts with a space. | |
b58b1df8 | 783 | @end ignore |
b8d4c8d0 GM |
784 | |
785 | If @var{collection} is a function, it is called with three arguments: | |
786 | @var{string}, @var{predicate} and @code{t}; then @code{all-completions} | |
787 | returns whatever the function returns. @xref{Programmed Completion}. | |
788 | ||
789 | Here is an example, using the function @code{test} shown in the | |
790 | example for @code{try-completion}: | |
791 | ||
792 | @smallexample | |
793 | @group | |
794 | (defun test (s) | |
795 | (> (length (car s)) 6)) | |
796 | @result{} test | |
797 | @end group | |
798 | ||
799 | @group | |
800 | (all-completions | |
801 | "foo" | |
802 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) | |
803 | 'test) | |
804 | @result{} ("foobar1" "foobar2") | |
805 | @end group | |
806 | @end smallexample | |
807 | @end defun | |
808 | ||
809 | @defun test-completion string collection &optional predicate | |
810 | @anchor{Definition of test-completion} | |
811 | This function returns non-@code{nil} if @var{string} is a valid | |
321cc491 | 812 | completion alternative specified by @var{collection} and |
b8d4c8d0 GM |
813 | @var{predicate}. The arguments are the same as in |
814 | @code{try-completion}. For instance, if @var{collection} is a list of | |
815 | strings, this is true if @var{string} appears in the list and | |
816 | @var{predicate} is satisfied. | |
817 | ||
818 | This function uses @code{completion-regexp-list} in the same | |
819 | way that @code{try-completion} does. | |
820 | ||
821 | If @var{predicate} is non-@code{nil} and if @var{collection} contains | |
822 | several strings that are equal to each other, as determined by | |
823 | @code{compare-strings} according to @code{completion-ignore-case}, | |
824 | then @var{predicate} should accept either all or none of them. | |
825 | Otherwise, the return value of @code{test-completion} is essentially | |
826 | unpredictable. | |
827 | ||
828 | If @var{collection} is a function, it is called with three arguments, | |
829 | the values @var{string}, @var{predicate} and @code{lambda}; whatever | |
830 | it returns, @code{test-completion} returns in turn. | |
7f4b4249 | 831 | @end defun |
637821cd SM |
832 | |
833 | @defun completion-boundaries string collection predicate suffix | |
834 | This function returns the boundaries of the field on which @var{collection} | |
835 | will operate, assuming that @var{string} holds the text before point | |
836 | and @var{suffix} holds the text after point. | |
837 | ||
838 | Normally completion operates on the whole string, so for all normal | |
839 | collections, this will always return @code{(0 . (length | |
840 | @var{suffix}))}. But more complex completion such as completion on | |
841 | files is done one field at a time. For example, completion of | |
842 | @code{"/usr/sh"} will include @code{"/usr/share/"} but not | |
843 | @code{"/usr/share/doc"} even if @code{"/usr/share/doc"} exists. | |
844 | Also @code{all-completions} on @code{"/usr/sh"} will not include | |
845 | @code{"/usr/share/"} but only @code{"share/"}. So if @var{string} is | |
846 | @code{"/usr/sh"} and @var{suffix} is @code{"e/doc"}, | |
847 | @code{completion-boundaries} will return @code{(5 . 1)} which tells us | |
848 | that the @var{collection} will only return completion information that | |
849 | pertains to the area after @code{"/usr/"} and before @code{"/doc"}. | |
b8d4c8d0 GM |
850 | @end defun |
851 | ||
eb5ed549 | 852 | If you store a completion alist in a variable, you should mark the |
b58b1df8 | 853 | variable as ``risky'' by giving it a non-@code{nil} |
eb5ed549 CY |
854 | @code{risky-local-variable} property. @xref{File Local Variables}. |
855 | ||
b8d4c8d0 | 856 | @defvar completion-ignore-case |
049bcbcb CY |
857 | If the value of this variable is non-@code{nil}, case is not |
858 | considered significant in completion. Within @code{read-file-name}, | |
859 | this variable is overridden by | |
860 | @code{read-file-name-completion-ignore-case} (@pxref{Reading File | |
861 | Names}); within @code{read-buffer}, it is overridden by | |
862 | @code{read-buffer-completion-ignore-case} (@pxref{High-Level | |
863 | Completion}). | |
b8d4c8d0 GM |
864 | @end defvar |
865 | ||
866 | @defvar completion-regexp-list | |
867 | This is a list of regular expressions. The completion functions only | |
868 | consider a completion acceptable if it matches all regular expressions | |
869 | in this list, with @code{case-fold-search} (@pxref{Searching and Case}) | |
870 | bound to the value of @code{completion-ignore-case}. | |
871 | @end defvar | |
872 | ||
873 | @defmac lazy-completion-table var fun | |
874 | This macro provides a way to initialize the variable @var{var} as a | |
875 | collection for completion in a lazy way, not computing its actual | |
876 | contents until they are first needed. You use this macro to produce a | |
877 | value that you store in @var{var}. The actual computation of the | |
878 | proper value is done the first time you do completion using @var{var}. | |
879 | It is done by calling @var{fun} with no arguments. The | |
880 | value @var{fun} returns becomes the permanent value of @var{var}. | |
881 | ||
b58b1df8 | 882 | Here is an example: |
b8d4c8d0 GM |
883 | |
884 | @smallexample | |
885 | (defvar foo (lazy-completion-table foo make-my-alist)) | |
886 | @end smallexample | |
887 | @end defmac | |
888 | ||
889 | @node Minibuffer Completion | |
890 | @subsection Completion and the Minibuffer | |
891 | @cindex minibuffer completion | |
892 | @cindex reading from minibuffer with completion | |
893 | ||
894 | This section describes the basic interface for reading from the | |
895 | minibuffer with completion. | |
896 | ||
9d2754f5 | 897 | @defun completing-read prompt collection &optional predicate require-match initial history default inherit-input-method |
b8d4c8d0 GM |
898 | This function reads a string in the minibuffer, assisting the user by |
899 | providing completion. It activates the minibuffer with prompt | |
900 | @var{prompt}, which must be a string. | |
901 | ||
60236b0d CY |
902 | The actual completion is done by passing the completion table |
903 | @var{collection} and the completion predicate @var{predicate} to the | |
904 | function @code{try-completion} (@pxref{Basic Completion}). This | |
905 | happens in certain commands bound in the local keymaps used for | |
906 | completion. Some of these commands also call @code{test-completion}. | |
907 | Thus, if @var{predicate} is non-@code{nil}, it should be compatible | |
908 | with @var{collection} and @code{completion-ignore-case}. | |
909 | @xref{Definition of test-completion}. | |
b8d4c8d0 | 910 | |
b613b1dc CY |
911 | The value of the optional argument @var{require-match} determines how |
912 | the user may exit the minibuffer: | |
913 | ||
914 | @itemize @bullet | |
915 | @item | |
916 | If @code{nil}, the usual minibuffer exit commands work regardless of | |
917 | the input in the minibuffer. | |
918 | ||
919 | @item | |
920 | If @code{t}, the usual minibuffer exit commands won't exit unless the | |
921 | input completes to an element of @var{collection}. | |
922 | ||
923 | @item | |
924 | If @code{confirm}, the user can exit with any input, but is asked for | |
925 | confirmation if the input is not an element of @var{collection}. | |
926 | ||
927 | @item | |
928 | If @code{confirm-after-completion}, the user can exit with any input, | |
929 | but is asked for confirmation if the preceding command was a | |
930 | completion command (i.e., one of the commands in | |
931 | @code{minibuffer-confirm-exit-commands}) and the resulting input is | |
932 | not an element of @var{collection}. @xref{Completion Commands}. | |
933 | ||
934 | @item | |
935 | Any other value of @var{require-match} behaves like @code{t}, except | |
936 | that the exit commands won't exit if it performs completion. | |
937 | @end itemize | |
b8d4c8d0 GM |
938 | |
939 | However, empty input is always permitted, regardless of the value of | |
c1d2409c RS |
940 | @var{require-match}; in that case, @code{completing-read} returns the |
941 | first element of @var{default}, if it is a list; @code{""}, if | |
70ee951b JL |
942 | @var{default} is @code{nil}; or @var{default}. The string or strings |
943 | in @var{default} are also available to the user through the history | |
c1d2409c | 944 | commands. |
b8d4c8d0 GM |
945 | |
946 | The function @code{completing-read} uses | |
947 | @code{minibuffer-local-completion-map} as the keymap if | |
948 | @var{require-match} is @code{nil}, and uses | |
949 | @code{minibuffer-local-must-match-map} if @var{require-match} is | |
950 | non-@code{nil}. @xref{Completion Commands}. | |
951 | ||
9d2754f5 | 952 | The argument @var{history} specifies which history list variable to use for |
b8d4c8d0 GM |
953 | saving the input and for minibuffer history commands. It defaults to |
954 | @code{minibuffer-history}. @xref{Minibuffer History}. | |
955 | ||
956 | The argument @var{initial} is mostly deprecated; we recommend using a | |
957 | non-@code{nil} value only in conjunction with specifying a cons cell | |
9d2754f5 | 958 | for @var{history}. @xref{Initial Input}. For default input, use |
b8d4c8d0 GM |
959 | @var{default} instead. |
960 | ||
961 | If the argument @var{inherit-input-method} is non-@code{nil}, then the | |
962 | minibuffer inherits the current input method (@pxref{Input | |
963 | Methods}) and the setting of @code{enable-multibyte-characters} | |
964 | (@pxref{Text Representations}) from whichever buffer was current before | |
965 | entering the minibuffer. | |
966 | ||
b58b1df8 | 967 | If the variable @code{completion-ignore-case} is |
b8d4c8d0 GM |
968 | non-@code{nil}, completion ignores case when comparing the input |
969 | against the possible matches. @xref{Basic Completion}. In this mode | |
970 | of operation, @var{predicate} must also ignore case, or you will get | |
971 | surprising results. | |
972 | ||
973 | Here's an example of using @code{completing-read}: | |
974 | ||
975 | @smallexample | |
976 | @group | |
977 | (completing-read | |
978 | "Complete a foo: " | |
979 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) | |
980 | nil t "fo") | |
981 | @end group | |
982 | ||
983 | @group | |
984 | ;; @r{After evaluation of the preceding expression,} | |
985 | ;; @r{the following appears in the minibuffer:} | |
986 | ||
987 | ---------- Buffer: Minibuffer ---------- | |
988 | Complete a foo: fo@point{} | |
989 | ---------- Buffer: Minibuffer ---------- | |
990 | @end group | |
991 | @end smallexample | |
992 | ||
993 | @noindent | |
994 | If the user then types @kbd{@key{DEL} @key{DEL} b @key{RET}}, | |
995 | @code{completing-read} returns @code{barfoo}. | |
996 | ||
997 | The @code{completing-read} function binds variables to pass | |
998 | information to the commands that actually do completion. | |
999 | They are described in the following section. | |
1000 | @end defun | |
1001 | ||
245d176b CY |
1002 | @defvar completing-read-function |
1003 | The value of this variable must be a function, which is called by | |
1004 | @code{completing-read} to actually do its work. It should accept the | |
1005 | same arguments as @code{completing-read}. This can be bound to a | |
1006 | different function to completely override the normal behavior of | |
1007 | @code{completing-read}. | |
1008 | @end defvar | |
1009 | ||
b8d4c8d0 GM |
1010 | @node Completion Commands |
1011 | @subsection Minibuffer Commands that Do Completion | |
1012 | ||
1013 | This section describes the keymaps, commands and user options used | |
b613b1dc | 1014 | in the minibuffer to do completion. |
b8d4c8d0 GM |
1015 | |
1016 | @defvar minibuffer-completion-table | |
60236b0d CY |
1017 | The value of this variable is the completion table used for completion |
1018 | in the minibuffer. This is the global variable that contains what | |
b8d4c8d0 | 1019 | @code{completing-read} passes to @code{try-completion}. It is used by |
60236b0d CY |
1020 | minibuffer completion commands such as |
1021 | @code{minibuffer-complete-word}. | |
b8d4c8d0 GM |
1022 | @end defvar |
1023 | ||
1024 | @defvar minibuffer-completion-predicate | |
1025 | This variable's value is the predicate that @code{completing-read} | |
1026 | passes to @code{try-completion}. The variable is also used by the other | |
1027 | minibuffer completion functions. | |
1028 | @end defvar | |
1029 | ||
1030 | @defvar minibuffer-completion-confirm | |
b613b1dc CY |
1031 | This variable determines whether Emacs asks for confirmation before |
1032 | exiting the minibuffer; @code{completing-read} binds this variable, | |
1033 | and the function @code{minibuffer-complete-and-exit} checks the value | |
1034 | before exiting. If the value is @code{nil}, confirmation is not | |
1035 | required. If the value is @code{confirm}, the user may exit with an | |
1036 | input that is not a valid completion alternative, but Emacs asks for | |
1037 | confirmation. If the value is @code{confirm-after-completion}, the | |
1038 | user may exit with an input that is not a valid completion | |
1039 | alternative, but Emacs asks for confirmation if the user submitted the | |
1040 | input right after any of the completion commands in | |
1041 | @code{minibuffer-confirm-exit-commands}. | |
1042 | @end defvar | |
1043 | ||
1044 | @defvar minibuffer-confirm-exit-commands | |
1045 | This variable holds a list of commands that cause Emacs to ask for | |
1046 | confirmation before exiting the minibuffer, if the @var{require-match} | |
1047 | argument to @code{completing-read} is @code{confirm-after-completion}. | |
1048 | The confirmation is requested if the user attempts to exit the | |
1049 | minibuffer immediately after calling any command in this list. | |
b8d4c8d0 GM |
1050 | @end defvar |
1051 | ||
1052 | @deffn Command minibuffer-complete-word | |
1053 | This function completes the minibuffer contents by at most a single | |
1054 | word. Even if the minibuffer contents have only one completion, | |
1055 | @code{minibuffer-complete-word} does not add any characters beyond the | |
1056 | first character that is not a word constituent. @xref{Syntax Tables}. | |
1057 | @end deffn | |
1058 | ||
1059 | @deffn Command minibuffer-complete | |
1060 | This function completes the minibuffer contents as far as possible. | |
1061 | @end deffn | |
1062 | ||
1063 | @deffn Command minibuffer-complete-and-exit | |
1064 | This function completes the minibuffer contents, and exits if | |
1065 | confirmation is not required, i.e., if | |
1066 | @code{minibuffer-completion-confirm} is @code{nil}. If confirmation | |
1067 | @emph{is} required, it is given by repeating this command | |
1068 | immediately---the command is programmed to work without confirmation | |
1069 | when run twice in succession. | |
1070 | @end deffn | |
1071 | ||
1072 | @deffn Command minibuffer-completion-help | |
1073 | This function creates a list of the possible completions of the | |
1074 | current minibuffer contents. It works by calling @code{all-completions} | |
1075 | using the value of the variable @code{minibuffer-completion-table} as | |
1076 | the @var{collection} argument, and the value of | |
1077 | @code{minibuffer-completion-predicate} as the @var{predicate} argument. | |
1078 | The list of completions is displayed as text in a buffer named | |
2bb0eca1 | 1079 | @file{*Completions*}. |
b8d4c8d0 GM |
1080 | @end deffn |
1081 | ||
1082 | @defun display-completion-list completions &optional common-substring | |
1083 | This function displays @var{completions} to the stream in | |
1084 | @code{standard-output}, usually a buffer. (@xref{Read and Print}, for more | |
1085 | information about streams.) The argument @var{completions} is normally | |
1086 | a list of completions just returned by @code{all-completions}, but it | |
1087 | does not have to be. Each element may be a symbol or a string, either | |
1088 | of which is simply printed. It can also be a list of two strings, | |
1089 | which is printed as if the strings were concatenated. The first of | |
1090 | the two strings is the actual completion, the second string serves as | |
1091 | annotation. | |
1092 | ||
1093 | The argument @var{common-substring} is the prefix that is common to | |
1094 | all the completions. With normal Emacs completion, it is usually the | |
1095 | same as the string that was completed. @code{display-completion-list} | |
1096 | uses this to highlight text in the completion list for better visual | |
1097 | feedback. This is not needed in the minibuffer; for minibuffer | |
1098 | completion, you can pass @code{nil}. | |
1099 | ||
b58b1df8 GM |
1100 | This function is called by @code{minibuffer-completion-help}. A |
1101 | common way to use it is together with | |
b8d4c8d0 GM |
1102 | @code{with-output-to-temp-buffer}, like this: |
1103 | ||
1104 | @example | |
1105 | (with-output-to-temp-buffer "*Completions*" | |
1106 | (display-completion-list | |
1107 | (all-completions (buffer-string) my-alist) | |
1108 | (buffer-string))) | |
1109 | @end example | |
1110 | @end defun | |
1111 | ||
1112 | @defopt completion-auto-help | |
1113 | If this variable is non-@code{nil}, the completion commands | |
1114 | automatically display a list of possible completions whenever nothing | |
1115 | can be completed because the next character is not uniquely determined. | |
1116 | @end defopt | |
1117 | ||
1118 | @defvar minibuffer-local-completion-map | |
1119 | @code{completing-read} uses this value as the local keymap when an | |
1120 | exact match of one of the completions is not required. By default, this | |
1121 | keymap makes the following bindings: | |
1122 | ||
1123 | @table @asis | |
1124 | @item @kbd{?} | |
1125 | @code{minibuffer-completion-help} | |
1126 | ||
1127 | @item @key{SPC} | |
1128 | @code{minibuffer-complete-word} | |
1129 | ||
1130 | @item @key{TAB} | |
1131 | @code{minibuffer-complete} | |
1132 | @end table | |
1133 | ||
1134 | @noindent | |
b58b1df8 | 1135 | and uses @code{minibuffer-local-map} as its parent keymap |
b8d4c8d0 GM |
1136 | (@pxref{Definition of minibuffer-local-map}). |
1137 | @end defvar | |
1138 | ||
1139 | @defvar minibuffer-local-must-match-map | |
1140 | @code{completing-read} uses this value as the local keymap when an | |
1141 | exact match of one of the completions is required. Therefore, no keys | |
1142 | are bound to @code{exit-minibuffer}, the command that exits the | |
1143 | minibuffer unconditionally. By default, this keymap makes the following | |
1144 | bindings: | |
1145 | ||
1146 | @table @asis | |
b8d4c8d0 GM |
1147 | @item @kbd{C-j} |
1148 | @code{minibuffer-complete-and-exit} | |
1149 | ||
1150 | @item @key{RET} | |
1151 | @code{minibuffer-complete-and-exit} | |
1152 | @end table | |
1153 | ||
1154 | @noindent | |
b58b1df8 | 1155 | and uses @code{minibuffer-local-completion-map} as its parent keymap. |
b8d4c8d0 GM |
1156 | @end defvar |
1157 | ||
1158 | @defvar minibuffer-local-filename-completion-map | |
b58b1df8 GM |
1159 | This is a sparse keymap that simply unbinds @key{SPC}; because |
1160 | filenames can contain spaces. The function @code{read-file-name} | |
1161 | combines this keymap with either @code{minibuffer-local-completion-map} | |
1162 | or @code{minibuffer-local-must-match-map}. | |
b8d4c8d0 GM |
1163 | @end defvar |
1164 | ||
b8d4c8d0 GM |
1165 | |
1166 | @node High-Level Completion | |
e4372165 | 1167 | @subsection High-Level Completion Functions |
b8d4c8d0 | 1168 | |
b58b1df8 | 1169 | This section describes the higher-level convenience functions for |
b8d4c8d0 GM |
1170 | reading certain sorts of names with completion. |
1171 | ||
1172 | In most cases, you should not call these functions in the middle of a | |
1173 | Lisp function. When possible, do all minibuffer input as part of | |
1174 | reading the arguments for a command, in the @code{interactive} | |
1175 | specification. @xref{Defining Commands}. | |
1176 | ||
b613b1dc | 1177 | @defun read-buffer prompt &optional default require-match |
b8d4c8d0 GM |
1178 | This function reads the name of a buffer and returns it as a string. |
1179 | The argument @var{default} is the default name to use, the value to | |
1180 | return if the user exits with an empty minibuffer. If non-@code{nil}, | |
c066bafa JL |
1181 | it should be a string, a list of strings, or a buffer. If it is |
1182 | a list, the default value is the first element of this list. It is | |
1183 | mentioned in the prompt, but is not inserted in the minibuffer as | |
1184 | initial input. | |
b8d4c8d0 GM |
1185 | |
1186 | The argument @var{prompt} should be a string ending with a colon and a | |
1187 | space. If @var{default} is non-@code{nil}, the function inserts it in | |
1188 | @var{prompt} before the colon to follow the convention for reading from | |
1189 | the minibuffer with a default value (@pxref{Programming Tips}). | |
1190 | ||
b613b1dc CY |
1191 | The optional argument @var{require-match} has the same meaning as in |
1192 | @code{completing-read}. @xref{Minibuffer Completion}. | |
b8d4c8d0 GM |
1193 | |
1194 | In the following example, the user enters @samp{minibuffer.t}, and | |
b613b1dc CY |
1195 | then types @key{RET}. The argument @var{require-match} is @code{t}, |
1196 | and the only buffer name starting with the given input is | |
b8d4c8d0 GM |
1197 | @samp{minibuffer.texi}, so that name is the value. |
1198 | ||
1199 | @example | |
1200 | (read-buffer "Buffer name: " "foo" t) | |
1201 | @group | |
1202 | ;; @r{After evaluation of the preceding expression,} | |
1203 | ;; @r{the following prompt appears,} | |
1204 | ;; @r{with an empty minibuffer:} | |
1205 | @end group | |
1206 | ||
1207 | @group | |
1208 | ---------- Buffer: Minibuffer ---------- | |
1209 | Buffer name (default foo): @point{} | |
1210 | ---------- Buffer: Minibuffer ---------- | |
1211 | @end group | |
1212 | ||
1213 | @group | |
1214 | ;; @r{The user types @kbd{minibuffer.t @key{RET}}.} | |
1215 | @result{} "minibuffer.texi" | |
1216 | @end group | |
1217 | @end example | |
1218 | @end defun | |
1219 | ||
01f17ae2 | 1220 | @defopt read-buffer-function |
b4f588fa JB |
1221 | This variable specifies how to read buffer names. The function is |
1222 | called with the arguments passed to @code{read-buffer}. For example, | |
1223 | if you set this variable to @code{iswitchb-read-buffer}, all Emacs | |
1224 | commands that call @code{read-buffer} to read a buffer name will | |
1225 | actually use the @code{iswitchb} package to read it. | |
01f17ae2 | 1226 | @end defopt |
b8d4c8d0 | 1227 | |
01f17ae2 | 1228 | @defopt read-buffer-completion-ignore-case |
b613b1dc CY |
1229 | If this variable is non-@code{nil}, @code{read-buffer} ignores case |
1230 | when performing completion. | |
01f17ae2 | 1231 | @end defopt |
b613b1dc | 1232 | |
b8d4c8d0 GM |
1233 | @defun read-command prompt &optional default |
1234 | This function reads the name of a command and returns it as a Lisp | |
1235 | symbol. The argument @var{prompt} is used as in | |
1236 | @code{read-from-minibuffer}. Recall that a command is anything for | |
1237 | which @code{commandp} returns @code{t}, and a command name is a symbol | |
1238 | for which @code{commandp} returns @code{t}. @xref{Interactive Call}. | |
1239 | ||
1240 | The argument @var{default} specifies what to return if the user enters | |
c066bafa JL |
1241 | null input. It can be a symbol, a string or a list of strings. If it |
1242 | is a string, @code{read-command} interns it before returning it. | |
b58b1df8 | 1243 | If it is a list, @code{read-command} interns the first element of this list. |
c066bafa JL |
1244 | If @var{default} is @code{nil}, that means no default has been |
1245 | specified; then if the user enters null input, the return value is | |
1246 | @code{(intern "")}, that is, a symbol whose name is an empty string. | |
b8d4c8d0 GM |
1247 | |
1248 | @example | |
1249 | (read-command "Command name? ") | |
1250 | ||
1251 | @group | |
1252 | ;; @r{After evaluation of the preceding expression,} | |
1253 | ;; @r{the following prompt appears with an empty minibuffer:} | |
1254 | @end group | |
1255 | ||
1256 | @group | |
1257 | ---------- Buffer: Minibuffer ---------- | |
1258 | Command name? | |
1259 | ---------- Buffer: Minibuffer ---------- | |
1260 | @end group | |
1261 | @end example | |
1262 | ||
1263 | @noindent | |
1264 | If the user types @kbd{forward-c @key{RET}}, then this function returns | |
1265 | @code{forward-char}. | |
1266 | ||
1267 | The @code{read-command} function is a simplified interface to | |
1268 | @code{completing-read}. It uses the variable @code{obarray} so as to | |
1269 | complete in the set of extant Lisp symbols, and it uses the | |
1270 | @code{commandp} predicate so as to accept only command names: | |
1271 | ||
1272 | @cindex @code{commandp} example | |
1273 | @example | |
1274 | @group | |
1275 | (read-command @var{prompt}) | |
1276 | @equiv{} | |
1277 | (intern (completing-read @var{prompt} obarray | |
1278 | 'commandp t nil)) | |
1279 | @end group | |
1280 | @end example | |
1281 | @end defun | |
1282 | ||
1283 | @defun read-variable prompt &optional default | |
1284 | @anchor{Definition of read-variable} | |
c07a4c0b CY |
1285 | This function reads the name of a customizable variable and returns it |
1286 | as a symbol. Its arguments have the same form as those of | |
1287 | @code{read-command}. It behaves just like @code{read-command}, except | |
1288 | that it uses the predicate @code{custom-variable-p} instead of | |
1289 | @code{commandp}. | |
b8d4c8d0 GM |
1290 | @end defun |
1291 | ||
ef164dbc EZ |
1292 | @deffn Command read-color &optional prompt convert allow-empty display |
1293 | This function reads a string that is a color specification, either the | |
1294 | color's name or an RGB hex value such as @code{#RRRGGGBBB}. It | |
94bc7984 | 1295 | prompts with @var{prompt} (default: @code{"Color (name or #RGB triplet):"}) |
ef164dbc EZ |
1296 | and provides completion for color names, but not for hex RGB values. |
1297 | In addition to names of standard colors, completion candidates include | |
1298 | the foreground and background colors at point. | |
1299 | ||
1300 | Valid RGB values are described in @ref{Color Names}. | |
1301 | ||
94bc7984 | 1302 | The function's return value is the string typed by the user in the |
ef164dbc | 1303 | minibuffer. However, when called interactively or if the optional |
94bc7984 GM |
1304 | argument @var{convert} is non-@code{nil}, it converts any input color |
1305 | name into the corresponding RGB value string and instead returns that. | |
1306 | This function requires a valid color specification to be input. | |
b58b1df8 | 1307 | Empty color names are allowed when @var{allow-empty} is |
ef164dbc EZ |
1308 | non-@code{nil} and the user enters null input. |
1309 | ||
62e8099c | 1310 | Interactively, or when @var{display} is non-@code{nil}, the return |
ef164dbc EZ |
1311 | value is also displayed in the echo area. |
1312 | @end deffn | |
1313 | ||
b8d4c8d0 GM |
1314 | See also the functions @code{read-coding-system} and |
1315 | @code{read-non-nil-coding-system}, in @ref{User-Chosen Coding Systems}, | |
1316 | and @code{read-input-method-name}, in @ref{Input Methods}. | |
1317 | ||
1318 | @node Reading File Names | |
1319 | @subsection Reading File Names | |
1320 | @cindex read file names | |
1321 | @cindex prompt for file name | |
1322 | ||
62e8099c CY |
1323 | The high-level completion functions @code{read-file-name}, |
1324 | @code{read-directory-name}, and @code{read-shell-command} are designed | |
b58b1df8 | 1325 | to read file names, directory names, and shell commands, respectively. |
62e8099c CY |
1326 | They provide special features, including automatic insertion of the |
1327 | default directory. | |
b8d4c8d0 | 1328 | |
b613b1dc | 1329 | @defun read-file-name prompt &optional directory default require-match initial predicate |
0f063651 CY |
1330 | This function reads a file name, prompting with @var{prompt} and |
1331 | providing completion. | |
1332 | ||
1333 | As an exception, this function reads a file name using a graphical | |
b58b1df8 GM |
1334 | file dialog instead of the minibuffer, if all of the following are |
1335 | true: | |
1336 | ||
1337 | @enumerate | |
1338 | @item | |
1339 | It is invoked via a mouse command. | |
1340 | ||
1341 | @item | |
1342 | The selected frame is on a graphical display supporting such dialogs. | |
1343 | ||
1344 | @item | |
1345 | The variable @code{use-dialog-box} is non-@code{nil}. | |
1346 | @xref{Dialog Boxes,, Dialog Boxes, emacs, The GNU Emacs Manual}. | |
1347 | ||
1348 | @item | |
1349 | The @var{directory} argument, described below, does not specify a | |
1350 | remote file. @xref{Remote Files,, Remote Files, emacs, The GNU Emacs Manual}. | |
1351 | @end enumerate | |
1352 | ||
1353 | @noindent | |
1354 | The exact behavior when using a graphical file dialog is | |
1355 | platform-dependent. Here, we simply document the behavior when using | |
1356 | the minibuffer. | |
b8d4c8d0 | 1357 | |
b4d52acc CY |
1358 | @code{read-file-name} does not automatically expand the returned file |
1359 | name. You must call @code{expand-file-name} yourself if an absolute | |
1360 | file name is required. | |
b8d4c8d0 | 1361 | |
b4d52acc | 1362 | The optional argument @var{require-match} has the same meaning as in |
245d176b | 1363 | @code{completing-read}. @xref{Minibuffer Completion}. |
b8d4c8d0 GM |
1364 | |
1365 | The argument @var{directory} specifies the directory to use for | |
b4d52acc | 1366 | completing relative file names. It should be an absolute directory |
b58b1df8 | 1367 | name. If the variable @code{insert-default-directory} is non-@code{nil}, |
b8d4c8d0 GM |
1368 | @var{directory} is also inserted in the minibuffer as initial input. |
1369 | It defaults to the current buffer's value of @code{default-directory}. | |
1370 | ||
b8d4c8d0 GM |
1371 | If you specify @var{initial}, that is an initial file name to insert |
1372 | in the buffer (after @var{directory}, if that is inserted). In this | |
1373 | case, point goes at the beginning of @var{initial}. The default for | |
1374 | @var{initial} is @code{nil}---don't insert any file name. To see what | |
b58b1df8 GM |
1375 | @var{initial} does, try the command @kbd{C-x C-v} in a buffer visiting |
1376 | a file. @strong{Please note:} we recommend using @var{default} rather | |
1377 | than @var{initial} in most cases. | |
b8d4c8d0 GM |
1378 | |
1379 | If @var{default} is non-@code{nil}, then the function returns | |
1380 | @var{default} if the user exits the minibuffer with the same non-empty | |
1381 | contents that @code{read-file-name} inserted initially. The initial | |
1382 | minibuffer contents are always non-empty if | |
1383 | @code{insert-default-directory} is non-@code{nil}, as it is by | |
1384 | default. @var{default} is not checked for validity, regardless of the | |
b613b1dc | 1385 | value of @var{require-match}. However, if @var{require-match} is |
b8d4c8d0 GM |
1386 | non-@code{nil}, the initial minibuffer contents should be a valid file |
1387 | (or directory) name. Otherwise @code{read-file-name} attempts | |
1388 | completion if the user exits without any editing, and does not return | |
1389 | @var{default}. @var{default} is also available through the history | |
1390 | commands. | |
1391 | ||
1392 | If @var{default} is @code{nil}, @code{read-file-name} tries to find a | |
1393 | substitute default to use in its place, which it treats in exactly the | |
1394 | same way as if it had been specified explicitly. If @var{default} is | |
1395 | @code{nil}, but @var{initial} is non-@code{nil}, then the default is | |
1396 | the absolute file name obtained from @var{directory} and | |
1397 | @var{initial}. If both @var{default} and @var{initial} are @code{nil} | |
1398 | and the buffer is visiting a file, @code{read-file-name} uses the | |
1399 | absolute file name of that file as default. If the buffer is not | |
1400 | visiting a file, then there is no default. In that case, if the user | |
1401 | types @key{RET} without any editing, @code{read-file-name} simply | |
1402 | returns the pre-inserted contents of the minibuffer. | |
1403 | ||
1404 | If the user types @key{RET} in an empty minibuffer, this function | |
b613b1dc CY |
1405 | returns an empty string, regardless of the value of |
1406 | @var{require-match}. This is, for instance, how the user can make the | |
1407 | current buffer visit no file using @code{M-x set-visited-file-name}. | |
b8d4c8d0 GM |
1408 | |
1409 | If @var{predicate} is non-@code{nil}, it specifies a function of one | |
1410 | argument that decides which file names are acceptable completion | |
321cc491 | 1411 | alternatives. A file name is an acceptable value if @var{predicate} |
b8d4c8d0 GM |
1412 | returns non-@code{nil} for it. |
1413 | ||
b4d52acc | 1414 | Here is an example of using @code{read-file-name}: |
b8d4c8d0 GM |
1415 | |
1416 | @example | |
1417 | @group | |
1418 | (read-file-name "The file is ") | |
1419 | ||
1420 | ;; @r{After evaluation of the preceding expression,} | |
1421 | ;; @r{the following appears in the minibuffer:} | |
1422 | @end group | |
1423 | ||
1424 | @group | |
1425 | ---------- Buffer: Minibuffer ---------- | |
1426 | The file is /gp/gnu/elisp/@point{} | |
1427 | ---------- Buffer: Minibuffer ---------- | |
1428 | @end group | |
1429 | @end example | |
1430 | ||
1431 | @noindent | |
1432 | Typing @kbd{manual @key{TAB}} results in the following: | |
1433 | ||
1434 | @example | |
1435 | @group | |
1436 | ---------- Buffer: Minibuffer ---------- | |
1437 | The file is /gp/gnu/elisp/manual.texi@point{} | |
1438 | ---------- Buffer: Minibuffer ---------- | |
1439 | @end group | |
1440 | @end example | |
1441 | ||
1442 | @c Wordy to avoid overfull hbox in smallbook mode. | |
1443 | @noindent | |
1444 | If the user types @key{RET}, @code{read-file-name} returns the file name | |
1445 | as the string @code{"/gp/gnu/elisp/manual.texi"}. | |
1446 | @end defun | |
1447 | ||
1448 | @defvar read-file-name-function | |
1449 | If non-@code{nil}, this should be a function that accepts the same | |
1450 | arguments as @code{read-file-name}. When @code{read-file-name} is | |
1451 | called, it calls this function with the supplied arguments instead of | |
1452 | doing its usual work. | |
1453 | @end defvar | |
1454 | ||
01f17ae2 | 1455 | @defopt read-file-name-completion-ignore-case |
b8d4c8d0 GM |
1456 | If this variable is non-@code{nil}, @code{read-file-name} ignores case |
1457 | when performing completion. | |
01f17ae2 | 1458 | @end defopt |
b8d4c8d0 | 1459 | |
b613b1dc | 1460 | @defun read-directory-name prompt &optional directory default require-match initial |
b8d4c8d0 | 1461 | This function is like @code{read-file-name} but allows only directory |
321cc491 | 1462 | names as completion alternatives. |
b8d4c8d0 GM |
1463 | |
1464 | If @var{default} is @code{nil} and @var{initial} is non-@code{nil}, | |
1465 | @code{read-directory-name} constructs a substitute default by | |
1466 | combining @var{directory} (or the current buffer's default directory | |
1467 | if @var{directory} is @code{nil}) and @var{initial}. If both | |
1468 | @var{default} and @var{initial} are @code{nil}, this function uses | |
1469 | @var{directory} as substitute default, or the current buffer's default | |
1470 | directory if @var{directory} is @code{nil}. | |
1471 | @end defun | |
1472 | ||
1473 | @defopt insert-default-directory | |
1474 | This variable is used by @code{read-file-name}, and thus, indirectly, | |
1475 | by most commands reading file names. (This includes all commands that | |
1476 | use the code letters @samp{f} or @samp{F} in their interactive form. | |
1477 | @xref{Interactive Codes,, Code Characters for interactive}.) Its | |
1478 | value controls whether @code{read-file-name} starts by placing the | |
1479 | name of the default directory in the minibuffer, plus the initial file | |
b58b1df8 | 1480 | name, if any. If the value of this variable is @code{nil}, then |
b8d4c8d0 GM |
1481 | @code{read-file-name} does not place any initial input in the |
1482 | minibuffer (unless you specify initial input with the @var{initial} | |
1483 | argument). In that case, the default directory is still used for | |
1484 | completion of relative file names, but is not displayed. | |
1485 | ||
1486 | If this variable is @code{nil} and the initial minibuffer contents are | |
1487 | empty, the user may have to explicitly fetch the next history element | |
1488 | to access a default value. If the variable is non-@code{nil}, the | |
1489 | initial minibuffer contents are always non-empty and the user can | |
1490 | always request a default value by immediately typing @key{RET} in an | |
1491 | unedited minibuffer. (See above.) | |
1492 | ||
1493 | For example: | |
1494 | ||
1495 | @example | |
1496 | @group | |
1497 | ;; @r{Here the minibuffer starts out with the default directory.} | |
1498 | (let ((insert-default-directory t)) | |
1499 | (read-file-name "The file is ")) | |
1500 | @end group | |
1501 | ||
1502 | @group | |
1503 | ---------- Buffer: Minibuffer ---------- | |
1504 | The file is ~lewis/manual/@point{} | |
1505 | ---------- Buffer: Minibuffer ---------- | |
1506 | @end group | |
1507 | ||
1508 | @group | |
1509 | ;; @r{Here the minibuffer is empty and only the prompt} | |
1510 | ;; @r{appears on its line.} | |
1511 | (let ((insert-default-directory nil)) | |
1512 | (read-file-name "The file is ")) | |
1513 | @end group | |
1514 | ||
1515 | @group | |
1516 | ---------- Buffer: Minibuffer ---------- | |
1517 | The file is @point{} | |
1518 | ---------- Buffer: Minibuffer ---------- | |
1519 | @end group | |
1520 | @end example | |
1521 | @end defopt | |
1522 | ||
9d2754f5 | 1523 | @defun read-shell-command prompt &optional initial history &rest args |
e4372165 EZ |
1524 | This function reads a shell command from the minibuffer, prompting |
1525 | with @var{prompt} and providing intelligent completion. It completes | |
1526 | the first word of the command using candidates that are appropriate | |
d8f0f8a5 EZ |
1527 | for command names, and the rest of the command words as file names. |
1528 | ||
1529 | This function uses @code{minibuffer-local-shell-command-map} as the | |
9d2754f5 | 1530 | keymap for minibuffer input. The @var{history} argument specifies the |
d8f0f8a5 | 1531 | history list to use; if is omitted or @code{nil}, it defaults to |
e4372165 | 1532 | @code{shell-command-history} (@pxref{Minibuffer History, |
9d2754f5 | 1533 | shell-command-history}). The optional argument @var{initial} |
d8f0f8a5 EZ |
1534 | specifies the initial content of the minibuffer (@pxref{Initial |
1535 | Input}). The rest of @var{args}, if present, are used as the | |
1536 | @var{default} and @var{inherit-input-method} arguments in | |
1537 | @code{read-from-minibuffer} (@pxref{Text from Minibuffer}). | |
e4372165 EZ |
1538 | @end defun |
1539 | ||
1540 | @defvar minibuffer-local-shell-command-map | |
1541 | This keymap is used by @code{read-shell-command} for completing | |
b58b1df8 GM |
1542 | command and file names that are part of a shell command. It uses |
1543 | @code{minibuffer-local-map} as its parent keymap, and binds @key{TAB} | |
1544 | to @code{completion-at-point}. | |
e4372165 EZ |
1545 | @end defvar |
1546 | ||
321cc491 CY |
1547 | @node Completion Variables |
1548 | @subsection Completion Variables | |
dc1ce9aa | 1549 | |
b58b1df8 | 1550 | Here are some variables that can be used to alter the default |
321cc491 | 1551 | completion behavior. |
dc1ce9aa | 1552 | |
321cc491 | 1553 | @cindex completion styles |
dc1ce9aa | 1554 | @defopt completion-styles |
ea0ff314 CY |
1555 | The value of this variable is a list of completion style (symbols) to |
1556 | use for performing completion. A @dfn{completion style} is a set of | |
b58b1df8 | 1557 | rules for generating completions. Each symbol occurring this list |
ea0ff314 | 1558 | must have a corresponding entry in @code{completion-styles-alist}. |
dc1ce9aa CY |
1559 | @end defopt |
1560 | ||
1561 | @defvar completion-styles-alist | |
1562 | This variable stores a list of available completion styles. Each | |
321cc491 CY |
1563 | element in the list has the form |
1564 | ||
1565 | @example | |
ea0ff314 | 1566 | (@var{style} @var{try-completion} @var{all-completions} @var{doc}) |
321cc491 CY |
1567 | @end example |
1568 | ||
1569 | @noindent | |
ea0ff314 CY |
1570 | Here, @var{style} is the name of the completion style (a symbol), |
1571 | which may be used in the @code{completion-styles} variable to refer to | |
1572 | this style; @var{try-completion} is the function that does the | |
1573 | completion; @var{all-completions} is the function that lists the | |
1574 | completions; and @var{doc} is a string describing the completion | |
1575 | style. | |
321cc491 CY |
1576 | |
1577 | The @var{try-completion} and @var{all-completions} functions should | |
1578 | each accept four arguments: @var{string}, @var{collection}, | |
1579 | @var{predicate}, and @var{point}. The @var{string}, @var{collection}, | |
1580 | and @var{predicate} arguments have the same meanings as in | |
1581 | @code{try-completion} (@pxref{Basic Completion}), and the @var{point} | |
1582 | argument is the position of point within @var{string}. Each function | |
1583 | should return a non-@code{nil} value if it performed its job, and | |
1584 | @code{nil} if it did not (e.g.@: if there is no way to complete | |
1585 | @var{string} according to the completion style). | |
1586 | ||
1587 | When the user calls a completion command like | |
dc1ce9aa CY |
1588 | @code{minibuffer-complete} (@pxref{Completion Commands}), Emacs looks |
1589 | for the first style listed in @code{completion-styles} and calls its | |
1590 | @var{try-completion} function. If this function returns @code{nil}, | |
321cc491 CY |
1591 | Emacs moves to the next listed completion style and calls its |
1592 | @var{try-completion} function, and so on until one of the | |
1593 | @var{try-completion} functions successfully performs completion and | |
1594 | returns a non-@code{nil} value. A similar procedure is used for | |
1595 | listing completions, via the @var{all-completions} functions. | |
1596 | ||
1597 | @xref{Completion Styles,,, emacs, The GNU Emacs Manual}, for a | |
1598 | description of the available completion styles. | |
dc1ce9aa CY |
1599 | @end defvar |
1600 | ||
ea0ff314 CY |
1601 | @defopt completion-category-overrides |
1602 | This variable specifies special completion styles and other completion | |
1603 | behaviors to use when completing certain types of text. Its value | |
b58b1df8 GM |
1604 | should be an alist with elements of the form @code{(@var{category} |
1605 | . @var{alist})}. @var{category} is a symbol describing what is being | |
1606 | completed; currently, the @code{buffer}, @code{file}, and | |
1607 | @code{unicode-name} categories are defined, but others can be defined | |
1608 | via specialized completion functions (@pxref{Programmed Completion}). | |
1609 | @var{alist} is an association list describing how completion should | |
1610 | behave for the corresponding category. The following alist keys are | |
1611 | supported: | |
ea0ff314 CY |
1612 | |
1613 | @table @code | |
1614 | @item styles | |
1615 | The value should be a list of completion styles (symbols). | |
1616 | ||
1617 | @item cycle | |
1618 | The value should be a value for @code{completion-cycle-threshold} | |
1619 | (@pxref{Completion Options,,, emacs, The GNU Emacs Manual}) for this | |
1620 | category. | |
1621 | @end table | |
1622 | ||
1623 | @noindent | |
1624 | Additional alist entries may be defined in the future. | |
1625 | @end defopt | |
1626 | ||
321cc491 CY |
1627 | @defvar completion-extra-properties |
1628 | This variable is used to specify extra properties of the current | |
1629 | completion command. It is intended to be let-bound by specialized | |
1630 | completion commands. Its value should be a list of property and value | |
1631 | pairs. The following properties are supported: | |
1632 | ||
1633 | @table @code | |
1634 | @item :annotation-function | |
1635 | The value should be a function to add annotations in the completions | |
1636 | buffer. This function must accept one argument, a completion, and | |
1637 | should either return @code{nil} or a string to be displayed next to | |
1638 | the completion. | |
1639 | ||
1640 | @item :exit-function | |
1641 | The value should be a function to run after performing completion. | |
1642 | The function should accept two arguments, @var{string} and | |
1643 | @var{status}, where @var{string} is the text to which the field was | |
b58b1df8 | 1644 | completed, and @var{status} indicates what kind of operation happened: |
321cc491 CY |
1645 | @code{finished} if text is now complete, @code{sole} if the text |
1646 | cannot be further completed but completion is not finished, or | |
1647 | @code{exact} if the text is a valid completion but may be further | |
1648 | completed. | |
1649 | @end table | |
1650 | @end defvar | |
dc1ce9aa | 1651 | |
b8d4c8d0 GM |
1652 | @node Programmed Completion |
1653 | @subsection Programmed Completion | |
1654 | @cindex programmed completion | |
1655 | ||
fd5a8ae8 SM |
1656 | Sometimes it is not possible or convenient to create an alist or |
1657 | an obarray containing all the intended possible completions ahead | |
1658 | of time. In such a case, you can supply your own function to compute | |
1659 | the completion of a given string. This is called @dfn{programmed | |
1660 | completion}. Emacs uses programmed completion when completing file | |
1661 | names (@pxref{File Name Completion}), among many other cases. | |
b8d4c8d0 | 1662 | |
637821cd SM |
1663 | To use this feature, pass a function as the @var{collection} |
1664 | argument to @code{completing-read}. The function | |
b8d4c8d0 | 1665 | @code{completing-read} arranges to pass your completion function along |
637821cd SM |
1666 | to @code{try-completion}, @code{all-completions}, and other basic |
1667 | completion functions, which will then let your function do all | |
1668 | the work. | |
b8d4c8d0 GM |
1669 | |
1670 | The completion function should accept three arguments: | |
1671 | ||
1672 | @itemize @bullet | |
1673 | @item | |
1674 | The string to be completed. | |
1675 | ||
1676 | @item | |
321cc491 CY |
1677 | A predicate function with which to filter possible matches, or |
1678 | @code{nil} if none. The function should call the predicate for each | |
1679 | possible match, and ignore the match if the predicate returns | |
1680 | @code{nil}. | |
b8d4c8d0 GM |
1681 | |
1682 | @item | |
321cc491 CY |
1683 | A flag specifying the type of completion operation to perform. This |
1684 | is one of the following four values: | |
b8d4c8d0 | 1685 | |
321cc491 CY |
1686 | @table @code |
1687 | @item nil | |
1688 | This specifies a @code{try-completion} operation. The function should | |
1689 | return @code{t} if the specified string is a unique and exact match; | |
1690 | if there is more than one match, it should return the common substring | |
1691 | of all matches (if the string is an exact match for one completion | |
1692 | alternative but also matches other longer alternatives, the return | |
1693 | value is the string); if there are no matches, it should return | |
1694 | @code{nil}. | |
1695 | ||
1696 | @item t | |
1697 | This specifies an @code{all-completions} operation. The function | |
b8d4c8d0 GM |
1698 | should return a list of all possible completions of the specified |
1699 | string. | |
1700 | ||
321cc491 CY |
1701 | @item lambda |
1702 | This specifies a @code{test-completion} operation. The function | |
1703 | should return @code{t} if the specified string is an exact match for | |
1704 | some completion alternative; @code{nil} otherwise. | |
637821cd | 1705 | |
321cc491 CY |
1706 | @item (boundaries . @var{suffix}) |
1707 | This specifies a @code{completion-boundaries} operation. The function | |
9d2754f5 GM |
1708 | should return @code{(boundaries @var{start} . @var{end})}, where |
1709 | @var{start} is the position of the beginning boundary in the specified | |
1710 | string, and @var{end} is the position of the end boundary in | |
1711 | @var{suffix}. | |
ea0ff314 CY |
1712 | |
1713 | @item metadata | |
1714 | This specifies a request for information about the state of the | |
1715 | current completion. The function should return an alist, as described | |
1716 | below. The alist may contain any number of elements. | |
321cc491 | 1717 | @end table |
ea0ff314 CY |
1718 | |
1719 | @noindent | |
1720 | If the flag has any other value, the completion function should return | |
1721 | @code{nil}. | |
b8d4c8d0 GM |
1722 | @end itemize |
1723 | ||
ea0ff314 CY |
1724 | The following is a list of metadata entries that a completion function |
1725 | may return in response to a @code{metadata} flag argument: | |
1726 | ||
1727 | @table @code | |
1728 | @item category | |
1729 | The value should be a symbol describing what kind of text the | |
1730 | completion function is trying to complete. If the symbol matches one | |
1731 | of the keys in @code{completion-category-overrides}, the usual | |
1732 | completion behavior is overridden. @xref{Completion Variables}. | |
1733 | ||
1734 | @item annotation-function | |
1735 | The value should be a function for @dfn{annotating} completions. The | |
1736 | function should take one argument, @var{string}, which is a possible | |
1737 | completion. It should return a string, which is displayed after the | |
2bb0eca1 | 1738 | completion @var{string} in the @file{*Completions*} buffer. |
ea0ff314 CY |
1739 | |
1740 | @item display-sort-function | |
1741 | The value should be a function for sorting completions. The function | |
1742 | should take one argument, a list of completion strings, and return a | |
1743 | sorted list of completion strings. It is allowed to alter the input | |
1744 | list destructively. | |
1745 | ||
1746 | @item cycle-sort-function | |
1747 | The value should be a function for sorting completions, when | |
1748 | @code{completion-cycle-threshold} is non-@code{nil} and the user is | |
1749 | cycling through completion alternatives. @xref{Completion Options,,, | |
1750 | emacs, The GNU Emacs Manual}. Its argument list and return value are | |
1751 | the same as for @code{display-sort-function}. | |
1752 | @end table | |
1753 | ||
25c0d999 SM |
1754 | @defun completion-table-dynamic function |
1755 | This function is a convenient way to write a function that can act as | |
b58b1df8 | 1756 | a programmed completion function. The argument @var{function} should be |
b8d4c8d0 GM |
1757 | a function that takes one argument, a string, and returns an alist of |
1758 | possible completions of it. You can think of | |
25c0d999 | 1759 | @code{completion-table-dynamic} as a transducer between that interface |
b8d4c8d0 | 1760 | and the interface for programmed completion functions. |
25c0d999 | 1761 | @end defun |
b8d4c8d0 | 1762 | |
60236b0d CY |
1763 | @node Completion in Buffers |
1764 | @subsection Completion in Ordinary Buffers | |
1765 | @cindex inline completion | |
1766 | ||
1767 | @findex completion-at-point | |
1768 | Although completion is usually done in the minibuffer, the | |
1769 | completion facility can also be used on the text in ordinary Emacs | |
1770 | buffers. In many major modes, in-buffer completion is performed by | |
1771 | the @kbd{C-M-i} or @kbd{M-@key{TAB}} command, bound to | |
1772 | @code{completion-at-point}. @xref{Symbol Completion,,, emacs, The GNU | |
1773 | Emacs Manual}. This command uses the abnormal hook variable | |
1774 | @code{completion-at-point-functions}: | |
1775 | ||
1776 | @defvar completion-at-point-functions | |
1777 | The value of this abnormal hook should be a list of functions, which | |
1778 | are used to compute a completion table for completing the text at | |
1779 | point. It can be used by major modes to provide mode-specific | |
1780 | completion tables (@pxref{Major Mode Conventions}). | |
1781 | ||
1782 | When the command @code{completion-at-point} runs, it calls the | |
1783 | functions in the list one by one, without any argument. Each function | |
1784 | should return @code{nil} if it is unable to produce a completion table | |
1785 | for the text at point. Otherwise it should return a list of the form | |
1786 | ||
1787 | @example | |
1788 | (@var{start} @var{end} @var{collection} . @var{props}) | |
1789 | @end example | |
1790 | ||
1791 | @noindent | |
1792 | @var{start} and @var{end} delimit the text to complete (which should | |
1793 | enclose point). @var{collection} is a completion table for completing | |
1794 | that text, in a form suitable for passing as the second argument to | |
1795 | @code{try-completion} (@pxref{Basic Completion}); completion | |
1796 | alternatives will be generated from this completion table in the usual | |
1797 | way, via the completion styles defined in @code{completion-styles} | |
321cc491 | 1798 | (@pxref{Completion Variables}). @var{props} is a property list for |
245d176b CY |
1799 | additional information; any of the properties in |
1800 | @code{completion-extra-properties} are recognized (@pxref{Completion | |
1801 | Variables}), as well as the following additional ones: | |
60236b0d CY |
1802 | |
1803 | @table @code | |
1804 | @item :predicate | |
1805 | The value should be a predicate that completion candidates need to | |
1806 | satisfy. | |
1807 | ||
1808 | @item :exclusive | |
1809 | If the value is @code{no}, then if the completion table fails to match | |
b58b1df8 | 1810 | the text at point, @code{completion-at-point} moves on to the |
60236b0d CY |
1811 | next function in @code{completion-at-point-functions} instead of |
1812 | reporting a completion failure. | |
1813 | @end table | |
1814 | ||
1815 | A function in @code{completion-at-point-functions} may also return a | |
1816 | function. In that case, that returned function is called, with no | |
1817 | argument, and it is entirely responsible for performing the | |
1818 | completion. We discourage this usage; it is intended to help convert | |
1819 | old code to using @code{completion-at-point}. | |
1820 | ||
1821 | The first function in @code{completion-at-point-functions} to return a | |
1822 | non-@code{nil} value is used by @code{completion-at-point}. The | |
1823 | remaining functions are not called. The exception to this is when | |
b58b1df8 | 1824 | there is an @code{:exclusive} specification, as described above. |
60236b0d CY |
1825 | @end defvar |
1826 | ||
1827 | The following function provides a convenient way to perform | |
1828 | completion on an arbitrary stretch of text in an Emacs buffer: | |
1829 | ||
1830 | @defun completion-in-region start end collection &optional predicate | |
1831 | This function completes the text in the current buffer between the | |
1832 | positions @var{start} and @var{end}, using @var{collection}. The | |
1833 | argument @var{collection} has the same meaning as in | |
1834 | @code{try-completion} (@pxref{Basic Completion}). | |
1835 | ||
1836 | This function inserts the completion text directly into the current | |
1837 | buffer. Unlike @code{completing-read} (@pxref{Minibuffer | |
1838 | Completion}), it does not activate the minibuffer. | |
1839 | ||
1840 | For this function to work, point must be somewhere between @var{start} | |
1841 | and @var{end}. | |
1842 | @end defun | |
1843 | ||
1844 | ||
b8d4c8d0 GM |
1845 | @node Yes-or-No Queries |
1846 | @section Yes-or-No Queries | |
1847 | @cindex asking the user questions | |
1848 | @cindex querying the user | |
1849 | @cindex yes-or-no questions | |
1850 | ||
1851 | This section describes functions used to ask the user a yes-or-no | |
1852 | question. The function @code{y-or-n-p} can be answered with a single | |
1853 | character; it is useful for questions where an inadvertent wrong answer | |
1854 | will not have serious consequences. @code{yes-or-no-p} is suitable for | |
1855 | more momentous questions, since it requires three or four characters to | |
1856 | answer. | |
1857 | ||
1858 | If either of these functions is called in a command that was invoked | |
1859 | using the mouse---more precisely, if @code{last-nonmenu-event} | |
1860 | (@pxref{Command Loop Info}) is either @code{nil} or a list---then it | |
1861 | uses a dialog box or pop-up menu to ask the question. Otherwise, it | |
c0ea08d2 | 1862 | uses keyboard input. You can force use either of the mouse or of keyboard |
b8d4c8d0 GM |
1863 | input by binding @code{last-nonmenu-event} to a suitable value around |
1864 | the call. | |
1865 | ||
1866 | Strictly speaking, @code{yes-or-no-p} uses the minibuffer and | |
1867 | @code{y-or-n-p} does not; but it seems best to describe them together. | |
1868 | ||
1869 | @defun y-or-n-p prompt | |
1870 | This function asks the user a question, expecting input in the echo | |
1871 | area. It returns @code{t} if the user types @kbd{y}, @code{nil} if the | |
1872 | user types @kbd{n}. This function also accepts @key{SPC} to mean yes | |
9d2754f5 | 1873 | and @key{DEL} to mean no. It accepts @kbd{C-]} to mean ``quit'', like |
b8d4c8d0 GM |
1874 | @kbd{C-g}, because the question might look like a minibuffer and for |
1875 | that reason the user might try to use @kbd{C-]} to get out. The answer | |
1876 | is a single character, with no @key{RET} needed to terminate it. Upper | |
1877 | and lower case are equivalent. | |
1878 | ||
1879 | ``Asking the question'' means printing @var{prompt} in the echo area, | |
1880 | followed by the string @w{@samp{(y or n) }}. If the input is not one of | |
1881 | the expected answers (@kbd{y}, @kbd{n}, @kbd{@key{SPC}}, | |
1882 | @kbd{@key{DEL}}, or something that quits), the function responds | |
1883 | @samp{Please answer y or n.}, and repeats the request. | |
1884 | ||
1885 | This function does not actually use the minibuffer, since it does not | |
1886 | allow editing of the answer. It actually uses the echo area (@pxref{The | |
1887 | Echo Area}), which uses the same screen space as the minibuffer. The | |
1888 | cursor moves to the echo area while the question is being asked. | |
1889 | ||
1890 | The answers and their meanings, even @samp{y} and @samp{n}, are not | |
1891 | hardwired. The keymap @code{query-replace-map} specifies them. | |
1892 | @xref{Search and Replace}. | |
1893 | ||
1894 | In the following example, the user first types @kbd{q}, which is | |
1895 | invalid. At the next prompt the user types @kbd{y}. | |
1896 | ||
c0ea08d2 GM |
1897 | @c Need an interactive example, because otherwise the return value |
1898 | @c obscures the display of the valid answer. | |
b8d4c8d0 GM |
1899 | @smallexample |
1900 | @group | |
c0ea08d2 GM |
1901 | (defun ask () |
1902 | (interactive) | |
1903 | (y-or-n-p "Do you need a lift? ")) | |
b8d4c8d0 | 1904 | |
c0ea08d2 GM |
1905 | ;; @r{After evaluation of the preceding definition, @kbd{M-x ask}} |
1906 | ;; @r{causes the following prompt to appear in the echo area:} | |
b8d4c8d0 GM |
1907 | @end group |
1908 | ||
1909 | @group | |
1910 | ---------- Echo area ---------- | |
1911 | Do you need a lift? (y or n) | |
1912 | ---------- Echo area ---------- | |
1913 | @end group | |
1914 | ||
1915 | ;; @r{If the user then types @kbd{q}, the following appears:} | |
1916 | ||
1917 | @group | |
1918 | ---------- Echo area ---------- | |
1919 | Please answer y or n. Do you need a lift? (y or n) | |
1920 | ---------- Echo area ---------- | |
1921 | @end group | |
1922 | ||
1923 | ;; @r{When the user types a valid answer,} | |
1924 | ;; @r{it is displayed after the question:} | |
1925 | ||
1926 | @group | |
1927 | ---------- Echo area ---------- | |
1928 | Do you need a lift? (y or n) y | |
1929 | ---------- Echo area ---------- | |
1930 | @end group | |
1931 | @end smallexample | |
1932 | ||
1933 | @noindent | |
1934 | We show successive lines of echo area messages, but only one actually | |
1935 | appears on the screen at a time. | |
1936 | @end defun | |
1937 | ||
9d2754f5 | 1938 | @defun y-or-n-p-with-timeout prompt seconds default |
b8d4c8d0 GM |
1939 | Like @code{y-or-n-p}, except that if the user fails to answer within |
1940 | @var{seconds} seconds, this function stops waiting and returns | |
9d2754f5 | 1941 | @var{default}. It works by setting up a timer; see @ref{Timers}. |
b8d4c8d0 GM |
1942 | The argument @var{seconds} may be an integer or a floating point number. |
1943 | @end defun | |
1944 | ||
1945 | @defun yes-or-no-p prompt | |
1946 | This function asks the user a question, expecting input in the | |
1947 | minibuffer. It returns @code{t} if the user enters @samp{yes}, | |
1948 | @code{nil} if the user types @samp{no}. The user must type @key{RET} to | |
1949 | finalize the response. Upper and lower case are equivalent. | |
1950 | ||
1951 | @code{yes-or-no-p} starts by displaying @var{prompt} in the echo area, | |
1952 | followed by @w{@samp{(yes or no) }}. The user must type one of the | |
1953 | expected responses; otherwise, the function responds @samp{Please answer | |
1954 | yes or no.}, waits about two seconds and repeats the request. | |
1955 | ||
1956 | @code{yes-or-no-p} requires more work from the user than | |
1957 | @code{y-or-n-p} and is appropriate for more crucial decisions. | |
1958 | ||
1959 | Here is an example: | |
1960 | ||
1961 | @smallexample | |
1962 | @group | |
1963 | (yes-or-no-p "Do you really want to remove everything? ") | |
1964 | ||
1965 | ;; @r{After evaluation of the preceding expression,} | |
1966 | ;; @r{the following prompt appears,} | |
1967 | ;; @r{with an empty minibuffer:} | |
1968 | @end group | |
1969 | ||
1970 | @group | |
1971 | ---------- Buffer: minibuffer ---------- | |
1972 | Do you really want to remove everything? (yes or no) | |
1973 | ---------- Buffer: minibuffer ---------- | |
1974 | @end group | |
1975 | @end smallexample | |
1976 | ||
1977 | @noindent | |
1978 | If the user first types @kbd{y @key{RET}}, which is invalid because this | |
1979 | function demands the entire word @samp{yes}, it responds by displaying | |
1980 | these prompts, with a brief pause between them: | |
1981 | ||
1982 | @smallexample | |
1983 | @group | |
1984 | ---------- Buffer: minibuffer ---------- | |
1985 | Please answer yes or no. | |
1986 | Do you really want to remove everything? (yes or no) | |
1987 | ---------- Buffer: minibuffer ---------- | |
1988 | @end group | |
1989 | @end smallexample | |
1990 | @end defun | |
1991 | ||
1992 | @node Multiple Queries | |
1993 | @section Asking Multiple Y-or-N Questions | |
1994 | ||
1995 | When you have a series of similar questions to ask, such as ``Do you | |
1996 | want to save this buffer'' for each buffer in turn, you should use | |
1997 | @code{map-y-or-n-p} to ask the collection of questions, rather than | |
1998 | asking each question individually. This gives the user certain | |
1999 | convenient facilities such as the ability to answer the whole series at | |
2000 | once. | |
2001 | ||
2002 | @defun map-y-or-n-p prompter actor list &optional help action-alist no-cursor-in-echo-area | |
2003 | This function asks the user a series of questions, reading a | |
2004 | single-character answer in the echo area for each one. | |
2005 | ||
2006 | The value of @var{list} specifies the objects to ask questions about. | |
2007 | It should be either a list of objects or a generator function. If it is | |
2008 | a function, it should expect no arguments, and should return either the | |
c0ea08d2 | 2009 | next object to ask about, or @code{nil}, meaning to stop asking questions. |
b8d4c8d0 GM |
2010 | |
2011 | The argument @var{prompter} specifies how to ask each question. If | |
2012 | @var{prompter} is a string, the question text is computed like this: | |
2013 | ||
2014 | @example | |
2015 | (format @var{prompter} @var{object}) | |
2016 | @end example | |
2017 | ||
2018 | @noindent | |
2019 | where @var{object} is the next object to ask about (as obtained from | |
2020 | @var{list}). | |
2021 | ||
2022 | If not a string, @var{prompter} should be a function of one argument | |
2023 | (the next object to ask about) and should return the question text. If | |
2024 | the value is a string, that is the question to ask the user. The | |
c0ea08d2 GM |
2025 | function can also return @code{t}, meaning do act on this object (and |
2026 | don't ask the user), or @code{nil}, meaning ignore this object (and don't | |
b8d4c8d0 GM |
2027 | ask the user). |
2028 | ||
2029 | The argument @var{actor} says how to act on the answers that the user | |
2030 | gives. It should be a function of one argument, and it is called with | |
2031 | each object that the user says yes for. Its argument is always an | |
2032 | object obtained from @var{list}. | |
2033 | ||
2034 | If the argument @var{help} is given, it should be a list of this form: | |
2035 | ||
2036 | @example | |
2037 | (@var{singular} @var{plural} @var{action}) | |
2038 | @end example | |
2039 | ||
2040 | @noindent | |
2041 | where @var{singular} is a string containing a singular noun that | |
2042 | describes the objects conceptually being acted on, @var{plural} is the | |
2043 | corresponding plural noun, and @var{action} is a transitive verb | |
2044 | describing what @var{actor} does. | |
2045 | ||
2046 | If you don't specify @var{help}, the default is @code{("object" | |
2047 | "objects" "act on")}. | |
2048 | ||
2049 | Each time a question is asked, the user may enter @kbd{y}, @kbd{Y}, or | |
2050 | @key{SPC} to act on that object; @kbd{n}, @kbd{N}, or @key{DEL} to skip | |
2051 | that object; @kbd{!} to act on all following objects; @key{ESC} or | |
2052 | @kbd{q} to exit (skip all following objects); @kbd{.} (period) to act on | |
2053 | the current object and then exit; or @kbd{C-h} to get help. These are | |
2054 | the same answers that @code{query-replace} accepts. The keymap | |
2055 | @code{query-replace-map} defines their meaning for @code{map-y-or-n-p} | |
2056 | as well as for @code{query-replace}; see @ref{Search and Replace}. | |
2057 | ||
2058 | You can use @var{action-alist} to specify additional possible answers | |
2059 | and what they mean. It is an alist of elements of the form | |
2060 | @code{(@var{char} @var{function} @var{help})}, each of which defines one | |
2061 | additional answer. In this element, @var{char} is a character (the | |
2062 | answer); @var{function} is a function of one argument (an object from | |
2063 | @var{list}); @var{help} is a string. | |
2064 | ||
2065 | When the user responds with @var{char}, @code{map-y-or-n-p} calls | |
2066 | @var{function}. If it returns non-@code{nil}, the object is considered | |
9d2754f5 | 2067 | ``acted upon'', and @code{map-y-or-n-p} advances to the next object in |
b8d4c8d0 GM |
2068 | @var{list}. If it returns @code{nil}, the prompt is repeated for the |
2069 | same object. | |
2070 | ||
2071 | Normally, @code{map-y-or-n-p} binds @code{cursor-in-echo-area} while | |
2072 | prompting. But if @var{no-cursor-in-echo-area} is non-@code{nil}, it | |
2073 | does not do that. | |
2074 | ||
2075 | If @code{map-y-or-n-p} is called in a command that was invoked using the | |
2076 | mouse---more precisely, if @code{last-nonmenu-event} (@pxref{Command | |
2077 | Loop Info}) is either @code{nil} or a list---then it uses a dialog box | |
2078 | or pop-up menu to ask the question. In this case, it does not use | |
c0ea08d2 | 2079 | keyboard input or the echo area. You can force use either of the mouse or |
b8d4c8d0 GM |
2080 | of keyboard input by binding @code{last-nonmenu-event} to a suitable |
2081 | value around the call. | |
2082 | ||
2083 | The return value of @code{map-y-or-n-p} is the number of objects acted on. | |
2084 | @end defun | |
c0ea08d2 GM |
2085 | @c FIXME An example of this would be more useful than all the |
2086 | @c preceding examples of simple things. | |
b8d4c8d0 GM |
2087 | |
2088 | @node Reading a Password | |
2089 | @section Reading a Password | |
2090 | @cindex passwords, reading | |
2091 | ||
2092 | To read a password to pass to another program, you can use the | |
2093 | function @code{read-passwd}. | |
2094 | ||
2095 | @defun read-passwd prompt &optional confirm default | |
2096 | This function reads a password, prompting with @var{prompt}. It does | |
2097 | not echo the password as the user types it; instead, it echoes @samp{.} | |
2098 | for each character in the password. | |
2099 | ||
2100 | The optional argument @var{confirm}, if non-@code{nil}, says to read the | |
2101 | password twice and insist it must be the same both times. If it isn't | |
2102 | the same, the user has to type it over and over until the last two | |
2103 | times match. | |
2104 | ||
2105 | The optional argument @var{default} specifies the default password to | |
2106 | return if the user enters empty input. If @var{default} is @code{nil}, | |
2107 | then @code{read-passwd} returns the null string in that case. | |
2108 | @end defun | |
2109 | ||
2110 | @node Minibuffer Commands | |
2111 | @section Minibuffer Commands | |
2112 | ||
2113 | This section describes some commands meant for use in the | |
2114 | minibuffer. | |
2115 | ||
2116 | @deffn Command exit-minibuffer | |
2117 | This command exits the active minibuffer. It is normally bound to | |
2118 | keys in minibuffer local keymaps. | |
2119 | @end deffn | |
2120 | ||
2121 | @deffn Command self-insert-and-exit | |
2122 | This command exits the active minibuffer after inserting the last | |
21e96f8f | 2123 | character typed on the keyboard (found in @code{last-command-event}; |
b8d4c8d0 GM |
2124 | @pxref{Command Loop Info}). |
2125 | @end deffn | |
2126 | ||
2127 | @deffn Command previous-history-element n | |
2128 | This command replaces the minibuffer contents with the value of the | |
2129 | @var{n}th previous (older) history element. | |
2130 | @end deffn | |
2131 | ||
2132 | @deffn Command next-history-element n | |
2133 | This command replaces the minibuffer contents with the value of the | |
2134 | @var{n}th more recent history element. | |
2135 | @end deffn | |
2136 | ||
2137 | @deffn Command previous-matching-history-element pattern n | |
2138 | This command replaces the minibuffer contents with the value of the | |
2139 | @var{n}th previous (older) history element that matches @var{pattern} (a | |
2140 | regular expression). | |
2141 | @end deffn | |
2142 | ||
2143 | @deffn Command next-matching-history-element pattern n | |
2144 | This command replaces the minibuffer contents with the value of the | |
2145 | @var{n}th next (newer) history element that matches @var{pattern} (a | |
2146 | regular expression). | |
2147 | @end deffn | |
2148 | ||
c0ea08d2 GM |
2149 | @deffn Command previous-complete-history-element n |
2150 | This command replaces the minibuffer contents with the value of the | |
2151 | @var{n}th previous (older) history element that completes the current | |
2152 | contents of the minibuffer before the point. | |
2153 | @end deffn | |
2154 | ||
2155 | @deffn Command next-complete-history-element n | |
2156 | This command replaces the minibuffer contents with the value of the | |
2157 | @var{n}th next (newer) history element that completes the current | |
2158 | contents of the minibuffer before the point. | |
2159 | @end deffn | |
2160 | ||
2161 | ||
b8d4c8d0 GM |
2162 | @node Minibuffer Windows |
2163 | @section Minibuffer Windows | |
2164 | @cindex minibuffer windows | |
2165 | ||
2166 | These functions access and select minibuffer windows | |
2167 | and test whether they are active. | |
2168 | ||
2169 | @defun active-minibuffer-window | |
2170 | This function returns the currently active minibuffer window, or | |
c0ea08d2 | 2171 | @code{nil} if there is none. |
b8d4c8d0 GM |
2172 | @end defun |
2173 | ||
2174 | @defun minibuffer-window &optional frame | |
2175 | @anchor{Definition of minibuffer-window} | |
2176 | This function returns the minibuffer window used for frame @var{frame}. | |
2177 | If @var{frame} is @code{nil}, that stands for the current frame. Note | |
2178 | that the minibuffer window used by a frame need not be part of that | |
2179 | frame---a frame that has no minibuffer of its own necessarily uses some | |
2180 | other frame's minibuffer window. | |
2181 | @end defun | |
2182 | ||
2183 | @defun set-minibuffer-window window | |
2184 | This function specifies @var{window} as the minibuffer window to use. | |
2185 | This affects where the minibuffer is displayed if you put text in it | |
2186 | without invoking the usual minibuffer commands. It has no effect on | |
2187 | the usual minibuffer input functions because they all start by | |
2188 | choosing the minibuffer window according to the current frame. | |
2189 | @end defun | |
2190 | ||
2191 | @c Emacs 19 feature | |
2192 | @defun window-minibuffer-p &optional window | |
2193 | This function returns non-@code{nil} if @var{window} is a minibuffer | |
2194 | window. | |
2195 | @var{window} defaults to the selected window. | |
2196 | @end defun | |
2197 | ||
2198 | It is not correct to determine whether a given window is a minibuffer by | |
2199 | comparing it with the result of @code{(minibuffer-window)}, because | |
2200 | there can be more than one minibuffer window if there is more than one | |
2201 | frame. | |
2202 | ||
2203 | @defun minibuffer-window-active-p window | |
c0ea08d2 GM |
2204 | This function returns non-@code{nil} if @var{window} is the currently |
2205 | active minibuffer window. | |
b8d4c8d0 GM |
2206 | @end defun |
2207 | ||
2208 | @node Minibuffer Contents | |
2209 | @section Minibuffer Contents | |
2210 | ||
2211 | These functions access the minibuffer prompt and contents. | |
2212 | ||
2213 | @defun minibuffer-prompt | |
2214 | This function returns the prompt string of the currently active | |
2215 | minibuffer. If no minibuffer is active, it returns @code{nil}. | |
2216 | @end defun | |
2217 | ||
2218 | @defun minibuffer-prompt-end | |
2219 | This function returns the current | |
2220 | position of the end of the minibuffer prompt, if a minibuffer is | |
2221 | current. Otherwise, it returns the minimum valid buffer position. | |
2222 | @end defun | |
2223 | ||
2224 | @defun minibuffer-prompt-width | |
2225 | This function returns the current display-width of the minibuffer | |
2226 | prompt, if a minibuffer is current. Otherwise, it returns zero. | |
2227 | @end defun | |
2228 | ||
2229 | @defun minibuffer-contents | |
2230 | This function returns the editable | |
2231 | contents of the minibuffer (that is, everything except the prompt) as | |
2232 | a string, if a minibuffer is current. Otherwise, it returns the | |
2233 | entire contents of the current buffer. | |
2234 | @end defun | |
2235 | ||
2236 | @defun minibuffer-contents-no-properties | |
2237 | This is like @code{minibuffer-contents}, except that it does not copy text | |
2238 | properties, just the characters themselves. @xref{Text Properties}. | |
2239 | @end defun | |
2240 | ||
2241 | @defun minibuffer-completion-contents | |
2242 | This is like @code{minibuffer-contents}, except that it returns only | |
2243 | the contents before point. That is the part that completion commands | |
2244 | operate on. @xref{Minibuffer Completion}. | |
2245 | @end defun | |
2246 | ||
2247 | @defun delete-minibuffer-contents | |
2248 | This function erases the editable contents of the minibuffer (that is, | |
2249 | everything except the prompt), if a minibuffer is current. Otherwise, | |
2250 | it erases the entire current buffer. | |
2251 | @end defun | |
2252 | ||
2253 | @node Recursive Mini | |
2254 | @section Recursive Minibuffers | |
2255 | @cindex recursive minibuffers | |
2256 | ||
2257 | These functions and variables deal with recursive minibuffers | |
2258 | (@pxref{Recursive Editing}): | |
2259 | ||
2260 | @defun minibuffer-depth | |
2261 | This function returns the current depth of activations of the | |
2262 | minibuffer, a nonnegative integer. If no minibuffers are active, it | |
2263 | returns zero. | |
2264 | @end defun | |
2265 | ||
2266 | @defopt enable-recursive-minibuffers | |
2267 | If this variable is non-@code{nil}, you can invoke commands (such as | |
2268 | @code{find-file}) that use minibuffers even while the minibuffer window | |
2269 | is active. Such invocation produces a recursive editing level for a new | |
2270 | minibuffer. The outer-level minibuffer is invisible while you are | |
2271 | editing the inner one. | |
2272 | ||
2273 | If this variable is @code{nil}, you cannot invoke minibuffer | |
2274 | commands when the minibuffer window is active, not even if you switch to | |
2275 | another window to do it. | |
2276 | @end defopt | |
2277 | ||
2278 | @c Emacs 19 feature | |
2279 | If a command name has a property @code{enable-recursive-minibuffers} | |
2280 | that is non-@code{nil}, then the command can use the minibuffer to read | |
2281 | arguments even if it is invoked from the minibuffer. A command can | |
2282 | also achieve this by binding @code{enable-recursive-minibuffers} | |
2283 | to @code{t} in the interactive declaration (@pxref{Using Interactive}). | |
2284 | The minibuffer command @code{next-matching-history-element} (normally | |
2285 | @kbd{M-s} in the minibuffer) does the latter. | |
2286 | ||
2287 | @node Minibuffer Misc | |
2288 | @section Minibuffer Miscellany | |
2289 | ||
2290 | @defun minibufferp &optional buffer-or-name | |
2291 | This function returns non-@code{nil} if @var{buffer-or-name} is a | |
2292 | minibuffer. If @var{buffer-or-name} is omitted, it tests the current | |
2293 | buffer. | |
2294 | @end defun | |
2295 | ||
2296 | @defvar minibuffer-setup-hook | |
2297 | This is a normal hook that is run whenever the minibuffer is entered. | |
2298 | @xref{Hooks}. | |
2299 | @end defvar | |
2300 | ||
2301 | @defvar minibuffer-exit-hook | |
2302 | This is a normal hook that is run whenever the minibuffer is exited. | |
2303 | @xref{Hooks}. | |
2304 | @end defvar | |
2305 | ||
2306 | @defvar minibuffer-help-form | |
2307 | @anchor{Definition of minibuffer-help-form} | |
2308 | The current value of this variable is used to rebind @code{help-form} | |
2309 | locally inside the minibuffer (@pxref{Help Functions}). | |
2310 | @end defvar | |
2311 | ||
2312 | @defvar minibuffer-scroll-window | |
2313 | @anchor{Definition of minibuffer-scroll-window} | |
2314 | If the value of this variable is non-@code{nil}, it should be a window | |
2315 | object. When the function @code{scroll-other-window} is called in the | |
2316 | minibuffer, it scrolls this window. | |
2317 | @end defvar | |
2318 | ||
2319 | @defun minibuffer-selected-window | |
c0ea08d2 | 2320 | This function returns the window that was selected when the |
b8d4c8d0 GM |
2321 | minibuffer was entered. If selected window is not a minibuffer |
2322 | window, it returns @code{nil}. | |
2323 | @end defun | |
2324 | ||
2325 | @defopt max-mini-window-height | |
2326 | This variable specifies the maximum height for resizing minibuffer | |
2327 | windows. If a float, it specifies a fraction of the height of the | |
2328 | frame. If an integer, it specifies a number of lines. | |
2329 | @end defopt | |
2330 | ||
c0ea08d2 | 2331 | @vindex minibuffer-message-timeout |
106e6894 | 2332 | @defun minibuffer-message string &rest args |
b8d4c8d0 | 2333 | This function displays @var{string} temporarily at the end of the |
c0ea08d2 GM |
2334 | minibuffer text, for a few seconds, or until the next input event |
2335 | arrives, whichever comes first. The variable | |
2336 | @code{minibuffer-message-timeout} specifies the number of seconds to | |
2337 | wait in the absence of input. It defaults to 2. If @var{args} is | |
2338 | non-@code{nil}, the actual message is obtained by passing @var{string} | |
2339 | and @var{args} through @code{format}. @xref{Formatting Strings}. | |
b8d4c8d0 | 2340 | @end defun |
c0ea08d2 GM |
2341 | |
2342 | @deffn Command minibuffer-inactive-mode | |
2343 | This is the major mode used in inactive minibuffers. It uses | |
2344 | keymap @code{minibuffer-inactive-mode-map}. This can be useful | |
2345 | if the minibuffer is in a separate frame. @xref{Minibuffers and Frames}. | |
2346 | @end deffn |