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1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
ba318903 | 3 | @c Copyright (C) 1990-1995, 1998-1999, 2001-2014 Free Software |
ab422c4d | 4 | @c Foundation, Inc. |
b8d4c8d0 | 5 | @c See the file elisp.texi for copying conditions. |
ecc6530d | 6 | @node Minibuffers |
b8d4c8d0 GM |
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 | ||
cd996018 | 214 | @defun read-regexp prompt &optional default history |
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 | |
cd996018 | 217 | @code{read-from-minibuffer}. |
6d4913f0 | 218 | |
9d2754f5 | 219 | The optional argument @var{default} specifies a default value to |
2ee797be | 220 | return if the user enters null input; it should be a string, or |
9d2754f5 | 221 | @code{nil}, which is equivalent to an empty string. |
2ee797be | 222 | |
cd996018 CY |
223 | The optional argument @var{history}, if non-@code{nil}, is a symbol |
224 | specifying a minibuffer history list to use (@pxref{Minibuffer | |
225 | History}). If it is omitted or @code{nil}, the history list defaults | |
226 | to @code{regexp-history}. | |
227 | ||
228 | @code{read-regexp} also collects a few useful candidates for input and | |
229 | passes them to @code{read-from-minibuffer}, to make them available to | |
230 | the user as the ``future minibuffer history list'' (@pxref{Minibuffer | |
231 | History, future list,, emacs, The GNU Emacs Manual}). These | |
232 | candidates are: | |
6d4913f0 EZ |
233 | |
234 | @itemize @minus | |
235 | @item | |
56b00ec7 | 236 | The word or symbol at point. |
6d4913f0 EZ |
237 | @item |
238 | The last regexp used in an incremental search. | |
239 | @item | |
240 | The last string used in an incremental search. | |
241 | @item | |
242 | The last string or pattern used in query-replace commands. | |
243 | @end itemize | |
244 | ||
245 | This function works by calling the @code{read-from-minibuffer} | |
246 | function, after computing the list of defaults as described above. | |
247 | @end defun | |
248 | ||
b8d4c8d0 | 249 | @defvar minibuffer-allow-text-properties |
9d2754f5 GM |
250 | If this variable is @code{nil}, then @code{read-from-minibuffer} |
251 | and @code{read-string} strip all text properties from the minibuffer | |
252 | input before returning it. However, | |
b8d4c8d0 GM |
253 | @code{read-no-blanks-input} (see below), as well as |
254 | @code{read-minibuffer} and related functions (@pxref{Object from | |
255 | Minibuffer,, Reading Lisp Objects With the Minibuffer}), and all | |
256 | functions that do minibuffer input with completion, discard text | |
257 | properties unconditionally, regardless of the value of this variable. | |
258 | @end defvar | |
259 | ||
260 | @defvar minibuffer-local-map | |
261 | This | |
262 | @anchor{Definition of minibuffer-local-map} | |
263 | @c avoid page break at anchor; work around Texinfo deficiency | |
264 | is the default local keymap for reading from the minibuffer. By | |
265 | default, it makes the following bindings: | |
266 | ||
267 | @table @asis | |
268 | @item @kbd{C-j} | |
269 | @code{exit-minibuffer} | |
270 | ||
271 | @item @key{RET} | |
272 | @code{exit-minibuffer} | |
273 | ||
274 | @item @kbd{C-g} | |
275 | @code{abort-recursive-edit} | |
276 | ||
277 | @item @kbd{M-n} | |
278 | @itemx @key{DOWN} | |
279 | @code{next-history-element} | |
280 | ||
281 | @item @kbd{M-p} | |
282 | @itemx @key{UP} | |
283 | @code{previous-history-element} | |
284 | ||
285 | @item @kbd{M-s} | |
286 | @code{next-matching-history-element} | |
287 | ||
288 | @item @kbd{M-r} | |
289 | @code{previous-matching-history-element} | |
9d2754f5 GM |
290 | |
291 | @ignore | |
292 | @c Does not seem worth/appropriate mentioning. | |
293 | @item @kbd{C-@key{TAB}} | |
294 | @code{file-cache-minibuffer-complete} | |
295 | @end ignore | |
b8d4c8d0 GM |
296 | @end table |
297 | @end defvar | |
298 | ||
299 | @c In version 18, initial is required | |
300 | @c Emacs 19 feature | |
301 | @defun read-no-blanks-input prompt &optional initial inherit-input-method | |
302 | This function reads a string from the minibuffer, but does not allow | |
303 | whitespace characters as part of the input: instead, those characters | |
304 | terminate the input. The arguments @var{prompt}, @var{initial}, and | |
305 | @var{inherit-input-method} are used as in @code{read-from-minibuffer}. | |
306 | ||
307 | This is a simplified interface to the @code{read-from-minibuffer} | |
308 | function, and passes the value of the @code{minibuffer-local-ns-map} | |
309 | keymap as the @var{keymap} argument for that function. Since the keymap | |
310 | @code{minibuffer-local-ns-map} does not rebind @kbd{C-q}, it @emph{is} | |
311 | possible to put a space into the string, by quoting it. | |
312 | ||
313 | This function discards text properties, regardless of the value of | |
314 | @code{minibuffer-allow-text-properties}. | |
315 | ||
316 | @smallexample | |
317 | @group | |
318 | (read-no-blanks-input @var{prompt} @var{initial}) | |
319 | @equiv{} | |
320 | (let (minibuffer-allow-text-properties) | |
321 | (read-from-minibuffer @var{prompt} @var{initial} minibuffer-local-ns-map)) | |
322 | @end group | |
323 | @end smallexample | |
324 | @end defun | |
325 | ||
9d2754f5 GM |
326 | @c Slightly unfortunate name, suggesting it might be related to the |
327 | @c Nextstep port... | |
b8d4c8d0 GM |
328 | @defvar minibuffer-local-ns-map |
329 | This built-in variable is the keymap used as the minibuffer local keymap | |
330 | in the function @code{read-no-blanks-input}. By default, it makes the | |
331 | following bindings, in addition to those of @code{minibuffer-local-map}: | |
332 | ||
333 | @table @asis | |
334 | @item @key{SPC} | |
335 | @cindex @key{SPC} in minibuffer | |
336 | @code{exit-minibuffer} | |
337 | ||
338 | @item @key{TAB} | |
339 | @cindex @key{TAB} in minibuffer | |
340 | @code{exit-minibuffer} | |
341 | ||
342 | @item @kbd{?} | |
343 | @cindex @kbd{?} in minibuffer | |
344 | @code{self-insert-and-exit} | |
345 | @end table | |
346 | @end defvar | |
347 | ||
348 | @node Object from Minibuffer | |
349 | @section Reading Lisp Objects with the Minibuffer | |
350 | ||
351 | This section describes functions for reading Lisp objects with the | |
352 | minibuffer. | |
353 | ||
354 | @defun read-minibuffer prompt &optional initial | |
355 | This function reads a Lisp object using the minibuffer, and returns it | |
356 | without evaluating it. The arguments @var{prompt} and @var{initial} are | |
357 | used as in @code{read-from-minibuffer}. | |
358 | ||
359 | This is a simplified interface to the | |
360 | @code{read-from-minibuffer} function: | |
361 | ||
362 | @smallexample | |
363 | @group | |
364 | (read-minibuffer @var{prompt} @var{initial}) | |
365 | @equiv{} | |
366 | (let (minibuffer-allow-text-properties) | |
367 | (read-from-minibuffer @var{prompt} @var{initial} nil t)) | |
368 | @end group | |
369 | @end smallexample | |
370 | ||
371 | Here is an example in which we supply the string @code{"(testing)"} as | |
372 | initial input: | |
373 | ||
374 | @smallexample | |
375 | @group | |
376 | (read-minibuffer | |
377 | "Enter an expression: " (format "%s" '(testing))) | |
378 | ||
379 | ;; @r{Here is how the minibuffer is displayed:} | |
380 | @end group | |
381 | ||
382 | @group | |
383 | ---------- Buffer: Minibuffer ---------- | |
384 | Enter an expression: (testing)@point{} | |
385 | ---------- Buffer: Minibuffer ---------- | |
386 | @end group | |
387 | @end smallexample | |
388 | ||
389 | @noindent | |
390 | The user can type @key{RET} immediately to use the initial input as a | |
391 | default, or can edit the input. | |
392 | @end defun | |
393 | ||
394 | @defun eval-minibuffer prompt &optional initial | |
395 | This function reads a Lisp expression using the minibuffer, evaluates | |
396 | it, then returns the result. The arguments @var{prompt} and | |
397 | @var{initial} are used as in @code{read-from-minibuffer}. | |
398 | ||
399 | This function simply evaluates the result of a call to | |
400 | @code{read-minibuffer}: | |
401 | ||
402 | @smallexample | |
403 | @group | |
404 | (eval-minibuffer @var{prompt} @var{initial}) | |
405 | @equiv{} | |
406 | (eval (read-minibuffer @var{prompt} @var{initial})) | |
407 | @end group | |
408 | @end smallexample | |
409 | @end defun | |
410 | ||
411 | @defun edit-and-eval-command prompt form | |
c0ea08d2 GM |
412 | This function reads a Lisp expression in the minibuffer, evaluates it, |
413 | then returns the result. The difference between this command and | |
b8d4c8d0 GM |
414 | @code{eval-minibuffer} is that here the initial @var{form} is not |
415 | optional and it is treated as a Lisp object to be converted to printed | |
416 | representation rather than as a string of text. It is printed with | |
417 | @code{prin1}, so if it is a string, double-quote characters (@samp{"}) | |
418 | appear in the initial text. @xref{Output Functions}. | |
419 | ||
b8d4c8d0 | 420 | In the following example, we offer the user an expression with initial |
c0ea08d2 | 421 | text that is already a valid form: |
b8d4c8d0 GM |
422 | |
423 | @smallexample | |
424 | @group | |
425 | (edit-and-eval-command "Please edit: " '(forward-word 1)) | |
426 | ||
427 | ;; @r{After evaluation of the preceding expression,} | |
428 | ;; @r{the following appears in the minibuffer:} | |
429 | @end group | |
430 | ||
431 | @group | |
432 | ---------- Buffer: Minibuffer ---------- | |
433 | Please edit: (forward-word 1)@point{} | |
434 | ---------- Buffer: Minibuffer ---------- | |
435 | @end group | |
436 | @end smallexample | |
437 | ||
438 | @noindent | |
439 | Typing @key{RET} right away would exit the minibuffer and evaluate the | |
440 | expression, thus moving point forward one word. | |
b8d4c8d0 GM |
441 | @end defun |
442 | ||
443 | @node Minibuffer History | |
444 | @section Minibuffer History | |
445 | @cindex minibuffer history | |
446 | @cindex history list | |
447 | ||
b923f7a9 CY |
448 | A @dfn{minibuffer history list} records previous minibuffer inputs |
449 | so the user can reuse them conveniently. It is a variable whose value | |
450 | is a list of strings (previous inputs), most recent first. | |
451 | ||
452 | There are many separate minibuffer history lists, used for different | |
453 | kinds of inputs. It's the Lisp programmer's job to specify the right | |
454 | history list for each use of the minibuffer. | |
455 | ||
9d2754f5 | 456 | You specify a minibuffer history list with the optional @var{history} |
b923f7a9 CY |
457 | argument to @code{read-from-minibuffer} or @code{completing-read}. |
458 | Here are the possible values for it: | |
b8d4c8d0 GM |
459 | |
460 | @table @asis | |
461 | @item @var{variable} | |
462 | Use @var{variable} (a symbol) as the history list. | |
463 | ||
464 | @item (@var{variable} . @var{startpos}) | |
465 | Use @var{variable} (a symbol) as the history list, and assume that the | |
466 | initial history position is @var{startpos} (a nonnegative integer). | |
467 | ||
468 | Specifying 0 for @var{startpos} is equivalent to just specifying the | |
469 | symbol @var{variable}. @code{previous-history-element} will display | |
470 | the most recent element of the history list in the minibuffer. If you | |
471 | specify a positive @var{startpos}, the minibuffer history functions | |
9d2754f5 | 472 | behave as if @code{(elt @var{variable} (1- @var{startpos}))} were the |
b8d4c8d0 GM |
473 | history element currently shown in the minibuffer. |
474 | ||
475 | For consistency, you should also specify that element of the history | |
476 | as the initial minibuffer contents, using the @var{initial} argument | |
477 | to the minibuffer input function (@pxref{Initial Input}). | |
478 | @end table | |
479 | ||
9d2754f5 | 480 | If you don't specify @var{history}, then the default history list |
b8d4c8d0 GM |
481 | @code{minibuffer-history} is used. For other standard history lists, |
482 | see below. You can also create your own history list variable; just | |
483 | initialize it to @code{nil} before the first use. | |
484 | ||
485 | Both @code{read-from-minibuffer} and @code{completing-read} add new | |
486 | elements to the history list automatically, and provide commands to | |
487 | allow the user to reuse items on the list. The only thing your program | |
488 | needs to do to use a history list is to initialize it and to pass its | |
489 | name to the input functions when you wish. But it is safe to modify the | |
490 | list by hand when the minibuffer input functions are not using it. | |
491 | ||
492 | Emacs functions that add a new element to a history list can also | |
493 | delete old elements if the list gets too long. The variable | |
494 | @code{history-length} specifies the maximum length for most history | |
495 | lists. To specify a different maximum length for a particular history | |
496 | list, put the length in the @code{history-length} property of the | |
497 | history list symbol. The variable @code{history-delete-duplicates} | |
498 | specifies whether to delete duplicates in history. | |
499 | ||
500 | @defun add-to-history history-var newelt &optional maxelt keep-all | |
501 | This function adds a new element @var{newelt}, if it isn't the empty | |
502 | string, to the history list stored in the variable @var{history-var}, | |
503 | and returns the updated history list. It limits the list length to | |
504 | the value of @var{maxelt} (if non-@code{nil}) or @code{history-length} | |
505 | (described below). The possible values of @var{maxelt} have the same | |
506 | meaning as the values of @code{history-length}. | |
507 | ||
508 | Normally, @code{add-to-history} removes duplicate members from the | |
509 | history list if @code{history-delete-duplicates} is non-@code{nil}. | |
510 | However, if @var{keep-all} is non-@code{nil}, that says not to remove | |
511 | duplicates, and to add @var{newelt} to the list even if it is empty. | |
512 | @end defun | |
513 | ||
514 | @defvar history-add-new-input | |
515 | If the value of this variable is @code{nil}, standard functions that | |
516 | read from the minibuffer don't add new elements to the history list. | |
517 | This lets Lisp programs explicitly manage input history by using | |
e68b393e | 518 | @code{add-to-history}. The default value is @code{t}. |
b8d4c8d0 GM |
519 | @end defvar |
520 | ||
01f17ae2 | 521 | @defopt history-length |
b8d4c8d0 GM |
522 | The value of this variable specifies the maximum length for all |
523 | history lists that don't specify their own maximum lengths. If the | |
da0bbbc4 | 524 | value is @code{t}, that means there is no maximum (don't delete old |
c0ea08d2 GM |
525 | elements). If a history list variable's symbol has a non-@code{nil} |
526 | @code{history-length} property, it overrides this variable for that | |
b8d4c8d0 | 527 | particular history list. |
01f17ae2 | 528 | @end defopt |
b8d4c8d0 | 529 | |
01f17ae2 | 530 | @defopt history-delete-duplicates |
b8d4c8d0 GM |
531 | If the value of this variable is @code{t}, that means when adding a |
532 | new history element, all previous identical elements are deleted. | |
01f17ae2 | 533 | @end defopt |
b8d4c8d0 GM |
534 | |
535 | Here are some of the standard minibuffer history list variables: | |
536 | ||
537 | @defvar minibuffer-history | |
538 | The default history list for minibuffer history input. | |
539 | @end defvar | |
540 | ||
541 | @defvar query-replace-history | |
542 | A history list for arguments to @code{query-replace} (and similar | |
543 | arguments to other commands). | |
544 | @end defvar | |
545 | ||
546 | @defvar file-name-history | |
547 | A history list for file-name arguments. | |
548 | @end defvar | |
549 | ||
550 | @defvar buffer-name-history | |
551 | A history list for buffer-name arguments. | |
552 | @end defvar | |
553 | ||
554 | @defvar regexp-history | |
555 | A history list for regular expression arguments. | |
556 | @end defvar | |
557 | ||
558 | @defvar extended-command-history | |
559 | A history list for arguments that are names of extended commands. | |
560 | @end defvar | |
561 | ||
562 | @defvar shell-command-history | |
563 | A history list for arguments that are shell commands. | |
564 | @end defvar | |
565 | ||
566 | @defvar read-expression-history | |
567 | A history list for arguments that are Lisp expressions to evaluate. | |
568 | @end defvar | |
569 | ||
c0ea08d2 GM |
570 | @defvar face-name-history |
571 | A history list for arguments that are faces. | |
572 | @end defvar | |
573 | ||
574 | @c Less common: coding-system-history, input-method-history, | |
575 | @c command-history, grep-history, grep-find-history, | |
576 | @c read-envvar-name-history, setenv-history, yes-or-no-p-history. | |
577 | ||
b8d4c8d0 GM |
578 | @node Initial Input |
579 | @section Initial Input | |
580 | ||
581 | Several of the functions for minibuffer input have an argument called | |
9d2754f5 | 582 | @var{initial}. This is a mostly-deprecated |
b8d4c8d0 GM |
583 | feature for specifying that the minibuffer should start out with |
584 | certain text, instead of empty as usual. | |
585 | ||
586 | If @var{initial} is a string, the minibuffer starts out containing the | |
587 | text of the string, with point at the end, when the user starts to | |
588 | edit the text. If the user simply types @key{RET} to exit the | |
589 | minibuffer, it will use the initial input string to determine the | |
590 | value to return. | |
591 | ||
592 | @strong{We discourage use of a non-@code{nil} value for | |
593 | @var{initial}}, because initial input is an intrusive interface. | |
594 | History lists and default values provide a much more convenient method | |
595 | to offer useful default inputs to the user. | |
596 | ||
597 | There is just one situation where you should specify a string for an | |
598 | @var{initial} argument. This is when you specify a cons cell for the | |
9d2754f5 | 599 | @var{history} argument. @xref{Minibuffer History}. |
b8d4c8d0 GM |
600 | |
601 | @var{initial} can also be a cons cell of the form @code{(@var{string} | |
602 | . @var{position})}. This means to insert @var{string} in the | |
603 | minibuffer but put point at @var{position} within the string's text. | |
604 | ||
605 | As a historical accident, @var{position} was implemented | |
606 | inconsistently in different functions. In @code{completing-read}, | |
607 | @var{position}'s value is interpreted as origin-zero; that is, a value | |
608 | of 0 means the beginning of the string, 1 means after the first | |
609 | character, etc. In @code{read-minibuffer}, and the other | |
610 | non-completion minibuffer input functions that support this argument, | |
c0ea08d2 | 611 | 1 means the beginning of the string, 2 means after the first character, |
b8d4c8d0 GM |
612 | etc. |
613 | ||
c0ea08d2 | 614 | Use of a cons cell as the value for @var{initial} arguments is deprecated. |
b8d4c8d0 GM |
615 | |
616 | @node Completion | |
617 | @section Completion | |
618 | @cindex completion | |
619 | ||
620 | @dfn{Completion} is a feature that fills in the rest of a name | |
621 | starting from an abbreviation for it. Completion works by comparing the | |
622 | user's input against a list of valid names and determining how much of | |
623 | the name is determined uniquely by what the user has typed. For | |
624 | example, when you type @kbd{C-x b} (@code{switch-to-buffer}) and then | |
b58b1df8 | 625 | @c "This is the sort of English up with which I will not put." |
b8d4c8d0 GM |
626 | type the first few letters of the name of the buffer to which you wish |
627 | to switch, and then type @key{TAB} (@code{minibuffer-complete}), Emacs | |
628 | extends the name as far as it can. | |
629 | ||
630 | Standard Emacs commands offer completion for names of symbols, files, | |
631 | buffers, and processes; with the functions in this section, you can | |
632 | implement completion for other kinds of names. | |
633 | ||
634 | The @code{try-completion} function is the basic primitive for | |
635 | completion: it returns the longest determined completion of a given | |
636 | initial string, with a given set of strings to match against. | |
637 | ||
638 | The function @code{completing-read} provides a higher-level interface | |
639 | for completion. A call to @code{completing-read} specifies how to | |
640 | determine the list of valid names. The function then activates the | |
641 | minibuffer with a local keymap that binds a few keys to commands useful | |
642 | for completion. Other functions provide convenient simple interfaces | |
643 | for reading certain kinds of names with completion. | |
644 | ||
645 | @menu | |
646 | * Basic Completion:: Low-level functions for completing strings. | |
b8d4c8d0 GM |
647 | * Minibuffer Completion:: Invoking the minibuffer with completion. |
648 | * Completion Commands:: Minibuffer commands that do completion. | |
649 | * High-Level Completion:: Convenient special cases of completion | |
b58b1df8 | 650 | (reading buffer names, variable names, etc.). |
e4372165 EZ |
651 | * Reading File Names:: Using completion to read file names and |
652 | shell commands. | |
321cc491 CY |
653 | * Completion Variables:: Variables controlling completion behavior. |
654 | * Programmed Completion:: Writing your own completion function. | |
60236b0d | 655 | * Completion in Buffers:: Completing text in ordinary buffers. |
b8d4c8d0 GM |
656 | @end menu |
657 | ||
658 | @node Basic Completion | |
659 | @subsection Basic Completion Functions | |
660 | ||
eb5ed549 CY |
661 | The following completion functions have nothing in themselves to do |
662 | with minibuffers. We describe them here to keep them near the | |
663 | higher-level completion features that do use the minibuffer. | |
b8d4c8d0 GM |
664 | |
665 | @defun try-completion string collection &optional predicate | |
666 | This function returns the longest common substring of all possible | |
60236b0d CY |
667 | completions of @var{string} in @var{collection}. |
668 | ||
669 | @cindex completion table | |
379acb95 CY |
670 | @var{collection} is called the @dfn{completion table}. Its value must |
671 | be a list of strings or cons cells, an obarray, a hash table, or a | |
672 | completion function. | |
673 | ||
674 | @code{try-completion} compares @var{string} against each of the | |
675 | permissible completions specified by the completion table. If no | |
676 | permissible completions match, it returns @code{nil}. If there is | |
677 | just one matching completion, and the match is exact, it returns | |
eb5ed549 CY |
678 | @code{t}. Otherwise, it returns the longest initial sequence common |
679 | to all possible matching completions. | |
b8d4c8d0 | 680 | |
379acb95 CY |
681 | If @var{collection} is an list, the permissible completions are |
682 | specified by the elements of the list, each of which should be either | |
683 | a string, or a cons cell whose @sc{car} is either a string or a symbol | |
684 | (a symbol is converted to a string using @code{symbol-name}). If the | |
685 | list contains elements of any other type, those are ignored. | |
b8d4c8d0 GM |
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}) | |
1df7defd | 775 | are the same as those of @code{try-completion}, and it |
b58b1df8 | 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 | ||
a045a167 | 889 | @c FIXME? completion-table-with-context? |
a045a167 GM |
890 | @findex completion-table-case-fold |
891 | @findex completion-table-in-turn | |
892 | @findex completion-table-subvert | |
7f6705c3 | 893 | @findex completion-table-with-quoting |
a045a167 GM |
894 | @findex completion-table-with-predicate |
895 | @findex completion-table-with-terminator | |
e3369c41 GM |
896 | @cindex completion table, modifying |
897 | @cindex completion tables, combining | |
a045a167 GM |
898 | There are several functions that take an existing completion table and |
899 | return a modified version. @code{completion-table-case-fold} returns | |
900 | a case-insensitive table. @code{completion-table-in-turn} combines | |
901 | multiple input tables. @code{completion-table-subvert} alters a table | |
7f6705c3 GM |
902 | to use a different initial prefix. @code{completion-table-with-quoting} |
903 | returns a table suitable for operating on quoted text. | |
a045a167 | 904 | @code{completion-table-with-predicate} filters a table with a |
7f6705c3 GM |
905 | predicate function. @code{completion-table-with-terminator} adds a |
906 | terminating string. | |
a045a167 GM |
907 | |
908 | ||
b8d4c8d0 GM |
909 | @node Minibuffer Completion |
910 | @subsection Completion and the Minibuffer | |
911 | @cindex minibuffer completion | |
912 | @cindex reading from minibuffer with completion | |
913 | ||
914 | This section describes the basic interface for reading from the | |
915 | minibuffer with completion. | |
916 | ||
9d2754f5 | 917 | @defun completing-read prompt collection &optional predicate require-match initial history default inherit-input-method |
b8d4c8d0 GM |
918 | This function reads a string in the minibuffer, assisting the user by |
919 | providing completion. It activates the minibuffer with prompt | |
920 | @var{prompt}, which must be a string. | |
921 | ||
60236b0d CY |
922 | The actual completion is done by passing the completion table |
923 | @var{collection} and the completion predicate @var{predicate} to the | |
924 | function @code{try-completion} (@pxref{Basic Completion}). This | |
925 | happens in certain commands bound in the local keymaps used for | |
926 | completion. Some of these commands also call @code{test-completion}. | |
927 | Thus, if @var{predicate} is non-@code{nil}, it should be compatible | |
928 | with @var{collection} and @code{completion-ignore-case}. | |
929 | @xref{Definition of test-completion}. | |
b8d4c8d0 | 930 | |
b613b1dc CY |
931 | The value of the optional argument @var{require-match} determines how |
932 | the user may exit the minibuffer: | |
933 | ||
934 | @itemize @bullet | |
935 | @item | |
936 | If @code{nil}, the usual minibuffer exit commands work regardless of | |
937 | the input in the minibuffer. | |
938 | ||
939 | @item | |
940 | If @code{t}, the usual minibuffer exit commands won't exit unless the | |
941 | input completes to an element of @var{collection}. | |
942 | ||
943 | @item | |
944 | If @code{confirm}, the user can exit with any input, but is asked for | |
945 | confirmation if the input is not an element of @var{collection}. | |
946 | ||
947 | @item | |
948 | If @code{confirm-after-completion}, the user can exit with any input, | |
949 | but is asked for confirmation if the preceding command was a | |
950 | completion command (i.e., one of the commands in | |
951 | @code{minibuffer-confirm-exit-commands}) and the resulting input is | |
952 | not an element of @var{collection}. @xref{Completion Commands}. | |
953 | ||
954 | @item | |
955 | Any other value of @var{require-match} behaves like @code{t}, except | |
956 | that the exit commands won't exit if it performs completion. | |
957 | @end itemize | |
b8d4c8d0 GM |
958 | |
959 | However, empty input is always permitted, regardless of the value of | |
c1d2409c RS |
960 | @var{require-match}; in that case, @code{completing-read} returns the |
961 | first element of @var{default}, if it is a list; @code{""}, if | |
70ee951b JL |
962 | @var{default} is @code{nil}; or @var{default}. The string or strings |
963 | in @var{default} are also available to the user through the history | |
c1d2409c | 964 | commands. |
b8d4c8d0 GM |
965 | |
966 | The function @code{completing-read} uses | |
967 | @code{minibuffer-local-completion-map} as the keymap if | |
968 | @var{require-match} is @code{nil}, and uses | |
969 | @code{minibuffer-local-must-match-map} if @var{require-match} is | |
970 | non-@code{nil}. @xref{Completion Commands}. | |
971 | ||
9d2754f5 | 972 | The argument @var{history} specifies which history list variable to use for |
b8d4c8d0 GM |
973 | saving the input and for minibuffer history commands. It defaults to |
974 | @code{minibuffer-history}. @xref{Minibuffer History}. | |
975 | ||
976 | The argument @var{initial} is mostly deprecated; we recommend using a | |
977 | non-@code{nil} value only in conjunction with specifying a cons cell | |
9d2754f5 | 978 | for @var{history}. @xref{Initial Input}. For default input, use |
b8d4c8d0 GM |
979 | @var{default} instead. |
980 | ||
981 | If the argument @var{inherit-input-method} is non-@code{nil}, then the | |
982 | minibuffer inherits the current input method (@pxref{Input | |
983 | Methods}) and the setting of @code{enable-multibyte-characters} | |
984 | (@pxref{Text Representations}) from whichever buffer was current before | |
985 | entering the minibuffer. | |
986 | ||
b58b1df8 | 987 | If the variable @code{completion-ignore-case} is |
b8d4c8d0 GM |
988 | non-@code{nil}, completion ignores case when comparing the input |
989 | against the possible matches. @xref{Basic Completion}. In this mode | |
990 | of operation, @var{predicate} must also ignore case, or you will get | |
991 | surprising results. | |
992 | ||
993 | Here's an example of using @code{completing-read}: | |
994 | ||
995 | @smallexample | |
996 | @group | |
997 | (completing-read | |
998 | "Complete a foo: " | |
999 | '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) | |
1000 | nil t "fo") | |
1001 | @end group | |
1002 | ||
1003 | @group | |
1004 | ;; @r{After evaluation of the preceding expression,} | |
1005 | ;; @r{the following appears in the minibuffer:} | |
1006 | ||
1007 | ---------- Buffer: Minibuffer ---------- | |
1008 | Complete a foo: fo@point{} | |
1009 | ---------- Buffer: Minibuffer ---------- | |
1010 | @end group | |
1011 | @end smallexample | |
1012 | ||
1013 | @noindent | |
1014 | If the user then types @kbd{@key{DEL} @key{DEL} b @key{RET}}, | |
1015 | @code{completing-read} returns @code{barfoo}. | |
1016 | ||
1017 | The @code{completing-read} function binds variables to pass | |
1018 | information to the commands that actually do completion. | |
1019 | They are described in the following section. | |
1020 | @end defun | |
1021 | ||
245d176b CY |
1022 | @defvar completing-read-function |
1023 | The value of this variable must be a function, which is called by | |
1024 | @code{completing-read} to actually do its work. It should accept the | |
1025 | same arguments as @code{completing-read}. This can be bound to a | |
1026 | different function to completely override the normal behavior of | |
1027 | @code{completing-read}. | |
1028 | @end defvar | |
1029 | ||
b8d4c8d0 GM |
1030 | @node Completion Commands |
1031 | @subsection Minibuffer Commands that Do Completion | |
1032 | ||
1033 | This section describes the keymaps, commands and user options used | |
b613b1dc | 1034 | in the minibuffer to do completion. |
b8d4c8d0 GM |
1035 | |
1036 | @defvar minibuffer-completion-table | |
60236b0d CY |
1037 | The value of this variable is the completion table used for completion |
1038 | in the minibuffer. This is the global variable that contains what | |
b8d4c8d0 | 1039 | @code{completing-read} passes to @code{try-completion}. It is used by |
60236b0d CY |
1040 | minibuffer completion commands such as |
1041 | @code{minibuffer-complete-word}. | |
b8d4c8d0 GM |
1042 | @end defvar |
1043 | ||
1044 | @defvar minibuffer-completion-predicate | |
1045 | This variable's value is the predicate that @code{completing-read} | |
1046 | passes to @code{try-completion}. The variable is also used by the other | |
1047 | minibuffer completion functions. | |
1048 | @end defvar | |
1049 | ||
1050 | @defvar minibuffer-completion-confirm | |
b613b1dc CY |
1051 | This variable determines whether Emacs asks for confirmation before |
1052 | exiting the minibuffer; @code{completing-read} binds this variable, | |
1053 | and the function @code{minibuffer-complete-and-exit} checks the value | |
1054 | before exiting. If the value is @code{nil}, confirmation is not | |
1055 | required. If the value is @code{confirm}, the user may exit with an | |
1056 | input that is not a valid completion alternative, but Emacs asks for | |
1057 | confirmation. If the value is @code{confirm-after-completion}, the | |
1058 | user may exit with an input that is not a valid completion | |
1059 | alternative, but Emacs asks for confirmation if the user submitted the | |
1060 | input right after any of the completion commands in | |
1061 | @code{minibuffer-confirm-exit-commands}. | |
1062 | @end defvar | |
1063 | ||
1064 | @defvar minibuffer-confirm-exit-commands | |
1065 | This variable holds a list of commands that cause Emacs to ask for | |
1066 | confirmation before exiting the minibuffer, if the @var{require-match} | |
1067 | argument to @code{completing-read} is @code{confirm-after-completion}. | |
1068 | The confirmation is requested if the user attempts to exit the | |
1069 | minibuffer immediately after calling any command in this list. | |
b8d4c8d0 GM |
1070 | @end defvar |
1071 | ||
1072 | @deffn Command minibuffer-complete-word | |
1073 | This function completes the minibuffer contents by at most a single | |
1074 | word. Even if the minibuffer contents have only one completion, | |
1075 | @code{minibuffer-complete-word} does not add any characters beyond the | |
1076 | first character that is not a word constituent. @xref{Syntax Tables}. | |
1077 | @end deffn | |
1078 | ||
1079 | @deffn Command minibuffer-complete | |
1080 | This function completes the minibuffer contents as far as possible. | |
1081 | @end deffn | |
1082 | ||
1083 | @deffn Command minibuffer-complete-and-exit | |
1084 | This function completes the minibuffer contents, and exits if | |
1085 | confirmation is not required, i.e., if | |
1086 | @code{minibuffer-completion-confirm} is @code{nil}. If confirmation | |
1087 | @emph{is} required, it is given by repeating this command | |
1088 | immediately---the command is programmed to work without confirmation | |
1089 | when run twice in succession. | |
1090 | @end deffn | |
1091 | ||
1092 | @deffn Command minibuffer-completion-help | |
1093 | This function creates a list of the possible completions of the | |
1094 | current minibuffer contents. It works by calling @code{all-completions} | |
1095 | using the value of the variable @code{minibuffer-completion-table} as | |
1096 | the @var{collection} argument, and the value of | |
1097 | @code{minibuffer-completion-predicate} as the @var{predicate} argument. | |
1098 | The list of completions is displayed as text in a buffer named | |
2bb0eca1 | 1099 | @file{*Completions*}. |
b8d4c8d0 GM |
1100 | @end deffn |
1101 | ||
1102 | @defun display-completion-list completions &optional common-substring | |
1103 | This function displays @var{completions} to the stream in | |
1104 | @code{standard-output}, usually a buffer. (@xref{Read and Print}, for more | |
1105 | information about streams.) The argument @var{completions} is normally | |
1106 | a list of completions just returned by @code{all-completions}, but it | |
1107 | does not have to be. Each element may be a symbol or a string, either | |
1108 | of which is simply printed. It can also be a list of two strings, | |
1109 | which is printed as if the strings were concatenated. The first of | |
1110 | the two strings is the actual completion, the second string serves as | |
1111 | annotation. | |
1112 | ||
1113 | The argument @var{common-substring} is the prefix that is common to | |
1114 | all the completions. With normal Emacs completion, it is usually the | |
1115 | same as the string that was completed. @code{display-completion-list} | |
1116 | uses this to highlight text in the completion list for better visual | |
1117 | feedback. This is not needed in the minibuffer; for minibuffer | |
1118 | completion, you can pass @code{nil}. | |
1119 | ||
b58b1df8 GM |
1120 | This function is called by @code{minibuffer-completion-help}. A |
1121 | common way to use it is together with | |
b8d4c8d0 GM |
1122 | @code{with-output-to-temp-buffer}, like this: |
1123 | ||
1124 | @example | |
1125 | (with-output-to-temp-buffer "*Completions*" | |
1126 | (display-completion-list | |
1127 | (all-completions (buffer-string) my-alist) | |
1128 | (buffer-string))) | |
1129 | @end example | |
1130 | @end defun | |
1131 | ||
1132 | @defopt completion-auto-help | |
1133 | If this variable is non-@code{nil}, the completion commands | |
1134 | automatically display a list of possible completions whenever nothing | |
1135 | can be completed because the next character is not uniquely determined. | |
1136 | @end defopt | |
1137 | ||
1138 | @defvar minibuffer-local-completion-map | |
1139 | @code{completing-read} uses this value as the local keymap when an | |
1140 | exact match of one of the completions is not required. By default, this | |
1141 | keymap makes the following bindings: | |
1142 | ||
1143 | @table @asis | |
1144 | @item @kbd{?} | |
1145 | @code{minibuffer-completion-help} | |
1146 | ||
1147 | @item @key{SPC} | |
1148 | @code{minibuffer-complete-word} | |
1149 | ||
1150 | @item @key{TAB} | |
1151 | @code{minibuffer-complete} | |
1152 | @end table | |
1153 | ||
1154 | @noindent | |
b58b1df8 | 1155 | and uses @code{minibuffer-local-map} as its parent keymap |
b8d4c8d0 GM |
1156 | (@pxref{Definition of minibuffer-local-map}). |
1157 | @end defvar | |
1158 | ||
1159 | @defvar minibuffer-local-must-match-map | |
1160 | @code{completing-read} uses this value as the local keymap when an | |
1161 | exact match of one of the completions is required. Therefore, no keys | |
1162 | are bound to @code{exit-minibuffer}, the command that exits the | |
1163 | minibuffer unconditionally. By default, this keymap makes the following | |
1164 | bindings: | |
1165 | ||
1166 | @table @asis | |
b8d4c8d0 GM |
1167 | @item @kbd{C-j} |
1168 | @code{minibuffer-complete-and-exit} | |
1169 | ||
1170 | @item @key{RET} | |
1171 | @code{minibuffer-complete-and-exit} | |
1172 | @end table | |
1173 | ||
1174 | @noindent | |
b58b1df8 | 1175 | and uses @code{minibuffer-local-completion-map} as its parent keymap. |
b8d4c8d0 GM |
1176 | @end defvar |
1177 | ||
1178 | @defvar minibuffer-local-filename-completion-map | |
b58b1df8 GM |
1179 | This is a sparse keymap that simply unbinds @key{SPC}; because |
1180 | filenames can contain spaces. The function @code{read-file-name} | |
1181 | combines this keymap with either @code{minibuffer-local-completion-map} | |
1182 | or @code{minibuffer-local-must-match-map}. | |
b8d4c8d0 GM |
1183 | @end defvar |
1184 | ||
b8d4c8d0 GM |
1185 | |
1186 | @node High-Level Completion | |
e4372165 | 1187 | @subsection High-Level Completion Functions |
b8d4c8d0 | 1188 | |
b58b1df8 | 1189 | This section describes the higher-level convenience functions for |
b8d4c8d0 GM |
1190 | reading certain sorts of names with completion. |
1191 | ||
1192 | In most cases, you should not call these functions in the middle of a | |
1193 | Lisp function. When possible, do all minibuffer input as part of | |
1194 | reading the arguments for a command, in the @code{interactive} | |
1195 | specification. @xref{Defining Commands}. | |
1196 | ||
b613b1dc | 1197 | @defun read-buffer prompt &optional default require-match |
b8d4c8d0 GM |
1198 | This function reads the name of a buffer and returns it as a string. |
1199 | The argument @var{default} is the default name to use, the value to | |
1200 | return if the user exits with an empty minibuffer. If non-@code{nil}, | |
c066bafa JL |
1201 | it should be a string, a list of strings, or a buffer. If it is |
1202 | a list, the default value is the first element of this list. It is | |
1203 | mentioned in the prompt, but is not inserted in the minibuffer as | |
1204 | initial input. | |
b8d4c8d0 GM |
1205 | |
1206 | The argument @var{prompt} should be a string ending with a colon and a | |
1207 | space. If @var{default} is non-@code{nil}, the function inserts it in | |
1208 | @var{prompt} before the colon to follow the convention for reading from | |
1209 | the minibuffer with a default value (@pxref{Programming Tips}). | |
1210 | ||
b613b1dc CY |
1211 | The optional argument @var{require-match} has the same meaning as in |
1212 | @code{completing-read}. @xref{Minibuffer Completion}. | |
b8d4c8d0 GM |
1213 | |
1214 | In the following example, the user enters @samp{minibuffer.t}, and | |
b613b1dc CY |
1215 | then types @key{RET}. The argument @var{require-match} is @code{t}, |
1216 | and the only buffer name starting with the given input is | |
b8d4c8d0 GM |
1217 | @samp{minibuffer.texi}, so that name is the value. |
1218 | ||
1219 | @example | |
1220 | (read-buffer "Buffer name: " "foo" t) | |
1221 | @group | |
1222 | ;; @r{After evaluation of the preceding expression,} | |
1223 | ;; @r{the following prompt appears,} | |
1224 | ;; @r{with an empty minibuffer:} | |
1225 | @end group | |
1226 | ||
1227 | @group | |
1228 | ---------- Buffer: Minibuffer ---------- | |
1229 | Buffer name (default foo): @point{} | |
1230 | ---------- Buffer: Minibuffer ---------- | |
1231 | @end group | |
1232 | ||
1233 | @group | |
1234 | ;; @r{The user types @kbd{minibuffer.t @key{RET}}.} | |
1235 | @result{} "minibuffer.texi" | |
1236 | @end group | |
1237 | @end example | |
1238 | @end defun | |
1239 | ||
01f17ae2 | 1240 | @defopt read-buffer-function |
05b621a6 CY |
1241 | This variable, if non-@code{nil}, specifies a function for reading |
1242 | buffer names. @code{read-buffer} calls this function instead of doing | |
1243 | its usual work, with the same arguments passed to @code{read-buffer}. | |
01f17ae2 | 1244 | @end defopt |
b8d4c8d0 | 1245 | |
01f17ae2 | 1246 | @defopt read-buffer-completion-ignore-case |
b613b1dc CY |
1247 | If this variable is non-@code{nil}, @code{read-buffer} ignores case |
1248 | when performing completion. | |
01f17ae2 | 1249 | @end defopt |
b613b1dc | 1250 | |
b8d4c8d0 GM |
1251 | @defun read-command prompt &optional default |
1252 | This function reads the name of a command and returns it as a Lisp | |
1253 | symbol. The argument @var{prompt} is used as in | |
1254 | @code{read-from-minibuffer}. Recall that a command is anything for | |
1255 | which @code{commandp} returns @code{t}, and a command name is a symbol | |
1256 | for which @code{commandp} returns @code{t}. @xref{Interactive Call}. | |
1257 | ||
1258 | The argument @var{default} specifies what to return if the user enters | |
c066bafa JL |
1259 | null input. It can be a symbol, a string or a list of strings. If it |
1260 | is a string, @code{read-command} interns it before returning it. | |
b58b1df8 | 1261 | If it is a list, @code{read-command} interns the first element of this list. |
c066bafa JL |
1262 | If @var{default} is @code{nil}, that means no default has been |
1263 | specified; then if the user enters null input, the return value is | |
1264 | @code{(intern "")}, that is, a symbol whose name is an empty string. | |
b8d4c8d0 GM |
1265 | |
1266 | @example | |
1267 | (read-command "Command name? ") | |
1268 | ||
1269 | @group | |
1270 | ;; @r{After evaluation of the preceding expression,} | |
1271 | ;; @r{the following prompt appears with an empty minibuffer:} | |
1272 | @end group | |
1273 | ||
1274 | @group | |
1275 | ---------- Buffer: Minibuffer ---------- | |
1276 | Command name? | |
1277 | ---------- Buffer: Minibuffer ---------- | |
1278 | @end group | |
1279 | @end example | |
1280 | ||
1281 | @noindent | |
1282 | If the user types @kbd{forward-c @key{RET}}, then this function returns | |
1283 | @code{forward-char}. | |
1284 | ||
1285 | The @code{read-command} function is a simplified interface to | |
1286 | @code{completing-read}. It uses the variable @code{obarray} so as to | |
1287 | complete in the set of extant Lisp symbols, and it uses the | |
1288 | @code{commandp} predicate so as to accept only command names: | |
1289 | ||
1290 | @cindex @code{commandp} example | |
1291 | @example | |
1292 | @group | |
1293 | (read-command @var{prompt}) | |
1294 | @equiv{} | |
1295 | (intern (completing-read @var{prompt} obarray | |
1296 | 'commandp t nil)) | |
1297 | @end group | |
1298 | @end example | |
1299 | @end defun | |
1300 | ||
1301 | @defun read-variable prompt &optional default | |
1302 | @anchor{Definition of read-variable} | |
c07a4c0b CY |
1303 | This function reads the name of a customizable variable and returns it |
1304 | as a symbol. Its arguments have the same form as those of | |
1305 | @code{read-command}. It behaves just like @code{read-command}, except | |
1306 | that it uses the predicate @code{custom-variable-p} instead of | |
1307 | @code{commandp}. | |
b8d4c8d0 GM |
1308 | @end defun |
1309 | ||
ef164dbc EZ |
1310 | @deffn Command read-color &optional prompt convert allow-empty display |
1311 | This function reads a string that is a color specification, either the | |
1312 | color's name or an RGB hex value such as @code{#RRRGGGBBB}. It | |
94bc7984 | 1313 | prompts with @var{prompt} (default: @code{"Color (name or #RGB triplet):"}) |
ef164dbc EZ |
1314 | and provides completion for color names, but not for hex RGB values. |
1315 | In addition to names of standard colors, completion candidates include | |
1316 | the foreground and background colors at point. | |
1317 | ||
1318 | Valid RGB values are described in @ref{Color Names}. | |
1319 | ||
94bc7984 | 1320 | The function's return value is the string typed by the user in the |
ef164dbc | 1321 | minibuffer. However, when called interactively or if the optional |
94bc7984 GM |
1322 | argument @var{convert} is non-@code{nil}, it converts any input color |
1323 | name into the corresponding RGB value string and instead returns that. | |
1324 | This function requires a valid color specification to be input. | |
b58b1df8 | 1325 | Empty color names are allowed when @var{allow-empty} is |
ef164dbc EZ |
1326 | non-@code{nil} and the user enters null input. |
1327 | ||
62e8099c | 1328 | Interactively, or when @var{display} is non-@code{nil}, the return |
ef164dbc EZ |
1329 | value is also displayed in the echo area. |
1330 | @end deffn | |
1331 | ||
b8d4c8d0 GM |
1332 | See also the functions @code{read-coding-system} and |
1333 | @code{read-non-nil-coding-system}, in @ref{User-Chosen Coding Systems}, | |
1334 | and @code{read-input-method-name}, in @ref{Input Methods}. | |
1335 | ||
1336 | @node Reading File Names | |
1337 | @subsection Reading File Names | |
1338 | @cindex read file names | |
1339 | @cindex prompt for file name | |
1340 | ||
62e8099c CY |
1341 | The high-level completion functions @code{read-file-name}, |
1342 | @code{read-directory-name}, and @code{read-shell-command} are designed | |
b58b1df8 | 1343 | to read file names, directory names, and shell commands, respectively. |
62e8099c CY |
1344 | They provide special features, including automatic insertion of the |
1345 | default directory. | |
b8d4c8d0 | 1346 | |
b613b1dc | 1347 | @defun read-file-name prompt &optional directory default require-match initial predicate |
0f063651 CY |
1348 | This function reads a file name, prompting with @var{prompt} and |
1349 | providing completion. | |
1350 | ||
1351 | As an exception, this function reads a file name using a graphical | |
b58b1df8 GM |
1352 | file dialog instead of the minibuffer, if all of the following are |
1353 | true: | |
1354 | ||
1355 | @enumerate | |
1356 | @item | |
1357 | It is invoked via a mouse command. | |
1358 | ||
1359 | @item | |
1360 | The selected frame is on a graphical display supporting such dialogs. | |
1361 | ||
1362 | @item | |
1363 | The variable @code{use-dialog-box} is non-@code{nil}. | |
1364 | @xref{Dialog Boxes,, Dialog Boxes, emacs, The GNU Emacs Manual}. | |
1365 | ||
1366 | @item | |
1367 | The @var{directory} argument, described below, does not specify a | |
1368 | remote file. @xref{Remote Files,, Remote Files, emacs, The GNU Emacs Manual}. | |
1369 | @end enumerate | |
1370 | ||
1371 | @noindent | |
1372 | The exact behavior when using a graphical file dialog is | |
1373 | platform-dependent. Here, we simply document the behavior when using | |
1374 | the minibuffer. | |
b8d4c8d0 | 1375 | |
b4d52acc CY |
1376 | @code{read-file-name} does not automatically expand the returned file |
1377 | name. You must call @code{expand-file-name} yourself if an absolute | |
1378 | file name is required. | |
b8d4c8d0 | 1379 | |
b4d52acc | 1380 | The optional argument @var{require-match} has the same meaning as in |
245d176b | 1381 | @code{completing-read}. @xref{Minibuffer Completion}. |
b8d4c8d0 GM |
1382 | |
1383 | The argument @var{directory} specifies the directory to use for | |
b4d52acc | 1384 | completing relative file names. It should be an absolute directory |
b58b1df8 | 1385 | name. If the variable @code{insert-default-directory} is non-@code{nil}, |
b8d4c8d0 GM |
1386 | @var{directory} is also inserted in the minibuffer as initial input. |
1387 | It defaults to the current buffer's value of @code{default-directory}. | |
1388 | ||
b8d4c8d0 GM |
1389 | If you specify @var{initial}, that is an initial file name to insert |
1390 | in the buffer (after @var{directory}, if that is inserted). In this | |
1391 | case, point goes at the beginning of @var{initial}. The default for | |
1392 | @var{initial} is @code{nil}---don't insert any file name. To see what | |
b58b1df8 GM |
1393 | @var{initial} does, try the command @kbd{C-x C-v} in a buffer visiting |
1394 | a file. @strong{Please note:} we recommend using @var{default} rather | |
1395 | than @var{initial} in most cases. | |
b8d4c8d0 GM |
1396 | |
1397 | If @var{default} is non-@code{nil}, then the function returns | |
1398 | @var{default} if the user exits the minibuffer with the same non-empty | |
1399 | contents that @code{read-file-name} inserted initially. The initial | |
1400 | minibuffer contents are always non-empty if | |
1401 | @code{insert-default-directory} is non-@code{nil}, as it is by | |
1402 | default. @var{default} is not checked for validity, regardless of the | |
b613b1dc | 1403 | value of @var{require-match}. However, if @var{require-match} is |
b8d4c8d0 GM |
1404 | non-@code{nil}, the initial minibuffer contents should be a valid file |
1405 | (or directory) name. Otherwise @code{read-file-name} attempts | |
1406 | completion if the user exits without any editing, and does not return | |
1407 | @var{default}. @var{default} is also available through the history | |
1408 | commands. | |
1409 | ||
1410 | If @var{default} is @code{nil}, @code{read-file-name} tries to find a | |
1411 | substitute default to use in its place, which it treats in exactly the | |
1412 | same way as if it had been specified explicitly. If @var{default} is | |
1413 | @code{nil}, but @var{initial} is non-@code{nil}, then the default is | |
1414 | the absolute file name obtained from @var{directory} and | |
1415 | @var{initial}. If both @var{default} and @var{initial} are @code{nil} | |
1416 | and the buffer is visiting a file, @code{read-file-name} uses the | |
1417 | absolute file name of that file as default. If the buffer is not | |
1418 | visiting a file, then there is no default. In that case, if the user | |
1419 | types @key{RET} without any editing, @code{read-file-name} simply | |
1420 | returns the pre-inserted contents of the minibuffer. | |
1421 | ||
1422 | If the user types @key{RET} in an empty minibuffer, this function | |
b613b1dc CY |
1423 | returns an empty string, regardless of the value of |
1424 | @var{require-match}. This is, for instance, how the user can make the | |
0b128ac4 | 1425 | current buffer visit no file using @kbd{M-x set-visited-file-name}. |
b8d4c8d0 GM |
1426 | |
1427 | If @var{predicate} is non-@code{nil}, it specifies a function of one | |
1428 | argument that decides which file names are acceptable completion | |
321cc491 | 1429 | alternatives. A file name is an acceptable value if @var{predicate} |
b8d4c8d0 GM |
1430 | returns non-@code{nil} for it. |
1431 | ||
b4d52acc | 1432 | Here is an example of using @code{read-file-name}: |
b8d4c8d0 GM |
1433 | |
1434 | @example | |
1435 | @group | |
1436 | (read-file-name "The file is ") | |
1437 | ||
1438 | ;; @r{After evaluation of the preceding expression,} | |
1439 | ;; @r{the following appears in the minibuffer:} | |
1440 | @end group | |
1441 | ||
1442 | @group | |
1443 | ---------- Buffer: Minibuffer ---------- | |
1444 | The file is /gp/gnu/elisp/@point{} | |
1445 | ---------- Buffer: Minibuffer ---------- | |
1446 | @end group | |
1447 | @end example | |
1448 | ||
1449 | @noindent | |
1450 | Typing @kbd{manual @key{TAB}} results in the following: | |
1451 | ||
1452 | @example | |
1453 | @group | |
1454 | ---------- Buffer: Minibuffer ---------- | |
1455 | The file is /gp/gnu/elisp/manual.texi@point{} | |
1456 | ---------- Buffer: Minibuffer ---------- | |
1457 | @end group | |
1458 | @end example | |
1459 | ||
1460 | @c Wordy to avoid overfull hbox in smallbook mode. | |
1461 | @noindent | |
1462 | If the user types @key{RET}, @code{read-file-name} returns the file name | |
1463 | as the string @code{"/gp/gnu/elisp/manual.texi"}. | |
1464 | @end defun | |
1465 | ||
1466 | @defvar read-file-name-function | |
1467 | If non-@code{nil}, this should be a function that accepts the same | |
1468 | arguments as @code{read-file-name}. When @code{read-file-name} is | |
1469 | called, it calls this function with the supplied arguments instead of | |
1470 | doing its usual work. | |
1471 | @end defvar | |
1472 | ||
01f17ae2 | 1473 | @defopt read-file-name-completion-ignore-case |
b8d4c8d0 GM |
1474 | If this variable is non-@code{nil}, @code{read-file-name} ignores case |
1475 | when performing completion. | |
01f17ae2 | 1476 | @end defopt |
b8d4c8d0 | 1477 | |
b613b1dc | 1478 | @defun read-directory-name prompt &optional directory default require-match initial |
b8d4c8d0 | 1479 | This function is like @code{read-file-name} but allows only directory |
321cc491 | 1480 | names as completion alternatives. |
b8d4c8d0 GM |
1481 | |
1482 | If @var{default} is @code{nil} and @var{initial} is non-@code{nil}, | |
1483 | @code{read-directory-name} constructs a substitute default by | |
1484 | combining @var{directory} (or the current buffer's default directory | |
1485 | if @var{directory} is @code{nil}) and @var{initial}. If both | |
1486 | @var{default} and @var{initial} are @code{nil}, this function uses | |
1487 | @var{directory} as substitute default, or the current buffer's default | |
1488 | directory if @var{directory} is @code{nil}. | |
1489 | @end defun | |
1490 | ||
1491 | @defopt insert-default-directory | |
1492 | This variable is used by @code{read-file-name}, and thus, indirectly, | |
1493 | by most commands reading file names. (This includes all commands that | |
1494 | use the code letters @samp{f} or @samp{F} in their interactive form. | |
1495 | @xref{Interactive Codes,, Code Characters for interactive}.) Its | |
1496 | value controls whether @code{read-file-name} starts by placing the | |
1497 | name of the default directory in the minibuffer, plus the initial file | |
b58b1df8 | 1498 | name, if any. If the value of this variable is @code{nil}, then |
b8d4c8d0 GM |
1499 | @code{read-file-name} does not place any initial input in the |
1500 | minibuffer (unless you specify initial input with the @var{initial} | |
1501 | argument). In that case, the default directory is still used for | |
1502 | completion of relative file names, but is not displayed. | |
1503 | ||
1504 | If this variable is @code{nil} and the initial minibuffer contents are | |
1505 | empty, the user may have to explicitly fetch the next history element | |
1506 | to access a default value. If the variable is non-@code{nil}, the | |
1507 | initial minibuffer contents are always non-empty and the user can | |
1508 | always request a default value by immediately typing @key{RET} in an | |
1509 | unedited minibuffer. (See above.) | |
1510 | ||
1511 | For example: | |
1512 | ||
1513 | @example | |
1514 | @group | |
1515 | ;; @r{Here the minibuffer starts out with the default directory.} | |
1516 | (let ((insert-default-directory t)) | |
1517 | (read-file-name "The file is ")) | |
1518 | @end group | |
1519 | ||
1520 | @group | |
1521 | ---------- Buffer: Minibuffer ---------- | |
1522 | The file is ~lewis/manual/@point{} | |
1523 | ---------- Buffer: Minibuffer ---------- | |
1524 | @end group | |
1525 | ||
1526 | @group | |
1527 | ;; @r{Here the minibuffer is empty and only the prompt} | |
1528 | ;; @r{appears on its line.} | |
1529 | (let ((insert-default-directory nil)) | |
1530 | (read-file-name "The file is ")) | |
1531 | @end group | |
1532 | ||
1533 | @group | |
1534 | ---------- Buffer: Minibuffer ---------- | |
1535 | The file is @point{} | |
1536 | ---------- Buffer: Minibuffer ---------- | |
1537 | @end group | |
1538 | @end example | |
1539 | @end defopt | |
1540 | ||
9d2754f5 | 1541 | @defun read-shell-command prompt &optional initial history &rest args |
e4372165 EZ |
1542 | This function reads a shell command from the minibuffer, prompting |
1543 | with @var{prompt} and providing intelligent completion. It completes | |
1544 | the first word of the command using candidates that are appropriate | |
d8f0f8a5 EZ |
1545 | for command names, and the rest of the command words as file names. |
1546 | ||
1547 | This function uses @code{minibuffer-local-shell-command-map} as the | |
9d2754f5 | 1548 | keymap for minibuffer input. The @var{history} argument specifies the |
d8f0f8a5 | 1549 | history list to use; if is omitted or @code{nil}, it defaults to |
e4372165 | 1550 | @code{shell-command-history} (@pxref{Minibuffer History, |
9d2754f5 | 1551 | shell-command-history}). The optional argument @var{initial} |
d8f0f8a5 EZ |
1552 | specifies the initial content of the minibuffer (@pxref{Initial |
1553 | Input}). The rest of @var{args}, if present, are used as the | |
1554 | @var{default} and @var{inherit-input-method} arguments in | |
1555 | @code{read-from-minibuffer} (@pxref{Text from Minibuffer}). | |
e4372165 EZ |
1556 | @end defun |
1557 | ||
1558 | @defvar minibuffer-local-shell-command-map | |
1559 | This keymap is used by @code{read-shell-command} for completing | |
b58b1df8 GM |
1560 | command and file names that are part of a shell command. It uses |
1561 | @code{minibuffer-local-map} as its parent keymap, and binds @key{TAB} | |
1562 | to @code{completion-at-point}. | |
e4372165 EZ |
1563 | @end defvar |
1564 | ||
321cc491 CY |
1565 | @node Completion Variables |
1566 | @subsection Completion Variables | |
dc1ce9aa | 1567 | |
b58b1df8 | 1568 | Here are some variables that can be used to alter the default |
321cc491 | 1569 | completion behavior. |
dc1ce9aa | 1570 | |
321cc491 | 1571 | @cindex completion styles |
dc1ce9aa | 1572 | @defopt completion-styles |
ea0ff314 CY |
1573 | The value of this variable is a list of completion style (symbols) to |
1574 | use for performing completion. A @dfn{completion style} is a set of | |
b58b1df8 | 1575 | rules for generating completions. Each symbol occurring this list |
ea0ff314 | 1576 | must have a corresponding entry in @code{completion-styles-alist}. |
dc1ce9aa CY |
1577 | @end defopt |
1578 | ||
1579 | @defvar completion-styles-alist | |
1580 | This variable stores a list of available completion styles. Each | |
321cc491 CY |
1581 | element in the list has the form |
1582 | ||
1583 | @example | |
ea0ff314 | 1584 | (@var{style} @var{try-completion} @var{all-completions} @var{doc}) |
321cc491 CY |
1585 | @end example |
1586 | ||
1587 | @noindent | |
ea0ff314 CY |
1588 | Here, @var{style} is the name of the completion style (a symbol), |
1589 | which may be used in the @code{completion-styles} variable to refer to | |
1590 | this style; @var{try-completion} is the function that does the | |
1591 | completion; @var{all-completions} is the function that lists the | |
1592 | completions; and @var{doc} is a string describing the completion | |
1593 | style. | |
321cc491 CY |
1594 | |
1595 | The @var{try-completion} and @var{all-completions} functions should | |
1596 | each accept four arguments: @var{string}, @var{collection}, | |
1597 | @var{predicate}, and @var{point}. The @var{string}, @var{collection}, | |
1598 | and @var{predicate} arguments have the same meanings as in | |
1599 | @code{try-completion} (@pxref{Basic Completion}), and the @var{point} | |
1600 | argument is the position of point within @var{string}. Each function | |
1601 | should return a non-@code{nil} value if it performed its job, and | |
1df7defd | 1602 | @code{nil} if it did not (e.g., if there is no way to complete |
321cc491 CY |
1603 | @var{string} according to the completion style). |
1604 | ||
1605 | When the user calls a completion command like | |
dc1ce9aa CY |
1606 | @code{minibuffer-complete} (@pxref{Completion Commands}), Emacs looks |
1607 | for the first style listed in @code{completion-styles} and calls its | |
1608 | @var{try-completion} function. If this function returns @code{nil}, | |
321cc491 CY |
1609 | Emacs moves to the next listed completion style and calls its |
1610 | @var{try-completion} function, and so on until one of the | |
1611 | @var{try-completion} functions successfully performs completion and | |
1612 | returns a non-@code{nil} value. A similar procedure is used for | |
1613 | listing completions, via the @var{all-completions} functions. | |
1614 | ||
1615 | @xref{Completion Styles,,, emacs, The GNU Emacs Manual}, for a | |
1616 | description of the available completion styles. | |
dc1ce9aa CY |
1617 | @end defvar |
1618 | ||
ea0ff314 CY |
1619 | @defopt completion-category-overrides |
1620 | This variable specifies special completion styles and other completion | |
1621 | behaviors to use when completing certain types of text. Its value | |
b58b1df8 GM |
1622 | should be an alist with elements of the form @code{(@var{category} |
1623 | . @var{alist})}. @var{category} is a symbol describing what is being | |
1624 | completed; currently, the @code{buffer}, @code{file}, and | |
1625 | @code{unicode-name} categories are defined, but others can be defined | |
1626 | via specialized completion functions (@pxref{Programmed Completion}). | |
1627 | @var{alist} is an association list describing how completion should | |
1628 | behave for the corresponding category. The following alist keys are | |
1629 | supported: | |
ea0ff314 CY |
1630 | |
1631 | @table @code | |
1632 | @item styles | |
1633 | The value should be a list of completion styles (symbols). | |
1634 | ||
1635 | @item cycle | |
1636 | The value should be a value for @code{completion-cycle-threshold} | |
1637 | (@pxref{Completion Options,,, emacs, The GNU Emacs Manual}) for this | |
1638 | category. | |
1639 | @end table | |
1640 | ||
1641 | @noindent | |
1642 | Additional alist entries may be defined in the future. | |
1643 | @end defopt | |
1644 | ||
321cc491 CY |
1645 | @defvar completion-extra-properties |
1646 | This variable is used to specify extra properties of the current | |
1647 | completion command. It is intended to be let-bound by specialized | |
1648 | completion commands. Its value should be a list of property and value | |
1649 | pairs. The following properties are supported: | |
1650 | ||
1651 | @table @code | |
1652 | @item :annotation-function | |
1653 | The value should be a function to add annotations in the completions | |
1654 | buffer. This function must accept one argument, a completion, and | |
1655 | should either return @code{nil} or a string to be displayed next to | |
1656 | the completion. | |
1657 | ||
1658 | @item :exit-function | |
1659 | The value should be a function to run after performing completion. | |
1660 | The function should accept two arguments, @var{string} and | |
1661 | @var{status}, where @var{string} is the text to which the field was | |
b58b1df8 | 1662 | completed, and @var{status} indicates what kind of operation happened: |
321cc491 CY |
1663 | @code{finished} if text is now complete, @code{sole} if the text |
1664 | cannot be further completed but completion is not finished, or | |
1665 | @code{exact} if the text is a valid completion but may be further | |
1666 | completed. | |
1667 | @end table | |
1668 | @end defvar | |
dc1ce9aa | 1669 | |
b8d4c8d0 GM |
1670 | @node Programmed Completion |
1671 | @subsection Programmed Completion | |
1672 | @cindex programmed completion | |
1673 | ||
fd5a8ae8 SM |
1674 | Sometimes it is not possible or convenient to create an alist or |
1675 | an obarray containing all the intended possible completions ahead | |
1676 | of time. In such a case, you can supply your own function to compute | |
1677 | the completion of a given string. This is called @dfn{programmed | |
1678 | completion}. Emacs uses programmed completion when completing file | |
1679 | names (@pxref{File Name Completion}), among many other cases. | |
b8d4c8d0 | 1680 | |
637821cd SM |
1681 | To use this feature, pass a function as the @var{collection} |
1682 | argument to @code{completing-read}. The function | |
b8d4c8d0 | 1683 | @code{completing-read} arranges to pass your completion function along |
637821cd SM |
1684 | to @code{try-completion}, @code{all-completions}, and other basic |
1685 | completion functions, which will then let your function do all | |
1686 | the work. | |
b8d4c8d0 GM |
1687 | |
1688 | The completion function should accept three arguments: | |
1689 | ||
1690 | @itemize @bullet | |
1691 | @item | |
1692 | The string to be completed. | |
1693 | ||
1694 | @item | |
321cc491 CY |
1695 | A predicate function with which to filter possible matches, or |
1696 | @code{nil} if none. The function should call the predicate for each | |
1697 | possible match, and ignore the match if the predicate returns | |
1698 | @code{nil}. | |
b8d4c8d0 GM |
1699 | |
1700 | @item | |
321cc491 CY |
1701 | A flag specifying the type of completion operation to perform. This |
1702 | is one of the following four values: | |
b8d4c8d0 | 1703 | |
321cc491 CY |
1704 | @table @code |
1705 | @item nil | |
1706 | This specifies a @code{try-completion} operation. The function should | |
1707 | return @code{t} if the specified string is a unique and exact match; | |
1708 | if there is more than one match, it should return the common substring | |
1709 | of all matches (if the string is an exact match for one completion | |
1710 | alternative but also matches other longer alternatives, the return | |
1711 | value is the string); if there are no matches, it should return | |
1712 | @code{nil}. | |
1713 | ||
1714 | @item t | |
1715 | This specifies an @code{all-completions} operation. The function | |
b8d4c8d0 GM |
1716 | should return a list of all possible completions of the specified |
1717 | string. | |
1718 | ||
321cc491 CY |
1719 | @item lambda |
1720 | This specifies a @code{test-completion} operation. The function | |
1721 | should return @code{t} if the specified string is an exact match for | |
1722 | some completion alternative; @code{nil} otherwise. | |
637821cd | 1723 | |
321cc491 CY |
1724 | @item (boundaries . @var{suffix}) |
1725 | This specifies a @code{completion-boundaries} operation. The function | |
9d2754f5 GM |
1726 | should return @code{(boundaries @var{start} . @var{end})}, where |
1727 | @var{start} is the position of the beginning boundary in the specified | |
1728 | string, and @var{end} is the position of the end boundary in | |
1729 | @var{suffix}. | |
ea0ff314 CY |
1730 | |
1731 | @item metadata | |
1732 | This specifies a request for information about the state of the | |
74ca4d39 LL |
1733 | current completion. The return value should have the form |
1734 | @code{(metadata . @var{alist})}, where @var{alist} is an alist whose | |
1735 | elements are described below. | |
321cc491 | 1736 | @end table |
ea0ff314 CY |
1737 | |
1738 | @noindent | |
1739 | If the flag has any other value, the completion function should return | |
1740 | @code{nil}. | |
b8d4c8d0 GM |
1741 | @end itemize |
1742 | ||
ea0ff314 CY |
1743 | The following is a list of metadata entries that a completion function |
1744 | may return in response to a @code{metadata} flag argument: | |
1745 | ||
1746 | @table @code | |
1747 | @item category | |
1748 | The value should be a symbol describing what kind of text the | |
1749 | completion function is trying to complete. If the symbol matches one | |
1750 | of the keys in @code{completion-category-overrides}, the usual | |
1751 | completion behavior is overridden. @xref{Completion Variables}. | |
1752 | ||
1753 | @item annotation-function | |
1754 | The value should be a function for @dfn{annotating} completions. The | |
1755 | function should take one argument, @var{string}, which is a possible | |
1756 | completion. It should return a string, which is displayed after the | |
2bb0eca1 | 1757 | completion @var{string} in the @file{*Completions*} buffer. |
ea0ff314 CY |
1758 | |
1759 | @item display-sort-function | |
1760 | The value should be a function for sorting completions. The function | |
1761 | should take one argument, a list of completion strings, and return a | |
1762 | sorted list of completion strings. It is allowed to alter the input | |
1763 | list destructively. | |
1764 | ||
1765 | @item cycle-sort-function | |
1766 | The value should be a function for sorting completions, when | |
1767 | @code{completion-cycle-threshold} is non-@code{nil} and the user is | |
1768 | cycling through completion alternatives. @xref{Completion Options,,, | |
1769 | emacs, The GNU Emacs Manual}. Its argument list and return value are | |
1770 | the same as for @code{display-sort-function}. | |
1771 | @end table | |
1772 | ||
25c0d999 SM |
1773 | @defun completion-table-dynamic function |
1774 | This function is a convenient way to write a function that can act as | |
b58b1df8 | 1775 | a programmed completion function. The argument @var{function} should be |
b8d4c8d0 GM |
1776 | a function that takes one argument, a string, and returns an alist of |
1777 | possible completions of it. You can think of | |
25c0d999 | 1778 | @code{completion-table-dynamic} as a transducer between that interface |
b8d4c8d0 | 1779 | and the interface for programmed completion functions. |
25c0d999 | 1780 | @end defun |
b8d4c8d0 | 1781 | |
60236b0d CY |
1782 | @node Completion in Buffers |
1783 | @subsection Completion in Ordinary Buffers | |
1784 | @cindex inline completion | |
1785 | ||
1786 | @findex completion-at-point | |
1787 | Although completion is usually done in the minibuffer, the | |
1788 | completion facility can also be used on the text in ordinary Emacs | |
1789 | buffers. In many major modes, in-buffer completion is performed by | |
1790 | the @kbd{C-M-i} or @kbd{M-@key{TAB}} command, bound to | |
1791 | @code{completion-at-point}. @xref{Symbol Completion,,, emacs, The GNU | |
1792 | Emacs Manual}. This command uses the abnormal hook variable | |
1793 | @code{completion-at-point-functions}: | |
1794 | ||
1795 | @defvar completion-at-point-functions | |
1796 | The value of this abnormal hook should be a list of functions, which | |
1797 | are used to compute a completion table for completing the text at | |
1798 | point. It can be used by major modes to provide mode-specific | |
1799 | completion tables (@pxref{Major Mode Conventions}). | |
1800 | ||
1801 | When the command @code{completion-at-point} runs, it calls the | |
1802 | functions in the list one by one, without any argument. Each function | |
1803 | should return @code{nil} if it is unable to produce a completion table | |
1804 | for the text at point. Otherwise it should return a list of the form | |
1805 | ||
1806 | @example | |
1807 | (@var{start} @var{end} @var{collection} . @var{props}) | |
1808 | @end example | |
1809 | ||
1810 | @noindent | |
1811 | @var{start} and @var{end} delimit the text to complete (which should | |
1812 | enclose point). @var{collection} is a completion table for completing | |
1813 | that text, in a form suitable for passing as the second argument to | |
1814 | @code{try-completion} (@pxref{Basic Completion}); completion | |
1815 | alternatives will be generated from this completion table in the usual | |
1816 | way, via the completion styles defined in @code{completion-styles} | |
321cc491 | 1817 | (@pxref{Completion Variables}). @var{props} is a property list for |
245d176b CY |
1818 | additional information; any of the properties in |
1819 | @code{completion-extra-properties} are recognized (@pxref{Completion | |
1820 | Variables}), as well as the following additional ones: | |
60236b0d CY |
1821 | |
1822 | @table @code | |
1823 | @item :predicate | |
1824 | The value should be a predicate that completion candidates need to | |
1825 | satisfy. | |
1826 | ||
1827 | @item :exclusive | |
1828 | If the value is @code{no}, then if the completion table fails to match | |
b58b1df8 | 1829 | the text at point, @code{completion-at-point} moves on to the |
60236b0d CY |
1830 | next function in @code{completion-at-point-functions} instead of |
1831 | reporting a completion failure. | |
1832 | @end table | |
1833 | ||
1834 | A function in @code{completion-at-point-functions} may also return a | |
1835 | function. In that case, that returned function is called, with no | |
1836 | argument, and it is entirely responsible for performing the | |
1837 | completion. We discourage this usage; it is intended to help convert | |
1838 | old code to using @code{completion-at-point}. | |
1839 | ||
1840 | The first function in @code{completion-at-point-functions} to return a | |
1841 | non-@code{nil} value is used by @code{completion-at-point}. The | |
1842 | remaining functions are not called. The exception to this is when | |
b58b1df8 | 1843 | there is an @code{:exclusive} specification, as described above. |
60236b0d CY |
1844 | @end defvar |
1845 | ||
1846 | The following function provides a convenient way to perform | |
1847 | completion on an arbitrary stretch of text in an Emacs buffer: | |
1848 | ||
1849 | @defun completion-in-region start end collection &optional predicate | |
1850 | This function completes the text in the current buffer between the | |
1851 | positions @var{start} and @var{end}, using @var{collection}. The | |
1852 | argument @var{collection} has the same meaning as in | |
1853 | @code{try-completion} (@pxref{Basic Completion}). | |
1854 | ||
1855 | This function inserts the completion text directly into the current | |
1856 | buffer. Unlike @code{completing-read} (@pxref{Minibuffer | |
1857 | Completion}), it does not activate the minibuffer. | |
1858 | ||
1859 | For this function to work, point must be somewhere between @var{start} | |
1860 | and @var{end}. | |
1861 | @end defun | |
1862 | ||
1863 | ||
b8d4c8d0 GM |
1864 | @node Yes-or-No Queries |
1865 | @section Yes-or-No Queries | |
1866 | @cindex asking the user questions | |
1867 | @cindex querying the user | |
1868 | @cindex yes-or-no questions | |
1869 | ||
1870 | This section describes functions used to ask the user a yes-or-no | |
1871 | question. The function @code{y-or-n-p} can be answered with a single | |
1872 | character; it is useful for questions where an inadvertent wrong answer | |
1873 | will not have serious consequences. @code{yes-or-no-p} is suitable for | |
1874 | more momentous questions, since it requires three or four characters to | |
1875 | answer. | |
1876 | ||
1877 | If either of these functions is called in a command that was invoked | |
1878 | using the mouse---more precisely, if @code{last-nonmenu-event} | |
1879 | (@pxref{Command Loop Info}) is either @code{nil} or a list---then it | |
1880 | uses a dialog box or pop-up menu to ask the question. Otherwise, it | |
c0ea08d2 | 1881 | uses keyboard input. You can force use either of the mouse or of keyboard |
b8d4c8d0 GM |
1882 | input by binding @code{last-nonmenu-event} to a suitable value around |
1883 | the call. | |
1884 | ||
1885 | Strictly speaking, @code{yes-or-no-p} uses the minibuffer and | |
1886 | @code{y-or-n-p} does not; but it seems best to describe them together. | |
1887 | ||
1888 | @defun y-or-n-p prompt | |
1889 | This function asks the user a question, expecting input in the echo | |
1890 | area. It returns @code{t} if the user types @kbd{y}, @code{nil} if the | |
1891 | user types @kbd{n}. This function also accepts @key{SPC} to mean yes | |
9d2754f5 | 1892 | and @key{DEL} to mean no. It accepts @kbd{C-]} to mean ``quit'', like |
b8d4c8d0 GM |
1893 | @kbd{C-g}, because the question might look like a minibuffer and for |
1894 | that reason the user might try to use @kbd{C-]} to get out. The answer | |
1895 | is a single character, with no @key{RET} needed to terminate it. Upper | |
1896 | and lower case are equivalent. | |
1897 | ||
1898 | ``Asking the question'' means printing @var{prompt} in the echo area, | |
1899 | followed by the string @w{@samp{(y or n) }}. If the input is not one of | |
1900 | the expected answers (@kbd{y}, @kbd{n}, @kbd{@key{SPC}}, | |
1901 | @kbd{@key{DEL}}, or something that quits), the function responds | |
1902 | @samp{Please answer y or n.}, and repeats the request. | |
1903 | ||
1904 | This function does not actually use the minibuffer, since it does not | |
1905 | allow editing of the answer. It actually uses the echo area (@pxref{The | |
1906 | Echo Area}), which uses the same screen space as the minibuffer. The | |
1907 | cursor moves to the echo area while the question is being asked. | |
1908 | ||
1909 | The answers and their meanings, even @samp{y} and @samp{n}, are not | |
011474aa CY |
1910 | hardwired, and are specified by the keymap @code{query-replace-map} |
1911 | (@pxref{Search and Replace}). In particular, if the user enters the | |
1912 | special responses @code{recenter}, @code{scroll-up}, | |
1913 | @code{scroll-down}, @code{scroll-other-window}, or | |
1914 | @code{scroll-other-window-down} (respectively bound to @kbd{C-l}, | |
1915 | @kbd{C-v}, @kbd{M-v}, @kbd{C-M-v} and @kbd{C-M-S-v} in | |
1916 | @code{query-replace-map}), this function performs the specified window | |
1917 | recentering or scrolling operation, and poses the question again. | |
b8d4c8d0 GM |
1918 | |
1919 | @noindent | |
1920 | We show successive lines of echo area messages, but only one actually | |
1921 | appears on the screen at a time. | |
1922 | @end defun | |
1923 | ||
9d2754f5 | 1924 | @defun y-or-n-p-with-timeout prompt seconds default |
b8d4c8d0 GM |
1925 | Like @code{y-or-n-p}, except that if the user fails to answer within |
1926 | @var{seconds} seconds, this function stops waiting and returns | |
9d2754f5 | 1927 | @var{default}. It works by setting up a timer; see @ref{Timers}. |
b8d4c8d0 GM |
1928 | The argument @var{seconds} may be an integer or a floating point number. |
1929 | @end defun | |
1930 | ||
1931 | @defun yes-or-no-p prompt | |
1932 | This function asks the user a question, expecting input in the | |
1933 | minibuffer. It returns @code{t} if the user enters @samp{yes}, | |
1934 | @code{nil} if the user types @samp{no}. The user must type @key{RET} to | |
1935 | finalize the response. Upper and lower case are equivalent. | |
1936 | ||
1937 | @code{yes-or-no-p} starts by displaying @var{prompt} in the echo area, | |
1938 | followed by @w{@samp{(yes or no) }}. The user must type one of the | |
1939 | expected responses; otherwise, the function responds @samp{Please answer | |
1940 | yes or no.}, waits about two seconds and repeats the request. | |
1941 | ||
1942 | @code{yes-or-no-p} requires more work from the user than | |
1943 | @code{y-or-n-p} and is appropriate for more crucial decisions. | |
1944 | ||
1945 | Here is an example: | |
1946 | ||
1947 | @smallexample | |
1948 | @group | |
1949 | (yes-or-no-p "Do you really want to remove everything? ") | |
1950 | ||
1951 | ;; @r{After evaluation of the preceding expression,} | |
1952 | ;; @r{the following prompt appears,} | |
1953 | ;; @r{with an empty minibuffer:} | |
1954 | @end group | |
1955 | ||
1956 | @group | |
1957 | ---------- Buffer: minibuffer ---------- | |
1958 | Do you really want to remove everything? (yes or no) | |
1959 | ---------- Buffer: minibuffer ---------- | |
1960 | @end group | |
1961 | @end smallexample | |
1962 | ||
1963 | @noindent | |
1964 | If the user first types @kbd{y @key{RET}}, which is invalid because this | |
1965 | function demands the entire word @samp{yes}, it responds by displaying | |
1966 | these prompts, with a brief pause between them: | |
1967 | ||
1968 | @smallexample | |
1969 | @group | |
1970 | ---------- Buffer: minibuffer ---------- | |
1971 | Please answer yes or no. | |
1972 | Do you really want to remove everything? (yes or no) | |
1973 | ---------- Buffer: minibuffer ---------- | |
1974 | @end group | |
1975 | @end smallexample | |
1976 | @end defun | |
1977 | ||
1978 | @node Multiple Queries | |
1979 | @section Asking Multiple Y-or-N Questions | |
1980 | ||
1981 | When you have a series of similar questions to ask, such as ``Do you | |
1982 | want to save this buffer'' for each buffer in turn, you should use | |
1983 | @code{map-y-or-n-p} to ask the collection of questions, rather than | |
1984 | asking each question individually. This gives the user certain | |
1985 | convenient facilities such as the ability to answer the whole series at | |
1986 | once. | |
1987 | ||
1988 | @defun map-y-or-n-p prompter actor list &optional help action-alist no-cursor-in-echo-area | |
1989 | This function asks the user a series of questions, reading a | |
1990 | single-character answer in the echo area for each one. | |
1991 | ||
1992 | The value of @var{list} specifies the objects to ask questions about. | |
1993 | It should be either a list of objects or a generator function. If it is | |
1994 | a function, it should expect no arguments, and should return either the | |
c0ea08d2 | 1995 | next object to ask about, or @code{nil}, meaning to stop asking questions. |
b8d4c8d0 GM |
1996 | |
1997 | The argument @var{prompter} specifies how to ask each question. If | |
1998 | @var{prompter} is a string, the question text is computed like this: | |
1999 | ||
2000 | @example | |
2001 | (format @var{prompter} @var{object}) | |
2002 | @end example | |
2003 | ||
2004 | @noindent | |
2005 | where @var{object} is the next object to ask about (as obtained from | |
2006 | @var{list}). | |
2007 | ||
2008 | If not a string, @var{prompter} should be a function of one argument | |
2009 | (the next object to ask about) and should return the question text. If | |
2010 | the value is a string, that is the question to ask the user. The | |
c0ea08d2 GM |
2011 | function can also return @code{t}, meaning do act on this object (and |
2012 | don't ask the user), or @code{nil}, meaning ignore this object (and don't | |
b8d4c8d0 GM |
2013 | ask the user). |
2014 | ||
2015 | The argument @var{actor} says how to act on the answers that the user | |
2016 | gives. It should be a function of one argument, and it is called with | |
2017 | each object that the user says yes for. Its argument is always an | |
2018 | object obtained from @var{list}. | |
2019 | ||
2020 | If the argument @var{help} is given, it should be a list of this form: | |
2021 | ||
2022 | @example | |
2023 | (@var{singular} @var{plural} @var{action}) | |
2024 | @end example | |
2025 | ||
2026 | @noindent | |
2027 | where @var{singular} is a string containing a singular noun that | |
2028 | describes the objects conceptually being acted on, @var{plural} is the | |
2029 | corresponding plural noun, and @var{action} is a transitive verb | |
2030 | describing what @var{actor} does. | |
2031 | ||
2032 | If you don't specify @var{help}, the default is @code{("object" | |
2033 | "objects" "act on")}. | |
2034 | ||
2035 | Each time a question is asked, the user may enter @kbd{y}, @kbd{Y}, or | |
2036 | @key{SPC} to act on that object; @kbd{n}, @kbd{N}, or @key{DEL} to skip | |
2037 | that object; @kbd{!} to act on all following objects; @key{ESC} or | |
2038 | @kbd{q} to exit (skip all following objects); @kbd{.} (period) to act on | |
2039 | the current object and then exit; or @kbd{C-h} to get help. These are | |
2040 | the same answers that @code{query-replace} accepts. The keymap | |
2041 | @code{query-replace-map} defines their meaning for @code{map-y-or-n-p} | |
2042 | as well as for @code{query-replace}; see @ref{Search and Replace}. | |
2043 | ||
2044 | You can use @var{action-alist} to specify additional possible answers | |
2045 | and what they mean. It is an alist of elements of the form | |
2046 | @code{(@var{char} @var{function} @var{help})}, each of which defines one | |
2047 | additional answer. In this element, @var{char} is a character (the | |
2048 | answer); @var{function} is a function of one argument (an object from | |
2049 | @var{list}); @var{help} is a string. | |
2050 | ||
2051 | When the user responds with @var{char}, @code{map-y-or-n-p} calls | |
2052 | @var{function}. If it returns non-@code{nil}, the object is considered | |
9d2754f5 | 2053 | ``acted upon'', and @code{map-y-or-n-p} advances to the next object in |
b8d4c8d0 GM |
2054 | @var{list}. If it returns @code{nil}, the prompt is repeated for the |
2055 | same object. | |
2056 | ||
2057 | Normally, @code{map-y-or-n-p} binds @code{cursor-in-echo-area} while | |
2058 | prompting. But if @var{no-cursor-in-echo-area} is non-@code{nil}, it | |
2059 | does not do that. | |
2060 | ||
2061 | If @code{map-y-or-n-p} is called in a command that was invoked using the | |
2062 | mouse---more precisely, if @code{last-nonmenu-event} (@pxref{Command | |
2063 | Loop Info}) is either @code{nil} or a list---then it uses a dialog box | |
2064 | or pop-up menu to ask the question. In this case, it does not use | |
c0ea08d2 | 2065 | keyboard input or the echo area. You can force use either of the mouse or |
b8d4c8d0 GM |
2066 | of keyboard input by binding @code{last-nonmenu-event} to a suitable |
2067 | value around the call. | |
2068 | ||
2069 | The return value of @code{map-y-or-n-p} is the number of objects acted on. | |
2070 | @end defun | |
c0ea08d2 GM |
2071 | @c FIXME An example of this would be more useful than all the |
2072 | @c preceding examples of simple things. | |
b8d4c8d0 GM |
2073 | |
2074 | @node Reading a Password | |
2075 | @section Reading a Password | |
2076 | @cindex passwords, reading | |
2077 | ||
2078 | To read a password to pass to another program, you can use the | |
2079 | function @code{read-passwd}. | |
2080 | ||
2081 | @defun read-passwd prompt &optional confirm default | |
2082 | This function reads a password, prompting with @var{prompt}. It does | |
2083 | not echo the password as the user types it; instead, it echoes @samp{.} | |
2084 | for each character in the password. | |
2085 | ||
2086 | The optional argument @var{confirm}, if non-@code{nil}, says to read the | |
2087 | password twice and insist it must be the same both times. If it isn't | |
2088 | the same, the user has to type it over and over until the last two | |
2089 | times match. | |
2090 | ||
2091 | The optional argument @var{default} specifies the default password to | |
2092 | return if the user enters empty input. If @var{default} is @code{nil}, | |
2093 | then @code{read-passwd} returns the null string in that case. | |
2094 | @end defun | |
2095 | ||
2096 | @node Minibuffer Commands | |
2097 | @section Minibuffer Commands | |
2098 | ||
2099 | This section describes some commands meant for use in the | |
2100 | minibuffer. | |
2101 | ||
2102 | @deffn Command exit-minibuffer | |
2103 | This command exits the active minibuffer. It is normally bound to | |
2104 | keys in minibuffer local keymaps. | |
2105 | @end deffn | |
2106 | ||
2107 | @deffn Command self-insert-and-exit | |
2108 | This command exits the active minibuffer after inserting the last | |
21e96f8f | 2109 | character typed on the keyboard (found in @code{last-command-event}; |
b8d4c8d0 GM |
2110 | @pxref{Command Loop Info}). |
2111 | @end deffn | |
2112 | ||
2113 | @deffn Command previous-history-element n | |
2114 | This command replaces the minibuffer contents with the value of the | |
2115 | @var{n}th previous (older) history element. | |
2116 | @end deffn | |
2117 | ||
2118 | @deffn Command next-history-element n | |
2119 | This command replaces the minibuffer contents with the value of the | |
2120 | @var{n}th more recent history element. | |
2121 | @end deffn | |
2122 | ||
2123 | @deffn Command previous-matching-history-element pattern n | |
2124 | This command replaces the minibuffer contents with the value of the | |
2125 | @var{n}th previous (older) history element that matches @var{pattern} (a | |
2126 | regular expression). | |
2127 | @end deffn | |
2128 | ||
2129 | @deffn Command next-matching-history-element pattern n | |
2130 | This command replaces the minibuffer contents with the value of the | |
2131 | @var{n}th next (newer) history element that matches @var{pattern} (a | |
2132 | regular expression). | |
2133 | @end deffn | |
2134 | ||
c0ea08d2 GM |
2135 | @deffn Command previous-complete-history-element n |
2136 | This command replaces the minibuffer contents with the value of the | |
2137 | @var{n}th previous (older) history element that completes the current | |
2138 | contents of the minibuffer before the point. | |
2139 | @end deffn | |
2140 | ||
2141 | @deffn Command next-complete-history-element n | |
2142 | This command replaces the minibuffer contents with the value of the | |
2143 | @var{n}th next (newer) history element that completes the current | |
2144 | contents of the minibuffer before the point. | |
2145 | @end deffn | |
2146 | ||
2147 | ||
b8d4c8d0 GM |
2148 | @node Minibuffer Windows |
2149 | @section Minibuffer Windows | |
2150 | @cindex minibuffer windows | |
2151 | ||
2152 | These functions access and select minibuffer windows | |
2153 | and test whether they are active. | |
2154 | ||
2155 | @defun active-minibuffer-window | |
2156 | This function returns the currently active minibuffer window, or | |
c0ea08d2 | 2157 | @code{nil} if there is none. |
b8d4c8d0 GM |
2158 | @end defun |
2159 | ||
2160 | @defun minibuffer-window &optional frame | |
2161 | @anchor{Definition of minibuffer-window} | |
2162 | This function returns the minibuffer window used for frame @var{frame}. | |
2163 | If @var{frame} is @code{nil}, that stands for the current frame. Note | |
2164 | that the minibuffer window used by a frame need not be part of that | |
2165 | frame---a frame that has no minibuffer of its own necessarily uses some | |
2166 | other frame's minibuffer window. | |
2167 | @end defun | |
2168 | ||
2169 | @defun set-minibuffer-window window | |
2170 | This function specifies @var{window} as the minibuffer window to use. | |
2171 | This affects where the minibuffer is displayed if you put text in it | |
2172 | without invoking the usual minibuffer commands. It has no effect on | |
2173 | the usual minibuffer input functions because they all start by | |
2174 | choosing the minibuffer window according to the current frame. | |
2175 | @end defun | |
2176 | ||
2177 | @c Emacs 19 feature | |
2178 | @defun window-minibuffer-p &optional window | |
2179 | This function returns non-@code{nil} if @var{window} is a minibuffer | |
2180 | window. | |
2181 | @var{window} defaults to the selected window. | |
2182 | @end defun | |
2183 | ||
2184 | It is not correct to determine whether a given window is a minibuffer by | |
2185 | comparing it with the result of @code{(minibuffer-window)}, because | |
2186 | there can be more than one minibuffer window if there is more than one | |
2187 | frame. | |
2188 | ||
2189 | @defun minibuffer-window-active-p window | |
c0ea08d2 GM |
2190 | This function returns non-@code{nil} if @var{window} is the currently |
2191 | active minibuffer window. | |
b8d4c8d0 GM |
2192 | @end defun |
2193 | ||
2194 | @node Minibuffer Contents | |
2195 | @section Minibuffer Contents | |
2196 | ||
2197 | These functions access the minibuffer prompt and contents. | |
2198 | ||
2199 | @defun minibuffer-prompt | |
2200 | This function returns the prompt string of the currently active | |
2201 | minibuffer. If no minibuffer is active, it returns @code{nil}. | |
2202 | @end defun | |
2203 | ||
2204 | @defun minibuffer-prompt-end | |
2205 | This function returns the current | |
2206 | position of the end of the minibuffer prompt, if a minibuffer is | |
2207 | current. Otherwise, it returns the minimum valid buffer position. | |
2208 | @end defun | |
2209 | ||
2210 | @defun minibuffer-prompt-width | |
2211 | This function returns the current display-width of the minibuffer | |
2212 | prompt, if a minibuffer is current. Otherwise, it returns zero. | |
2213 | @end defun | |
2214 | ||
2215 | @defun minibuffer-contents | |
2216 | This function returns the editable | |
2217 | contents of the minibuffer (that is, everything except the prompt) as | |
2218 | a string, if a minibuffer is current. Otherwise, it returns the | |
2219 | entire contents of the current buffer. | |
2220 | @end defun | |
2221 | ||
2222 | @defun minibuffer-contents-no-properties | |
2223 | This is like @code{minibuffer-contents}, except that it does not copy text | |
2224 | properties, just the characters themselves. @xref{Text Properties}. | |
2225 | @end defun | |
2226 | ||
b8d4c8d0 GM |
2227 | @defun delete-minibuffer-contents |
2228 | This function erases the editable contents of the minibuffer (that is, | |
2229 | everything except the prompt), if a minibuffer is current. Otherwise, | |
2230 | it erases the entire current buffer. | |
2231 | @end defun | |
2232 | ||
2233 | @node Recursive Mini | |
2234 | @section Recursive Minibuffers | |
2235 | @cindex recursive minibuffers | |
2236 | ||
2237 | These functions and variables deal with recursive minibuffers | |
2238 | (@pxref{Recursive Editing}): | |
2239 | ||
2240 | @defun minibuffer-depth | |
2241 | This function returns the current depth of activations of the | |
2242 | minibuffer, a nonnegative integer. If no minibuffers are active, it | |
2243 | returns zero. | |
2244 | @end defun | |
2245 | ||
2246 | @defopt enable-recursive-minibuffers | |
2247 | If this variable is non-@code{nil}, you can invoke commands (such as | |
2248 | @code{find-file}) that use minibuffers even while the minibuffer window | |
2249 | is active. Such invocation produces a recursive editing level for a new | |
2250 | minibuffer. The outer-level minibuffer is invisible while you are | |
2251 | editing the inner one. | |
2252 | ||
2253 | If this variable is @code{nil}, you cannot invoke minibuffer | |
2254 | commands when the minibuffer window is active, not even if you switch to | |
2255 | another window to do it. | |
2256 | @end defopt | |
2257 | ||
2258 | @c Emacs 19 feature | |
2259 | If a command name has a property @code{enable-recursive-minibuffers} | |
2260 | that is non-@code{nil}, then the command can use the minibuffer to read | |
2261 | arguments even if it is invoked from the minibuffer. A command can | |
2262 | also achieve this by binding @code{enable-recursive-minibuffers} | |
2263 | to @code{t} in the interactive declaration (@pxref{Using Interactive}). | |
2264 | The minibuffer command @code{next-matching-history-element} (normally | |
2265 | @kbd{M-s} in the minibuffer) does the latter. | |
2266 | ||
2267 | @node Minibuffer Misc | |
2268 | @section Minibuffer Miscellany | |
2269 | ||
2270 | @defun minibufferp &optional buffer-or-name | |
2271 | This function returns non-@code{nil} if @var{buffer-or-name} is a | |
2272 | minibuffer. If @var{buffer-or-name} is omitted, it tests the current | |
2273 | buffer. | |
2274 | @end defun | |
2275 | ||
2276 | @defvar minibuffer-setup-hook | |
2277 | This is a normal hook that is run whenever the minibuffer is entered. | |
2278 | @xref{Hooks}. | |
2279 | @end defvar | |
2280 | ||
2281 | @defvar minibuffer-exit-hook | |
2282 | This is a normal hook that is run whenever the minibuffer is exited. | |
2283 | @xref{Hooks}. | |
2284 | @end defvar | |
2285 | ||
2286 | @defvar minibuffer-help-form | |
2287 | @anchor{Definition of minibuffer-help-form} | |
2288 | The current value of this variable is used to rebind @code{help-form} | |
2289 | locally inside the minibuffer (@pxref{Help Functions}). | |
2290 | @end defvar | |
2291 | ||
2292 | @defvar minibuffer-scroll-window | |
2293 | @anchor{Definition of minibuffer-scroll-window} | |
2294 | If the value of this variable is non-@code{nil}, it should be a window | |
2295 | object. When the function @code{scroll-other-window} is called in the | |
2296 | minibuffer, it scrolls this window. | |
2297 | @end defvar | |
2298 | ||
2299 | @defun minibuffer-selected-window | |
c0ea08d2 | 2300 | This function returns the window that was selected when the |
b8d4c8d0 GM |
2301 | minibuffer was entered. If selected window is not a minibuffer |
2302 | window, it returns @code{nil}. | |
2303 | @end defun | |
2304 | ||
2305 | @defopt max-mini-window-height | |
2306 | This variable specifies the maximum height for resizing minibuffer | |
2307 | windows. If a float, it specifies a fraction of the height of the | |
2308 | frame. If an integer, it specifies a number of lines. | |
2309 | @end defopt | |
2310 | ||
c0ea08d2 | 2311 | @vindex minibuffer-message-timeout |
106e6894 | 2312 | @defun minibuffer-message string &rest args |
b8d4c8d0 | 2313 | This function displays @var{string} temporarily at the end of the |
c0ea08d2 GM |
2314 | minibuffer text, for a few seconds, or until the next input event |
2315 | arrives, whichever comes first. The variable | |
2316 | @code{minibuffer-message-timeout} specifies the number of seconds to | |
2317 | wait in the absence of input. It defaults to 2. If @var{args} is | |
2318 | non-@code{nil}, the actual message is obtained by passing @var{string} | |
2319 | and @var{args} through @code{format}. @xref{Formatting Strings}. | |
b8d4c8d0 | 2320 | @end defun |
c0ea08d2 GM |
2321 | |
2322 | @deffn Command minibuffer-inactive-mode | |
2323 | This is the major mode used in inactive minibuffers. It uses | |
2324 | keymap @code{minibuffer-inactive-mode-map}. This can be useful | |
2325 | if the minibuffer is in a separate frame. @xref{Minibuffers and Frames}. | |
2326 | @end deffn |