2 @c This is part of the GNU Emacs Lisp Reference Manual.
3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998 Free Software Foundation, Inc.
4 @c See the file elisp.texi for copying conditions.
5 @setfilename ../info/minibuf
6 @node Minibuffers, Command Loop, Read and Print, Top
8 @cindex arguments, reading
9 @cindex complex arguments
12 A @dfn{minibuffer} is a special buffer that Emacs commands use to read
13 arguments more complicated than the single numeric prefix argument.
14 These arguments include file names, buffer names, and command names (as
15 in @kbd{M-x}). The minibuffer is displayed on the bottom line of the
16 frame, in the same place as the echo area, but only while it is in use
17 for reading an argument.
20 * Intro to Minibuffers:: Basic information about minibuffers.
21 * Text from Minibuffer:: How to read a straight text string.
22 * Object from Minibuffer:: How to read a Lisp object or expression.
23 * Minibuffer History:: Recording previous minibuffer inputs
24 so the user can reuse them.
25 * Completion:: How to invoke and customize completion.
26 * Yes-or-No Queries:: Asking a question with a simple answer.
27 * Multiple Queries:: Asking a series of similar questions.
28 * Reading a Password:: Reading a password from the terminal.
29 * Minibuffer Misc:: Various customization hooks and variables.
32 @node Intro to Minibuffers
33 @section Introduction to Minibuffers
35 In most ways, a minibuffer is a normal Emacs buffer. Most operations
36 @emph{within} a buffer, such as editing commands, work normally in a
37 minibuffer. However, many operations for managing buffers do not apply
38 to minibuffers. The name of a minibuffer always has the form @w{@samp{
39 *Minibuf-@var{number}}}, and it cannot be changed. Minibuffers are
40 displayed only in special windows used only for minibuffers; these
41 windows always appear at the bottom of a frame. (Sometimes frames have
42 no minibuffer window, and sometimes a special kind of frame contains
43 nothing but a minibuffer window; see @ref{Minibuffers and Frames}.)
45 The text in the minibuffer always starts with the @dfn{prompt string},
46 the text that was specified by the program that is using the minibuffer
47 to tell the user what sort of input to type. This text is marked
48 read-only so you won't accidentally delete or change it. It is also
49 marked as a field (@pxref{Fields}), so that certain motion functions,
50 including @code{beginning-of-line}, @code{forward-word},
51 @code{forward-sentence}, and @code{forward-paragraph}, stop at the
52 boundary between the prompt and the actual text. (In older Emacs
53 versions, the prompt was displayed using a special mechanism and was not
54 part of the buffer contents.)
56 The minibuffer's window is normally a single line; it grows
57 automatically if necessary if the contents require more space. You can
58 explicitly resize it temporarily with the window sizing commands; it
59 reverts to its normal size when the minibuffer is exited. You can
60 resize it permanently by using the window sizing commands in the frame's
61 other window, when the minibuffer is not active. If the frame contains
62 just a minibuffer, you can change the minibuffer's size by changing the
65 If a command uses a minibuffer while there is an active minibuffer,
66 this is called a @dfn{recursive minibuffer}. The first minibuffer is
67 named @w{@samp{ *Minibuf-0*}}. Recursive minibuffers are named by
68 incrementing the number at the end of the name. (The names begin with a
69 space so that they won't show up in normal buffer lists.) Of several
70 recursive minibuffers, the innermost (or most recently entered) is the
71 active minibuffer. We usually call this ``the'' minibuffer. You can
72 permit or forbid recursive minibuffers by setting the variable
73 @code{enable-recursive-minibuffers} or by putting properties of that
74 name on command symbols (@pxref{Minibuffer Misc}).
76 Like other buffers, a minibuffer may use any of several local keymaps
77 (@pxref{Keymaps}); these contain various exit commands and in some cases
78 completion commands (@pxref{Completion}).
82 @code{minibuffer-local-map} is for ordinary input (no completion).
85 @code{minibuffer-local-ns-map} is similar, except that @key{SPC} exits
86 just like @key{RET}. This is used mainly for Mocklisp compatibility.
89 @code{minibuffer-local-completion-map} is for permissive completion.
92 @code{minibuffer-local-must-match-map} is for strict completion and
93 for cautious completion.
96 When Emacs is running in batch mode, any request to read from the
97 minibuffer actually reads a line from the standard input descriptor that
98 was supplied when Emacs was started.
100 @node Text from Minibuffer
101 @section Reading Text Strings with the Minibuffer
103 Most often, the minibuffer is used to read text as a string. It can
104 also be used to read a Lisp object in textual form. The most basic
105 primitive for minibuffer input is @code{read-from-minibuffer}; it can do
108 In most cases, you should not call minibuffer input functions in the
109 middle of a Lisp function. Instead, do all minibuffer input as part of
110 reading the arguments for a command, in the @code{interactive}
111 specification. @xref{Defining Commands}.
113 @defun read-from-minibuffer prompt-string &optional initial-contents keymap read hist default inherit-input-method
114 This function is the most general way to get input through the
115 minibuffer. By default, it accepts arbitrary text and returns it as a
116 string; however, if @var{read} is non-@code{nil}, then it uses
117 @code{read} to convert the text into a Lisp object (@pxref{Input
120 The first thing this function does is to activate a minibuffer and
121 display it with @var{prompt-string} as the prompt. This value must be a
122 string. Then the user can edit text in the minibuffer.
124 When the user types a command to exit the minibuffer,
125 @code{read-from-minibuffer} constructs the return value from the text in
126 the minibuffer. Normally it returns a string containing that text.
127 However, if @var{read} is non-@code{nil}, @code{read-from-minibuffer}
128 reads the text and returns the resulting Lisp object, unevaluated.
129 (@xref{Input Functions}, for information about reading.)
131 The argument @var{default} specifies a default value to make available
132 through the history commands. It should be a string, or @code{nil}. If
133 @var{read} is non-@code{nil}, then @var{default} is also used as the
134 input to @code{read}, if the user enters empty input. However, in the
135 usual case (where @var{read} is @code{nil}), @code{read-from-minibuffer}
136 does not return @var{default} when the user enters empty input; it
137 returns an empty string, @code{""}. In this respect, it is different
138 from all the other minibuffer input functions in this chapter.
140 If @var{keymap} is non-@code{nil}, that keymap is the local keymap to
141 use in the minibuffer. If @var{keymap} is omitted or @code{nil}, the
142 value of @code{minibuffer-local-map} is used as the keymap. Specifying
143 a keymap is the most important way to customize the minibuffer for
144 various applications such as completion.
146 The argument @var{hist} specifies which history list variable to use
147 for saving the input and for history commands used in the minibuffer.
148 It defaults to @code{minibuffer-history}. @xref{Minibuffer History}.
150 If the variable @code{minibuffer-allow-text-properties} is
151 non-@code{nil}, then the string which is returned includes whatever text
152 properties were present in the minibuffer. Otherwise all the text
153 properties are stripped when the value is returned.
155 If the argument @var{inherit-input-method} is non-@code{nil}, then the
156 minibuffer inherits the current input method (@pxref{Input Methods}) and
157 the setting of @code{enable-multibyte-characters} (@pxref{Text
158 Representations}) from whichever buffer was current before entering the
161 If @var{initial-contents} is a string, @code{read-from-minibuffer}
162 inserts it into the minibuffer, leaving point at the end, before the
163 user starts to edit the text. The minibuffer appears with this text as
164 its initial contents.
166 Alternatively, @var{initial-contents} can be a cons cell of the form
167 @code{(@var{string} . @var{position})}. This means to insert
168 @var{string} in the minibuffer but put point @var{position} characters
169 from the beginning, rather than at the end.
171 @strong{Usage note:} The @var{initial-contents} argument and the
172 @var{default} argument are two alternative features for more or less the
173 same job. It does not make sense to use both features in a single call
174 to @code{read-from-minibuffer}. In general, we recommend using
175 @var{default}, since this permits the user to insert the default value
176 when it is wanted, but does not burden the user with deleting it from
177 the minibuffer on other occasions.
180 @defun read-string prompt &optional initial history default inherit-input-method
181 This function reads a string from the minibuffer and returns it. The
182 arguments @var{prompt} and @var{initial} are used as in
183 @code{read-from-minibuffer}. The keymap used is
184 @code{minibuffer-local-map}.
186 The optional argument @var{history}, if non-nil, specifies a history
187 list and optionally the initial position in the list. The optional
188 argument @var{default} specifies a default value to return if the user
189 enters null input; it should be a string. The optional argument
190 @var{inherit-input-method} specifies whether to inherit the current
191 buffer's input method.
193 This function is a simplified interface to the
194 @code{read-from-minibuffer} function:
198 (read-string @var{prompt} @var{initial} @var{history} @var{default} @var{inherit})
201 (read-from-minibuffer @var{prompt} @var{initial} nil nil
202 @var{history} @var{default} @var{inherit})))
210 @defvar minibuffer-allow-text-properties
211 If this variable is @code{nil}, then @code{read-from-minibuffer} strips
212 all text properties from the minibuffer input before returning it.
213 Since all minibuffer input uses @code{read-from-minibuffer}, this
214 variable applies to all minibuffer input.
216 Note that the completion functions discard text properties unconditionally,
217 regardless of the value of this variable.
220 @defvar minibuffer-local-map
221 This is the default local keymap for reading from the minibuffer. By
222 default, it makes the following bindings:
226 @code{exit-minibuffer}
229 @code{exit-minibuffer}
232 @code{abort-recursive-edit}
235 @code{next-history-element}
238 @code{previous-history-element}
241 @code{next-matching-history-element}
244 @code{previous-matching-history-element}
248 @c In version 18, initial is required
250 @defun read-no-blanks-input prompt &optional initial inherit-input-method
251 This function reads a string from the minibuffer, but does not allow
252 whitespace characters as part of the input: instead, those characters
253 terminate the input. The arguments @var{prompt}, @var{initial}, and
254 @var{inherit-input-method} are used as in @code{read-from-minibuffer}.
256 This is a simplified interface to the @code{read-from-minibuffer}
257 function, and passes the value of the @code{minibuffer-local-ns-map}
258 keymap as the @var{keymap} argument for that function. Since the keymap
259 @code{minibuffer-local-ns-map} does not rebind @kbd{C-q}, it @emph{is}
260 possible to put a space into the string, by quoting it.
264 (read-no-blanks-input @var{prompt} @var{initial})
266 (read-from-minibuffer @var{prompt} @var{initial} minibuffer-local-ns-map)
271 @defvar minibuffer-local-ns-map
272 This built-in variable is the keymap used as the minibuffer local keymap
273 in the function @code{read-no-blanks-input}. By default, it makes the
274 following bindings, in addition to those of @code{minibuffer-local-map}:
278 @cindex @key{SPC} in minibuffer
279 @code{exit-minibuffer}
282 @cindex @key{TAB} in minibuffer
283 @code{exit-minibuffer}
286 @cindex @kbd{?} in minibuffer
287 @code{self-insert-and-exit}
291 @node Object from Minibuffer
292 @section Reading Lisp Objects with the Minibuffer
294 This section describes functions for reading Lisp objects with the
297 @defun read-minibuffer prompt &optional initial
298 This function reads a Lisp object using the minibuffer, and returns it
299 without evaluating it. The arguments @var{prompt} and @var{initial} are
300 used as in @code{read-from-minibuffer}.
302 This is a simplified interface to the
303 @code{read-from-minibuffer} function:
307 (read-minibuffer @var{prompt} @var{initial})
309 (read-from-minibuffer @var{prompt} @var{initial} nil t)
313 Here is an example in which we supply the string @code{"(testing)"} as
319 "Enter an expression: " (format "%s" '(testing)))
321 ;; @r{Here is how the minibuffer is displayed:}
325 ---------- Buffer: Minibuffer ----------
326 Enter an expression: (testing)@point{}
327 ---------- Buffer: Minibuffer ----------
332 The user can type @key{RET} immediately to use the initial input as a
333 default, or can edit the input.
336 @defun eval-minibuffer prompt &optional initial
337 This function reads a Lisp expression using the minibuffer, evaluates
338 it, then returns the result. The arguments @var{prompt} and
339 @var{initial} are used as in @code{read-from-minibuffer}.
341 This function simply evaluates the result of a call to
342 @code{read-minibuffer}:
346 (eval-minibuffer @var{prompt} @var{initial})
348 (eval (read-minibuffer @var{prompt} @var{initial}))
353 @defun edit-and-eval-command prompt form
354 This function reads a Lisp expression in the minibuffer, and then
355 evaluates it. The difference between this command and
356 @code{eval-minibuffer} is that here the initial @var{form} is not
357 optional and it is treated as a Lisp object to be converted to printed
358 representation rather than as a string of text. It is printed with
359 @code{prin1}, so if it is a string, double-quote characters (@samp{"})
360 appear in the initial text. @xref{Output Functions}.
362 The first thing @code{edit-and-eval-command} does is to activate the
363 minibuffer with @var{prompt} as the prompt. Then it inserts the printed
364 representation of @var{form} in the minibuffer, and lets the user edit it.
365 When the user exits the minibuffer, the edited text is read with
366 @code{read} and then evaluated. The resulting value becomes the value
367 of @code{edit-and-eval-command}.
369 In the following example, we offer the user an expression with initial
370 text which is a valid form already:
374 (edit-and-eval-command "Please edit: " '(forward-word 1))
376 ;; @r{After evaluation of the preceding expression,}
377 ;; @r{the following appears in the minibuffer:}
381 ---------- Buffer: Minibuffer ----------
382 Please edit: (forward-word 1)@point{}
383 ---------- Buffer: Minibuffer ----------
388 Typing @key{RET} right away would exit the minibuffer and evaluate the
389 expression, thus moving point forward one word.
390 @code{edit-and-eval-command} returns @code{nil} in this example.
393 @node Minibuffer History
394 @section Minibuffer History
395 @cindex minibuffer history
398 A @dfn{minibuffer history list} records previous minibuffer inputs so
399 the user can reuse them conveniently. A history list is actually a
400 symbol, not a list; it is a variable whose value is a list of strings
401 (previous inputs), most recent first.
403 There are many separate history lists, used for different kinds of
404 inputs. It's the Lisp programmer's job to specify the right history
405 list for each use of the minibuffer.
407 The basic minibuffer input functions @code{read-from-minibuffer} and
408 @code{completing-read} both accept an optional argument named @var{hist}
409 which is how you specify the history list. Here are the possible
414 Use @var{variable} (a symbol) as the history list.
416 @item (@var{variable} . @var{startpos})
417 Use @var{variable} (a symbol) as the history list, and assume that the
418 initial history position is @var{startpos} (an integer, counting from
419 zero which specifies the most recent element of the history).
421 If you specify @var{startpos}, then you should also specify that element
422 of the history as the initial minibuffer contents, for consistency.
425 If you don't specify @var{hist}, then the default history list
426 @code{minibuffer-history} is used. For other standard history lists,
427 see below. You can also create your own history list variable; just
428 initialize it to @code{nil} before the first use.
430 Both @code{read-from-minibuffer} and @code{completing-read} add new
431 elements to the history list automatically, and provide commands to
432 allow the user to reuse items on the list. The only thing your program
433 needs to do to use a history list is to initialize it and to pass its
434 name to the input functions when you wish. But it is safe to modify the
435 list by hand when the minibuffer input functions are not using it.
437 Here are some of the standard minibuffer history list variables:
439 @defvar minibuffer-history
440 The default history list for minibuffer history input.
443 @defvar query-replace-history
444 A history list for arguments to @code{query-replace} (and similar
445 arguments to other commands).
448 @defvar file-name-history
449 A history list for file-name arguments.
452 @defvar buffer-name-history
453 @tindex buffer-name-history
454 A history list for buffer-name arguments.
457 @defvar regexp-history
458 A history list for regular expression arguments.
461 @defvar extended-command-history
462 A history list for arguments that are names of extended commands.
465 @defvar shell-command-history
466 A history list for arguments that are shell commands.
469 @defvar read-expression-history
470 A history list for arguments that are Lisp expressions to evaluate.
477 @dfn{Completion} is a feature that fills in the rest of a name
478 starting from an abbreviation for it. Completion works by comparing the
479 user's input against a list of valid names and determining how much of
480 the name is determined uniquely by what the user has typed. For
481 example, when you type @kbd{C-x b} (@code{switch-to-buffer}) and then
482 type the first few letters of the name of the buffer to which you wish
483 to switch, and then type @key{TAB} (@code{minibuffer-complete}), Emacs
484 extends the name as far as it can.
486 Standard Emacs commands offer completion for names of symbols, files,
487 buffers, and processes; with the functions in this section, you can
488 implement completion for other kinds of names.
490 The @code{try-completion} function is the basic primitive for
491 completion: it returns the longest determined completion of a given
492 initial string, with a given set of strings to match against.
494 The function @code{completing-read} provides a higher-level interface
495 for completion. A call to @code{completing-read} specifies how to
496 determine the list of valid names. The function then activates the
497 minibuffer with a local keymap that binds a few keys to commands useful
498 for completion. Other functions provide convenient simple interfaces
499 for reading certain kinds of names with completion.
502 * Basic Completion:: Low-level functions for completing strings.
503 (These are too low level to use the minibuffer.)
504 * Minibuffer Completion:: Invoking the minibuffer with completion.
505 * Completion Commands:: Minibuffer commands that do completion.
506 * High-Level Completion:: Convenient special cases of completion
507 (reading buffer name, file name, etc.)
508 * Reading File Names:: Using completion to read file names.
509 * Programmed Completion:: Finding the completions for a given file name.
512 @node Basic Completion
513 @subsection Basic Completion Functions
515 The two functions @code{try-completion} and @code{all-completions}
516 have nothing in themselves to do with minibuffers. We describe them in
517 this chapter so as to keep them near the higher-level completion
518 features that do use the minibuffer.
520 @defun try-completion string collection &optional predicate
521 This function returns the longest common substring of all possible
522 completions of @var{string} in @var{collection}. The value of
523 @var{collection} must be an alist, an obarray, or a function that
524 implements a virtual set of strings (see below).
526 Completion compares @var{string} against each of the permissible
527 completions specified by @var{collection}; if the beginning of the
528 permissible completion equals @var{string}, it matches. If no permissible
529 completions match, @code{try-completion} returns @code{nil}. If only
530 one permissible completion matches, and the match is exact, then
531 @code{try-completion} returns @code{t}. Otherwise, the value is the
532 longest initial sequence common to all the permissible completions that
535 If @var{collection} is an alist (@pxref{Association Lists}), the
536 @sc{car}s of the alist elements form the set of permissible completions.
538 @cindex obarray in completion
539 If @var{collection} is an obarray (@pxref{Creating Symbols}), the names
540 of all symbols in the obarray form the set of permissible completions. The
541 global variable @code{obarray} holds an obarray containing the names of
542 all interned Lisp symbols.
544 Note that the only valid way to make a new obarray is to create it
545 empty and then add symbols to it one by one using @code{intern}.
546 Also, you cannot intern a given symbol in more than one obarray.
548 If the argument @var{predicate} is non-@code{nil}, then it must be a
549 function of one argument. It is used to test each possible match, and
550 the match is accepted only if @var{predicate} returns non-@code{nil}.
551 The argument given to @var{predicate} is either a cons cell from the alist
552 (the @sc{car} of which is a string) or else it is a symbol (@emph{not} a
553 symbol name) from the obarray.
555 You can also use a symbol that is a function as @var{collection}. Then
556 the function is solely responsible for performing completion;
557 @code{try-completion} returns whatever this function returns. The
558 function is called with three arguments: @var{string}, @var{predicate}
559 and @code{nil}. (The reason for the third argument is so that the same
560 function can be used in @code{all-completions} and do the appropriate
561 thing in either case.) @xref{Programmed Completion}.
563 In the first of the following examples, the string @samp{foo} is
564 matched by three of the alist @sc{car}s. All of the matches begin with
565 the characters @samp{fooba}, so that is the result. In the second
566 example, there is only one possible match, and it is exact, so the value
573 '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)))
578 (try-completion "foo" '(("barfoo" 2) ("foo" 3)))
583 In the following example, numerous symbols begin with the characters
584 @samp{forw}, and all of them begin with the word @samp{forward}. In
585 most of the symbols, this is followed with a @samp{-}, but not in all,
586 so no more than @samp{forward} can be completed.
590 (try-completion "forw" obarray)
595 Finally, in the following example, only two of the three possible
596 matches pass the predicate @code{test} (the string @samp{foobaz} is
597 too short). Both of those begin with the string @samp{foobar}.
602 (> (length (car s)) 6))
608 '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))
615 @defun all-completions string collection &optional predicate nospace
616 This function returns a list of all possible completions of
617 @var{string}. The arguments to this function (aside from @var{nospace})
618 are the same as those of @code{try-completion}. If @var{nospace} is
619 non-@code{nil}, completions that start with a space are ignored unless
620 @var{string} also starts with a space.
622 If @var{collection} is a function, it is called with three arguments:
623 @var{string}, @var{predicate} and @code{t}; then @code{all-completions}
624 returns whatever the function returns. @xref{Programmed Completion}.
626 Here is an example, using the function @code{test} shown in the
627 example for @code{try-completion}:
632 (> (length (car s)) 6))
639 '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))
641 @result{} ("foobar1" "foobar2")
646 @defvar completion-ignore-case
647 If the value of this variable is
648 non-@code{nil}, Emacs does not consider case significant in completion.
651 @node Minibuffer Completion
652 @subsection Completion and the Minibuffer
654 This section describes the basic interface for reading from the
655 minibuffer with completion.
657 @defun completing-read prompt collection &optional predicate require-match initial hist default inherit-input-method
658 This function reads a string in the minibuffer, assisting the user by
659 providing completion. It activates the minibuffer with prompt
660 @var{prompt}, which must be a string.
662 The actual completion is done by passing @var{collection} and
663 @var{predicate} to the function @code{try-completion}. This happens in
664 certain commands bound in the local keymaps used for completion.
666 If @var{require-match} is @code{nil}, the exit commands work regardless
667 of the input in the minibuffer. If @var{require-match} is @code{t}, the
668 usual minibuffer exit commands won't exit unless the input completes to
669 an element of @var{collection}. If @var{require-match} is neither
670 @code{nil} nor @code{t}, then the exit commands won't exit unless the
671 input already in the buffer matches an element of @var{collection}.
673 However, empty input is always permitted, regardless of the value of
674 @var{require-match}; in that case, @code{completing-read} returns
675 @var{default}. The value of @var{default} (if non-@code{nil}) is also
676 available to the user through the history commands.
678 The user can exit with null input by typing @key{RET} with an empty
679 minibuffer. Then @code{completing-read} returns @code{""}. This is how
680 the user requests whatever default the command uses for the value being
681 read. The user can return using @key{RET} in this way regardless of the
682 value of @var{require-match}, and regardless of whether the empty string
683 is included in @var{collection}.
685 The function @code{completing-read} works by calling
686 @code{read-minibuffer}. It uses @code{minibuffer-local-completion-map}
687 as the keymap if @var{require-match} is @code{nil}, and uses
688 @code{minibuffer-local-must-match-map} if @var{require-match} is
689 non-@code{nil}. @xref{Completion Commands}.
691 The argument @var{hist} specifies which history list variable to use for
692 saving the input and for minibuffer history commands. It defaults to
693 @code{minibuffer-history}. @xref{Minibuffer History}.
695 If @var{initial} is non-@code{nil}, @code{completing-read} inserts it
696 into the minibuffer as part of the input. Then it allows the user to
697 edit the input, providing several commands to attempt completion.
698 In most cases, we recommend using @var{default}, and not @var{initial}.
700 If the argument @var{inherit-input-method} is non-@code{nil}, then the
701 minibuffer inherits the current input method (@pxref{Input
702 Methods}) and the setting of @code{enable-multibyte-characters}
703 (@pxref{Text Representations}) from whichever buffer was current before
704 entering the minibuffer.
706 Completion ignores case when comparing the input against the possible
707 matches, if the built-in variable @code{completion-ignore-case} is
708 non-@code{nil}. @xref{Basic Completion}.
710 Here's an example of using @code{completing-read}:
716 '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))
721 ;; @r{After evaluation of the preceding expression,}
722 ;; @r{the following appears in the minibuffer:}
724 ---------- Buffer: Minibuffer ----------
725 Complete a foo: fo@point{}
726 ---------- Buffer: Minibuffer ----------
731 If the user then types @kbd{@key{DEL} @key{DEL} b @key{RET}},
732 @code{completing-read} returns @code{barfoo}.
734 The @code{completing-read} function binds three variables to pass
735 information to the commands that actually do completion. These
736 variables are @code{minibuffer-completion-table},
737 @code{minibuffer-completion-predicate} and
738 @code{minibuffer-completion-confirm}. For more information about them,
739 see @ref{Completion Commands}.
742 @node Completion Commands
743 @subsection Minibuffer Commands that Do Completion
745 This section describes the keymaps, commands and user options used in
746 the minibuffer to do completion.
748 @defvar minibuffer-local-completion-map
749 @code{completing-read} uses this value as the local keymap when an
750 exact match of one of the completions is not required. By default, this
751 keymap makes the following bindings:
755 @code{minibuffer-completion-help}
758 @code{minibuffer-complete-word}
761 @code{minibuffer-complete}
765 with other characters bound as in @code{minibuffer-local-map}
766 (@pxref{Text from Minibuffer}).
769 @defvar minibuffer-local-must-match-map
770 @code{completing-read} uses this value as the local keymap when an
771 exact match of one of the completions is required. Therefore, no keys
772 are bound to @code{exit-minibuffer}, the command that exits the
773 minibuffer unconditionally. By default, this keymap makes the following
778 @code{minibuffer-completion-help}
781 @code{minibuffer-complete-word}
784 @code{minibuffer-complete}
787 @code{minibuffer-complete-and-exit}
790 @code{minibuffer-complete-and-exit}
794 with other characters bound as in @code{minibuffer-local-map}.
797 @defvar minibuffer-completion-table
798 The value of this variable is the alist or obarray used for completion
799 in the minibuffer. This is the global variable that contains what
800 @code{completing-read} passes to @code{try-completion}. It is used by
801 minibuffer completion commands such as @code{minibuffer-complete-word}.
804 @defvar minibuffer-completion-predicate
805 This variable's value is the predicate that @code{completing-read}
806 passes to @code{try-completion}. The variable is also used by the other
807 minibuffer completion functions.
810 @deffn Command minibuffer-complete-word
811 This function completes the minibuffer contents by at most a single
812 word. Even if the minibuffer contents have only one completion,
813 @code{minibuffer-complete-word} does not add any characters beyond the
814 first character that is not a word constituent. @xref{Syntax Tables}.
817 @deffn Command minibuffer-complete
818 This function completes the minibuffer contents as far as possible.
821 @deffn Command minibuffer-complete-and-exit
822 This function completes the minibuffer contents, and exits if
823 confirmation is not required, i.e., if
824 @code{minibuffer-completion-confirm} is @code{nil}. If confirmation
825 @emph{is} required, it is given by repeating this command
826 immediately---the command is programmed to work without confirmation
827 when run twice in succession.
830 @defvar minibuffer-completion-confirm
831 When the value of this variable is non-@code{nil}, Emacs asks for
832 confirmation of a completion before exiting the minibuffer. The
833 function @code{minibuffer-complete-and-exit} checks the value of this
834 variable before it exits.
837 @deffn Command minibuffer-completion-help
838 This function creates a list of the possible completions of the
839 current minibuffer contents. It works by calling @code{all-completions}
840 using the value of the variable @code{minibuffer-completion-table} as
841 the @var{collection} argument, and the value of
842 @code{minibuffer-completion-predicate} as the @var{predicate} argument.
843 The list of completions is displayed as text in a buffer named
844 @samp{*Completions*}.
847 @defun display-completion-list completions
848 This function displays @var{completions} to the stream in
849 @code{standard-output}, usually a buffer. (@xref{Read and Print}, for more
850 information about streams.) The argument @var{completions} is normally
851 a list of completions just returned by @code{all-completions}, but it
852 does not have to be. Each element may be a symbol or a string, either
853 of which is simply printed, or a list of two strings, which is printed
854 as if the strings were concatenated.
856 This function is called by @code{minibuffer-completion-help}. The
857 most common way to use it is together with
858 @code{with-output-to-temp-buffer}, like this:
861 (with-output-to-temp-buffer "*Completions*"
862 (display-completion-list
863 (all-completions (buffer-string) my-alist)))
867 @defopt completion-auto-help
868 If this variable is non-@code{nil}, the completion commands
869 automatically display a list of possible completions whenever nothing
870 can be completed because the next character is not uniquely determined.
873 @node High-Level Completion
874 @subsection High-Level Completion Functions
876 This section describes the higher-level convenient functions for
877 reading certain sorts of names with completion.
879 In most cases, you should not call these functions in the middle of a
880 Lisp function. When possible, do all minibuffer input as part of
881 reading the arguments for a command, in the @code{interactive}
882 specification. @xref{Defining Commands}.
884 @defun read-buffer prompt &optional default existing
885 This function reads the name of a buffer and returns it as a string.
886 The argument @var{default} is the default name to use, the value to
887 return if the user exits with an empty minibuffer. If non-@code{nil},
888 it should be a string or a buffer. It is mentioned in the prompt, but
889 is not inserted in the minibuffer as initial input.
891 If @var{existing} is non-@code{nil}, then the name specified must be
892 that of an existing buffer. The usual commands to exit the minibuffer
893 do not exit if the text is not valid, and @key{RET} does completion to
894 attempt to find a valid name. (However, @var{default} is not checked
895 for validity; it is returned, whatever it is, if the user exits with the
898 In the following example, the user enters @samp{minibuffer.t}, and
899 then types @key{RET}. The argument @var{existing} is @code{t}, and the
900 only buffer name starting with the given input is
901 @samp{minibuffer.texi}, so that name is the value.
904 (read-buffer "Buffer name? " "foo" t)
906 ;; @r{After evaluation of the preceding expression,}
907 ;; @r{the following prompt appears,}
908 ;; @r{with an empty minibuffer:}
912 ---------- Buffer: Minibuffer ----------
913 Buffer name? (default foo) @point{}
914 ---------- Buffer: Minibuffer ----------
918 ;; @r{The user types @kbd{minibuffer.t @key{RET}}.}
919 @result{} "minibuffer.texi"
924 @defvar read-buffer-function
925 This variable specifies how to read buffer names. For example, if you
926 set this variable to @code{iswitchb-read-buffer}, all Emacs commands
927 that call @code{read-buffer} to read a buffer name will actually use the
928 @code{iswitchb} package to read it.
931 @defun read-command prompt &optional default
932 This function reads the name of a command and returns it as a Lisp
933 symbol. The argument @var{prompt} is used as in
934 @code{read-from-minibuffer}. Recall that a command is anything for
935 which @code{commandp} returns @code{t}, and a command name is a symbol
936 for which @code{commandp} returns @code{t}. @xref{Interactive Call}.
938 The argument @var{default} specifies what to return if the user enters
939 null input. It can be a symbol or a string; if it is a string,
940 @code{read-command} interns it before returning it. If @var{default} is
941 @code{nil}, that means no default has been specified; then if the user
942 enters null input, the return value is @code{nil}.
945 (read-command "Command name? ")
948 ;; @r{After evaluation of the preceding expression,}
949 ;; @r{the following prompt appears with an empty minibuffer:}
953 ---------- Buffer: Minibuffer ----------
955 ---------- Buffer: Minibuffer ----------
960 If the user types @kbd{forward-c @key{RET}}, then this function returns
963 The @code{read-command} function is a simplified interface to
964 @code{completing-read}. It uses the variable @code{obarray} so as to
965 complete in the set of extant Lisp symbols, and it uses the
966 @code{commandp} predicate so as to accept only command names:
968 @cindex @code{commandp} example
971 (read-command @var{prompt})
973 (intern (completing-read @var{prompt} obarray
979 @defun read-variable prompt &optional default
980 This function reads the name of a user variable and returns it as a
983 The argument @var{default} specifies what to return if the user enters
984 null input. It can be a symbol or a string; if it is a string,
985 @code{read-variable} interns it before returning it. If @var{default}
986 is @code{nil}, that means no default has been specified; then if the
987 user enters null input, the return value is @code{nil}.
991 (read-variable "Variable name? ")
993 ;; @r{After evaluation of the preceding expression,}
994 ;; @r{the following prompt appears,}
995 ;; @r{with an empty minibuffer:}
999 ---------- Buffer: Minibuffer ----------
1000 Variable name? @point{}
1001 ---------- Buffer: Minibuffer ----------
1006 If the user then types @kbd{fill-p @key{RET}}, @code{read-variable}
1007 returns @code{fill-prefix}.
1009 This function is similar to @code{read-command}, but uses the
1010 predicate @code{user-variable-p} instead of @code{commandp}:
1012 @cindex @code{user-variable-p} example
1015 (read-variable @var{prompt})
1018 (completing-read @var{prompt} obarray
1019 'user-variable-p t nil))
1024 See also the functions @code{read-coding-system} and
1025 @code{read-non-nil-coding-system}, in @ref{User-Chosen Coding Systems}.
1027 @node Reading File Names
1028 @subsection Reading File Names
1030 Here is another high-level completion function, designed for reading a
1031 file name. It provides special features including automatic insertion
1032 of the default directory.
1034 @defun read-file-name prompt &optional directory default existing initial
1035 This function reads a file name in the minibuffer, prompting with
1036 @var{prompt} and providing completion. If @var{default} is
1037 non-@code{nil}, then the function returns @var{default} if the user just
1038 types @key{RET}. @var{default} is not checked for validity; it is
1039 returned, whatever it is, if the user exits with the minibuffer empty.
1041 If @var{existing} is non-@code{nil}, then the user must specify the name
1042 of an existing file; @key{RET} performs completion to make the name
1043 valid if possible, and then refuses to exit if it is not valid. If the
1044 value of @var{existing} is neither @code{nil} nor @code{t}, then
1045 @key{RET} also requires confirmation after completion. If
1046 @var{existing} is @code{nil}, then the name of a nonexistent file is
1049 The argument @var{directory} specifies the directory to use for
1050 completion of relative file names. If @code{insert-default-directory}
1051 is non-@code{nil}, @var{directory} is also inserted in the minibuffer as
1052 initial input. It defaults to the current buffer's value of
1053 @code{default-directory}.
1056 If you specify @var{initial}, that is an initial file name to insert in
1057 the buffer (after @var{directory}, if that is inserted). In this
1058 case, point goes at the beginning of @var{initial}. The default for
1059 @var{initial} is @code{nil}---don't insert any file name. To see what
1060 @var{initial} does, try the command @kbd{C-x C-v}. @strong{Note:} we
1061 recommend using @var{default} rather than @var{initial} in most cases.
1067 (read-file-name "The file is ")
1069 ;; @r{After evaluation of the preceding expression,}
1070 ;; @r{the following appears in the minibuffer:}
1074 ---------- Buffer: Minibuffer ----------
1075 The file is /gp/gnu/elisp/@point{}
1076 ---------- Buffer: Minibuffer ----------
1081 Typing @kbd{manual @key{TAB}} results in the following:
1085 ---------- Buffer: Minibuffer ----------
1086 The file is /gp/gnu/elisp/manual.texi@point{}
1087 ---------- Buffer: Minibuffer ----------
1091 @c Wordy to avoid overfull hbox in smallbook mode.
1093 If the user types @key{RET}, @code{read-file-name} returns the file name
1094 as the string @code{"/gp/gnu/elisp/manual.texi"}.
1097 @defopt insert-default-directory
1098 This variable is used by @code{read-file-name}. Its value controls
1099 whether @code{read-file-name} starts by placing the name of the default
1100 directory in the minibuffer, plus the initial file name if any. If the
1101 value of this variable is @code{nil}, then @code{read-file-name} does
1102 not place any initial input in the minibuffer (unless you specify
1103 initial input with the @var{initial} argument). In that case, the
1104 default directory is still used for completion of relative file names,
1105 but is not displayed.
1111 ;; @r{Here the minibuffer starts out with the default directory.}
1112 (let ((insert-default-directory t))
1113 (read-file-name "The file is "))
1117 ---------- Buffer: Minibuffer ----------
1118 The file is ~lewis/manual/@point{}
1119 ---------- Buffer: Minibuffer ----------
1123 ;; @r{Here the minibuffer is empty and only the prompt}
1124 ;; @r{appears on its line.}
1125 (let ((insert-default-directory nil))
1126 (read-file-name "The file is "))
1130 ---------- Buffer: Minibuffer ----------
1131 The file is @point{}
1132 ---------- Buffer: Minibuffer ----------
1137 @node Programmed Completion
1138 @subsection Programmed Completion
1139 @cindex programmed completion
1141 Sometimes it is not possible to create an alist or an obarray
1142 containing all the intended possible completions. In such a case, you
1143 can supply your own function to compute the completion of a given string.
1144 This is called @dfn{programmed completion}.
1146 To use this feature, pass a symbol with a function definition as the
1147 @var{collection} argument to @code{completing-read}. The function
1148 @code{completing-read} arranges to pass your completion function along
1149 to @code{try-completion} and @code{all-completions}, which will then let
1150 your function do all the work.
1152 The completion function should accept three arguments:
1156 The string to be completed.
1159 The predicate function to filter possible matches, or @code{nil} if
1160 none. Your function should call the predicate for each possible match,
1161 and ignore the possible match if the predicate returns @code{nil}.
1164 A flag specifying the type of operation.
1167 There are three flag values for three operations:
1171 @code{nil} specifies @code{try-completion}. The completion function
1172 should return the completion of the specified string, or @code{t} if the
1173 string is a unique and exact match already, or @code{nil} if the string
1174 matches no possibility.
1176 If the string is an exact match for one possibility, but also matches
1177 other longer possibilities, the function should return the string, not
1181 @code{t} specifies @code{all-completions}. The completion function
1182 should return a list of all possible completions of the specified
1186 @code{lambda} specifies a test for an exact match. The completion
1187 function should return @code{t} if the specified string is an exact
1188 match for some possibility; @code{nil} otherwise.
1191 It would be consistent and clean for completion functions to allow
1192 lambda expressions (lists that are functions) as well as function
1193 symbols as @var{collection}, but this is impossible. Lists as
1194 completion tables are already assigned another meaning---as alists. It
1195 would be unreliable to fail to handle an alist normally because it is
1196 also a possible function. So you must arrange for any function you wish
1197 to use for completion to be encapsulated in a symbol.
1199 Emacs uses programmed completion when completing file names.
1200 @xref{File Name Completion}.
1202 @node Yes-or-No Queries
1203 @section Yes-or-No Queries
1204 @cindex asking the user questions
1205 @cindex querying the user
1206 @cindex yes-or-no questions
1208 This section describes functions used to ask the user a yes-or-no
1209 question. The function @code{y-or-n-p} can be answered with a single
1210 character; it is useful for questions where an inadvertent wrong answer
1211 will not have serious consequences. @code{yes-or-no-p} is suitable for
1212 more momentous questions, since it requires three or four characters to
1215 If either of these functions is called in a command that was invoked
1216 using the mouse---more precisely, if @code{last-nonmenu-event}
1217 (@pxref{Command Loop Info}) is either @code{nil} or a list---then it
1218 uses a dialog box or pop-up menu to ask the question. Otherwise, it
1219 uses keyboard input. You can force use of the mouse or use of keyboard
1220 input by binding @code{last-nonmenu-event} to a suitable value around
1223 Strictly speaking, @code{yes-or-no-p} uses the minibuffer and
1224 @code{y-or-n-p} does not; but it seems best to describe them together.
1226 @defun y-or-n-p prompt
1227 This function asks the user a question, expecting input in the echo
1228 area. It returns @code{t} if the user types @kbd{y}, @code{nil} if the
1229 user types @kbd{n}. This function also accepts @key{SPC} to mean yes
1230 and @key{DEL} to mean no. It accepts @kbd{C-]} to mean ``quit'', like
1231 @kbd{C-g}, because the question might look like a minibuffer and for
1232 that reason the user might try to use @kbd{C-]} to get out. The answer
1233 is a single character, with no @key{RET} needed to terminate it. Upper
1234 and lower case are equivalent.
1236 ``Asking the question'' means printing @var{prompt} in the echo area,
1237 followed by the string @w{@samp{(y or n) }}. If the input is not one of
1238 the expected answers (@kbd{y}, @kbd{n}, @kbd{@key{SPC}},
1239 @kbd{@key{DEL}}, or something that quits), the function responds
1240 @samp{Please answer y or n.}, and repeats the request.
1242 This function does not actually use the minibuffer, since it does not
1243 allow editing of the answer. It actually uses the echo area (@pxref{The
1244 Echo Area}), which uses the same screen space as the minibuffer. The
1245 cursor moves to the echo area while the question is being asked.
1247 The answers and their meanings, even @samp{y} and @samp{n}, are not
1248 hardwired. The keymap @code{query-replace-map} specifies them.
1249 @xref{Search and Replace}.
1251 In the following example, the user first types @kbd{q}, which is
1252 invalid. At the next prompt the user types @kbd{y}.
1256 (y-or-n-p "Do you need a lift? ")
1258 ;; @r{After evaluation of the preceding expression,}
1259 ;; @r{the following prompt appears in the echo area:}
1263 ---------- Echo area ----------
1264 Do you need a lift? (y or n)
1265 ---------- Echo area ----------
1268 ;; @r{If the user then types @kbd{q}, the following appears:}
1271 ---------- Echo area ----------
1272 Please answer y or n. Do you need a lift? (y or n)
1273 ---------- Echo area ----------
1276 ;; @r{When the user types a valid answer,}
1277 ;; @r{it is displayed after the question:}
1280 ---------- Echo area ----------
1281 Do you need a lift? (y or n) y
1282 ---------- Echo area ----------
1287 We show successive lines of echo area messages, but only one actually
1288 appears on the screen at a time.
1291 @defun y-or-n-p-with-timeout prompt seconds default-value
1292 Like @code{y-or-n-p}, except that if the user fails to answer within
1293 @var{seconds} seconds, this function stops waiting and returns
1294 @var{default-value}. It works by setting up a timer; see @ref{Timers}.
1295 The argument @var{seconds} may be an integer or a floating point number.
1298 @defun yes-or-no-p prompt
1299 This function asks the user a question, expecting input in the
1300 minibuffer. It returns @code{t} if the user enters @samp{yes},
1301 @code{nil} if the user types @samp{no}. The user must type @key{RET} to
1302 finalize the response. Upper and lower case are equivalent.
1304 @code{yes-or-no-p} starts by displaying @var{prompt} in the echo area,
1305 followed by @w{@samp{(yes or no) }}. The user must type one of the
1306 expected responses; otherwise, the function responds @samp{Please answer
1307 yes or no.}, waits about two seconds and repeats the request.
1309 @code{yes-or-no-p} requires more work from the user than
1310 @code{y-or-n-p} and is appropriate for more crucial decisions.
1316 (yes-or-no-p "Do you really want to remove everything? ")
1318 ;; @r{After evaluation of the preceding expression,}
1319 ;; @r{the following prompt appears,}
1320 ;; @r{with an empty minibuffer:}
1324 ---------- Buffer: minibuffer ----------
1325 Do you really want to remove everything? (yes or no)
1326 ---------- Buffer: minibuffer ----------
1331 If the user first types @kbd{y @key{RET}}, which is invalid because this
1332 function demands the entire word @samp{yes}, it responds by displaying
1333 these prompts, with a brief pause between them:
1337 ---------- Buffer: minibuffer ----------
1338 Please answer yes or no.
1339 Do you really want to remove everything? (yes or no)
1340 ---------- Buffer: minibuffer ----------
1345 @node Multiple Queries
1346 @section Asking Multiple Y-or-N Questions
1348 When you have a series of similar questions to ask, such as ``Do you
1349 want to save this buffer'' for each buffer in turn, you should use
1350 @code{map-y-or-n-p} to ask the collection of questions, rather than
1351 asking each question individually. This gives the user certain
1352 convenient facilities such as the ability to answer the whole series at
1355 @defun map-y-or-n-p prompter actor list &optional help action-alist no-cursor-in-echo-area
1356 This function asks the user a series of questions, reading a
1357 single-character answer in the echo area for each one.
1359 The value of @var{list} specifies the objects to ask questions about.
1360 It should be either a list of objects or a generator function. If it is
1361 a function, it should expect no arguments, and should return either the
1362 next object to ask about, or @code{nil} meaning stop asking questions.
1364 The argument @var{prompter} specifies how to ask each question. If
1365 @var{prompter} is a string, the question text is computed like this:
1368 (format @var{prompter} @var{object})
1372 where @var{object} is the next object to ask about (as obtained from
1375 If not a string, @var{prompter} should be a function of one argument
1376 (the next object to ask about) and should return the question text. If
1377 the value is a string, that is the question to ask the user. The
1378 function can also return @code{t} meaning do act on this object (and
1379 don't ask the user), or @code{nil} meaning ignore this object (and don't
1382 The argument @var{actor} says how to act on the answers that the user
1383 gives. It should be a function of one argument, and it is called with
1384 each object that the user says yes for. Its argument is always an
1385 object obtained from @var{list}.
1387 If the argument @var{help} is given, it should be a list of this form:
1390 (@var{singular} @var{plural} @var{action})
1394 where @var{singular} is a string containing a singular noun that
1395 describes the objects conceptually being acted on, @var{plural} is the
1396 corresponding plural noun, and @var{action} is a transitive verb
1397 describing what @var{actor} does.
1399 If you don't specify @var{help}, the default is @code{("object"
1400 "objects" "act on")}.
1402 Each time a question is asked, the user may enter @kbd{y}, @kbd{Y}, or
1403 @key{SPC} to act on that object; @kbd{n}, @kbd{N}, or @key{DEL} to skip
1404 that object; @kbd{!} to act on all following objects; @key{ESC} or
1405 @kbd{q} to exit (skip all following objects); @kbd{.} (period) to act on
1406 the current object and then exit; or @kbd{C-h} to get help. These are
1407 the same answers that @code{query-replace} accepts. The keymap
1408 @code{query-replace-map} defines their meaning for @code{map-y-or-n-p}
1409 as well as for @code{query-replace}; see @ref{Search and Replace}.
1411 You can use @var{action-alist} to specify additional possible answers
1412 and what they mean. It is an alist of elements of the form
1413 @code{(@var{char} @var{function} @var{help})}, each of which defines one
1414 additional answer. In this element, @var{char} is a character (the
1415 answer); @var{function} is a function of one argument (an object from
1416 @var{list}); @var{help} is a string.
1418 When the user responds with @var{char}, @code{map-y-or-n-p} calls
1419 @var{function}. If it returns non-@code{nil}, the object is considered
1420 ``acted upon'', and @code{map-y-or-n-p} advances to the next object in
1421 @var{list}. If it returns @code{nil}, the prompt is repeated for the
1424 Normally, @code{map-y-or-n-p} binds @code{cursor-in-echo-area} while
1425 prompting. But if @var{no-cursor-in-echo-area} is non-@code{nil}, it
1428 If @code{map-y-or-n-p} is called in a command that was invoked using the
1429 mouse---more precisely, if @code{last-nonmenu-event} (@pxref{Command
1430 Loop Info}) is either @code{nil} or a list---then it uses a dialog box
1431 or pop-up menu to ask the question. In this case, it does not use
1432 keyboard input or the echo area. You can force use of the mouse or use
1433 of keyboard input by binding @code{last-nonmenu-event} to a suitable
1434 value around the call.
1436 The return value of @code{map-y-or-n-p} is the number of objects acted on.
1439 @node Reading a Password
1440 @section Reading a Password
1441 @cindex passwords, reading
1443 To read a password to pass to another program, you can use the
1444 function @code{read-passwd}.
1447 @defun read-passwd prompt &optional confirm default
1448 This function reads a password, prompting with @var{prompt}. It does
1449 not echo the password as the user types it; instead, it echoes @samp{.}
1450 for each character in the password.
1452 The optional argument @var{confirm}, if non-@code{nil}, says to read the
1453 password twice and insist it must be the same both times. If it isn't
1454 the same, the user has to type it over and over until the last two
1457 The optional argument @var{default} specifies the default password to
1458 return if the user enters empty input. If @var{default} is @code{nil},
1459 then @code{read-passwd} returns the null string in that case.
1462 @node Minibuffer Misc
1463 @section Minibuffer Miscellany
1465 This section describes some basic functions and variables related to
1468 @deffn Command exit-minibuffer
1469 This command exits the active minibuffer. It is normally bound to
1470 keys in minibuffer local keymaps.
1473 @deffn Command self-insert-and-exit
1474 This command exits the active minibuffer after inserting the last
1475 character typed on the keyboard (found in @code{last-command-char};
1476 @pxref{Command Loop Info}).
1479 @deffn Command previous-history-element n
1480 This command replaces the minibuffer contents with the value of the
1481 @var{n}th previous (older) history element.
1484 @deffn Command next-history-element n
1485 This command replaces the minibuffer contents with the value of the
1486 @var{n}th more recent history element.
1489 @deffn Command previous-matching-history-element pattern n
1490 This command replaces the minibuffer contents with the value of the
1491 @var{n}th previous (older) history element that matches @var{pattern} (a
1492 regular expression).
1495 @deffn Command next-matching-history-element pattern n
1496 This command replaces the minibuffer contents with the value of the
1497 @var{n}th next (newer) history element that matches @var{pattern} (a
1498 regular expression).
1501 @defun minibuffer-prompt
1502 This function returns the prompt string of the currently active
1503 minibuffer. If no minibuffer is active, it returns @code{nil}.
1506 @tindex minibuffer-prompt-end
1507 @defun minibuffer-prompt-end
1508 This function, available starting in Emacs 21, returns the current
1509 position of the end of the minibuffer prompt, if a minibuffer is
1510 current. Otherwise, it returns zero.
1513 @defun minubuffer-prompt-width
1514 This function returns the current display-width of the minibuffer
1515 prompt, if a minibuffer is current. Otherwise, it returns zero.
1518 @defvar minibuffer-setup-hook
1519 This is a normal hook that is run whenever the minibuffer is entered.
1523 @defvar minibuffer-exit-hook
1524 This is a normal hook that is run whenever the minibuffer is exited.
1528 @defvar minibuffer-help-form
1529 The current value of this variable is used to rebind @code{help-form}
1530 locally inside the minibuffer (@pxref{Help Functions}).
1533 @defun active-minibuffer-window
1534 This function returns the currently active minibuffer window, or
1535 @code{nil} if none is currently active.
1538 @defun minibuffer-window &optional frame
1539 This function returns the minibuffer window used for frame @var{frame}.
1540 If @var{frame} is @code{nil}, that stands for the current frame. Note
1541 that the minibuffer window used by a frame need not be part of that
1542 frame---a frame that has no minibuffer of its own necessarily uses some
1543 other frame's minibuffer window.
1547 @defun window-minibuffer-p window
1548 This function returns non-@code{nil} if @var{window} is a minibuffer window.
1551 It is not correct to determine whether a given window is a minibuffer by
1552 comparing it with the result of @code{(minibuffer-window)}, because
1553 there can be more than one minibuffer window if there is more than one
1556 @defun minibuffer-window-active-p window
1557 This function returns non-@code{nil} if @var{window}, assumed to be
1558 a minibuffer window, is currently active.
1561 @defvar minibuffer-scroll-window
1562 If the value of this variable is non-@code{nil}, it should be a window
1563 object. When the function @code{scroll-other-window} is called in the
1564 minibuffer, it scrolls this window.
1567 Finally, some functions and variables deal with recursive minibuffers
1568 (@pxref{Recursive Editing}):
1570 @defun minibuffer-depth
1571 This function returns the current depth of activations of the
1572 minibuffer, a nonnegative integer. If no minibuffers are active, it
1576 @defopt enable-recursive-minibuffers
1577 If this variable is non-@code{nil}, you can invoke commands (such as
1578 @code{find-file}) that use minibuffers even while the minibuffer window
1579 is active. Such invocation produces a recursive editing level for a new
1580 minibuffer. The outer-level minibuffer is invisible while you are
1581 editing the inner one.
1583 If this variable is @code{nil}, you cannot invoke minibuffer
1584 commands when the minibuffer window is active, not even if you switch to
1585 another window to do it.
1589 If a command name has a property @code{enable-recursive-minibuffers}
1590 that is non-@code{nil}, then the command can use the minibuffer to read
1591 arguments even if it is invoked from the minibuffer. The minibuffer
1592 command @code{next-matching-history-element} (normally @kbd{M-s} in the
1593 minibuffer) uses this feature.