--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/man/lispref/minibuf.texi	Mon Aug 13 08:45:50 2007 +0200
@@ -0,0 +1,1467 @@
+@c -*-texinfo-*-
+@c This is part of the XEmacs Lisp Reference Manual.
+@c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. 
+@c See the file lispref.texi for copying conditions.
+@setfilename ../../info/minibuf.info
+@node Minibuffers, Command Loop, Read and Print, Top
+@chapter Minibuffers
+@cindex arguments, reading
+@cindex complex arguments
+@cindex minibuffer
+
+  A @dfn{minibuffer} is a special buffer that XEmacs commands use to read
+arguments more complicated than the single numeric prefix argument.
+These arguments include file names, buffer names, and command names (as
+in @kbd{M-x}).  The minibuffer is displayed on the bottom line of the
+frame, in the same place as the echo area, but only while it is in
+use for reading an argument.
+
+@menu
+* Intro to Minibuffers::      Basic information about minibuffers.
+* Text from Minibuffer::      How to read a straight text string.
+* Object from Minibuffer::    How to read a Lisp object or expression.
+* Minibuffer History::	      Recording previous minibuffer inputs
+				so the user can reuse them.
+* Completion::                How to invoke and customize completion.
+* Yes-or-No Queries::         Asking a question with a simple answer.
+* Multiple Queries::	      Asking a series of similar questions.
+* Minibuffer Misc::           Various customization hooks and variables.
+@end menu
+
+@node Intro to Minibuffers
+@section Introduction to Minibuffers
+
+  In most ways, a minibuffer is a normal XEmacs buffer.  Most operations
+@emph{within} a buffer, such as editing commands, work normally in a
+minibuffer.  However, many operations for managing buffers do not apply
+to minibuffers.  The name of a minibuffer always has the form @w{@samp{
+*Minibuf-@var{number}}}, and it cannot be changed.  Minibuffers are
+displayed only in special windows used only for minibuffers; these
+windows always appear at the bottom of a frame.  (Sometime frames have
+no minibuffer window, and sometimes a special kind of frame contains
+nothing but a minibuffer window; see @ref{Minibuffers and Frames}.)
+
+  The minibuffer's window is normally a single line.  You can resize it
+temporarily with the window sizing commands; it reverts to its normal
+size when the minibuffer is exited.  You can resize it permanently by
+using the window sizing commands in the frame's other window, when the
+minibuffer is not active.  If the frame contains just a minibuffer, you
+can change the minibuffer's size by changing the frame's size.
+
+  If a command uses a minibuffer while there is an active minibuffer,
+this is called a @dfn{recursive minibuffer}.  The first minibuffer is
+named @w{@samp{ *Minibuf-0*}}.  Recursive minibuffers are named by
+incrementing the number at the end of the name.  (The names begin with a
+space so that they won't show up in normal buffer lists.)  Of several
+recursive minibuffers, the innermost (or most recently entered) is the
+active minibuffer.  We usually call this ``the'' minibuffer.  You can
+permit or forbid recursive minibuffers by setting the variable
+@code{enable-recursive-minibuffers}.
+
+  Like other buffers, a minibuffer may use any of several local keymaps
+(@pxref{Keymaps}); these contain various exit commands and in some cases
+completion commands (@pxref{Completion}).
+
+@itemize @bullet
+@item
+@code{minibuffer-local-map} is for ordinary input (no completion).
+
+@item
+@code{minibuffer-local-ns-map} is similar, except that @key{SPC} exits
+just like @key{RET}.  This is used mainly for Mocklisp compatibility.
+
+@item
+@code{minibuffer-local-completion-map} is for permissive completion.
+
+@item
+@code{minibuffer-local-must-match-map} is for strict completion and
+for cautious completion.
+@end itemize
+
+@node Text from Minibuffer
+@section Reading Text Strings with the Minibuffer
+
+  Most often, the minibuffer is used to read text as a string.  It can
+also be used to read a Lisp object in textual form.  The most basic
+primitive for minibuffer input is @code{read-from-minibuffer}; it can do
+either one.
+
+  In most cases, you should not call minibuffer input functions in the
+middle of a Lisp function.  Instead, do all minibuffer input as part of
+reading the arguments for a command, in the @code{interactive} spec.
+@xref{Defining Commands}.
+
+@defun read-from-minibuffer prompt-string &optional initial-contents keymap read hist
+This function is the most general way to get input through the
+minibuffer.  By default, it accepts arbitrary text and returns it as a
+string; however, if @var{read} is non-@code{nil}, then it uses
+@code{read} to convert the text into a Lisp object (@pxref{Input
+Functions}).
+
+The first thing this function does is to activate a minibuffer and 
+display it with @var{prompt-string} as the prompt.  This value must be a
+string.
+
+Then, if @var{initial-contents} is a string, @code{read-from-minibuffer}
+inserts it into the minibuffer, leaving point at the end.  The
+minibuffer appears with this text as its contents.
+
+@c Emacs 19 feature
+The value of @var{initial-contents} may also be a cons cell of the form
+@code{(@var{string} . @var{position})}.  This means to insert
+@var{string} in the minibuffer but put point @var{position} characters
+from the beginning, rather than at the end.
+
+If @var{keymap} is non-@code{nil}, that keymap is the local keymap to
+use in the minibuffer.  If @var{keymap} is omitted or @code{nil}, the
+value of @code{minibuffer-local-map} is used as the keymap.  Specifying
+a keymap is the most important way to customize the minibuffer for
+various applications such as completion.
+
+The argument @var{hist} specifies which history list variable to use
+for saving the input and for history commands used in the minibuffer.
+It defaults to @code{minibuffer-history}.  @xref{Minibuffer History}.
+
+When the user types a command to exit the minibuffer,
+@code{read-from-minibuffer} uses the text in the minibuffer to produce
+its return value.  Normally it simply makes a string containing that
+text.  However, if @var{read} is non-@code{nil},
+@code{read-from-minibuffer} reads the text and returns the resulting
+Lisp object, unevaluated.  (@xref{Input Functions}, for information
+about reading.)
+@end defun
+
+@defun read-string prompt &optional initial
+This function reads a string from the minibuffer and returns it.  The
+arguments @var{prompt} and @var{initial} are used as in
+@code{read-from-minibuffer}.  The keymap used is
+@code{minibuffer-local-map}.
+
+This is a simplified interface to the
+@code{read-from-minibuffer} function:
+
+@smallexample
+@group
+(read-string @var{prompt} @var{initial})
+@equiv{}
+(read-from-minibuffer @var{prompt} @var{initial} nil nil nil)
+@end group
+@end smallexample
+@end defun
+
+@defvar minibuffer-local-map
+This is the default local keymap for reading from the minibuffer.  By
+default, it makes the following bindings:
+
+@table @asis
+@item @key{LFD}
+@code{exit-minibuffer}
+
+@item @key{RET}
+@code{exit-minibuffer}
+
+@item @kbd{C-g}
+@code{abort-recursive-edit}
+
+@item @kbd{M-n}
+@code{next-history-element}
+
+@item @kbd{M-p}
+@code{previous-history-element}
+
+@item @kbd{M-r}
+@code{next-matching-history-element}
+
+@item @kbd{M-s}
+@code{previous-matching-history-element}
+@end table
+@end defvar
+
+@c In version 18, initial is required
+@c Emacs 19 feature
+@defun read-no-blanks-input prompt &optional initial
+This function reads a string from the minibuffer, but does not allow
+whitespace characters as part of the input: instead, those characters
+terminate the input.  The arguments @var{prompt} and @var{initial} are
+used as in @code{read-from-minibuffer}.
+
+This is a simplified interface to the @code{read-from-minibuffer}
+function, and passes the value of the @code{minibuffer-local-ns-map}
+keymap as the @var{keymap} argument for that function.  Since the keymap
+@code{minibuffer-local-ns-map} does not rebind @kbd{C-q}, it @emph{is}
+possible to put a space into the string, by quoting it.
+
+@smallexample
+@group
+(read-no-blanks-input @var{prompt} @var{initial})
+@equiv{}
+(read-from-minibuffer @var{prompt} @var{initial} minibuffer-local-ns-map)
+@end group
+@end smallexample
+@end defun
+
+@defvar minibuffer-local-ns-map
+This built-in variable is the keymap used as the minibuffer local keymap
+in the function @code{read-no-blanks-input}.  By default, it makes the
+following bindings, in addition to those of @code{minibuffer-local-map}:
+
+@table @asis
+@item @key{SPC}
+@cindex @key{SPC} in minibuffer
+@code{exit-minibuffer}
+
+@item @key{TAB}
+@cindex @key{TAB} in minibuffer
+@code{exit-minibuffer}
+
+@item @kbd{?}
+@cindex @kbd{?} in minibuffer
+@code{self-insert-and-exit}
+@end table
+@end defvar
+
+@node Object from Minibuffer
+@section Reading Lisp Objects with the Minibuffer
+
+  This section describes functions for reading Lisp objects with the
+minibuffer.
+
+@defun read-minibuffer prompt &optional initial
+This function reads a Lisp object in the minibuffer and returns it,
+without evaluating it.  The arguments @var{prompt} and @var{initial} are
+used as in @code{read-from-minibuffer}.
+
+This is a simplified interface to the
+@code{read-from-minibuffer} function:
+
+@smallexample
+@group
+(read-minibuffer @var{prompt} @var{initial})
+@equiv{}
+(read-from-minibuffer @var{prompt} @var{initial} nil t)
+@end group
+@end smallexample
+
+Here is an example in which we supply the string @code{"(testing)"} as
+initial input:
+
+@smallexample
+@group
+(read-minibuffer
+ "Enter an expression: " (format "%s" '(testing)))
+
+;; @r{Here is how the minibuffer is displayed:}
+@end group
+
+@group
+---------- Buffer: Minibuffer ----------
+Enter an expression: (testing)@point{}
+---------- Buffer: Minibuffer ----------
+@end group
+@end smallexample
+
+@noindent
+The user can type @key{RET} immediately to use the initial input as a
+default, or can edit the input.
+@end defun
+
+@defun eval-minibuffer prompt &optional initial
+This function reads a Lisp expression in the minibuffer, evaluates it,
+then returns the result.  The arguments @var{prompt} and @var{initial}
+are used as in @code{read-from-minibuffer}.
+
+This function simply evaluates the result of a call to
+@code{read-minibuffer}:
+
+@smallexample
+@group
+(eval-minibuffer @var{prompt} @var{initial})
+@equiv{}
+(eval (read-minibuffer @var{prompt} @var{initial}))
+@end group
+@end smallexample
+@end defun
+
+@defun edit-and-eval-command prompt form
+This function reads a Lisp expression in the minibuffer, and then
+evaluates it.  The difference between this command and
+@code{eval-minibuffer} is that here the initial @var{form} is not
+optional and it is treated as a Lisp object to be converted to printed
+representation rather than as a string of text.  It is printed with
+@code{prin1}, so if it is a string, double-quote characters (@samp{"})
+appear in the initial text.  @xref{Output Functions}.
+
+The first thing @code{edit-and-eval-command} does is to activate the
+minibuffer with @var{prompt} as the prompt.  Then it inserts the printed
+representation of @var{form} in the minibuffer, and lets the user edit.
+When the user exits the minibuffer, the edited text is read with
+@code{read} and then evaluated.  The resulting value becomes the value
+of @code{edit-and-eval-command}.
+
+In the following example, we offer the user an expression with initial
+text which is a valid form already:
+
+@smallexample
+@group
+(edit-and-eval-command "Please edit: " '(forward-word 1))
+
+;; @r{After evaluation of the preceding expression,} 
+;;   @r{the following appears in the minibuffer:}
+@end group
+
+@group
+---------- Buffer: Minibuffer ----------
+Please edit: (forward-word 1)@point{}
+---------- Buffer: Minibuffer ----------
+@end group
+@end smallexample
+
+@noindent
+Typing @key{RET} right away would exit the minibuffer and evaluate the
+expression, thus moving point forward one word.
+@code{edit-and-eval-command} returns @code{nil} in this example.
+@end defun
+
+@node Minibuffer History
+@section Minibuffer History
+@cindex minibuffer history
+@cindex history list
+
+A @dfn{minibuffer history list} records previous minibuffer inputs so
+the user can reuse them conveniently.  A history list is actually a
+symbol, not a list; it is a variable whose value is a list of strings
+(previous inputs), most recent first.
+
+There are many separate history lists, used for different kinds of
+inputs.  It's the Lisp programmer's job to specify the right history
+list for each use of the minibuffer.
+
+The basic minibuffer input functions @code{read-from-minibuffer} and
+@code{completing-read} both accept an optional argument named @var{hist}
+which is how you specify the history list.  Here are the possible
+values:
+
+@table @asis
+@item @var{variable}
+Use @var{variable} (a symbol) as the history list.
+
+@item (@var{variable} . @var{startpos})
+Use @var{variable} (a symbol) as the history list, and assume that the
+initial history position is @var{startpos} (an integer, counting from
+zero which specifies the most recent element of the history).
+
+If you specify @var{startpos}, then you should also specify that element
+of the history as the initial minibuffer contents, for consistency.
+@end table
+
+If you don't specify @var{hist}, then the default history list
+@code{minibuffer-history} is used.  For other standard history lists,
+see below.  You can also create your own history list variable; just
+initialize it to @code{nil} before the first use.
+
+Both @code{read-from-minibuffer} and @code{completing-read} add new
+elements to the history list automatically, and provide commands to
+allow the user to reuse items on the list.  The only thing your program
+needs to do to use a history list is to initialize it and to pass its
+name to the input functions when you wish.  But it is safe to modify the
+list by hand when the minibuffer input functions are not using it.
+
+@defvar minibuffer-history
+The default history list for minibuffer history input.
+@end defvar
+
+@defvar query-replace-history
+A history list for arguments to @code{query-replace} (and similar
+arguments to other commands).
+@end defvar
+
+@defvar file-name-history
+A history list for file name arguments.
+@end defvar
+
+@defvar regexp-history
+A history list for regular expression arguments.
+@end defvar
+
+@defvar extended-command-history
+A history list for arguments that are names of extended commands.
+@end defvar
+
+@defvar shell-command-history
+A history list for arguments that are shell commands.
+@end defvar
+
+@defvar read-expression-history
+A history list for arguments that are Lisp expressions to evaluate.
+@end defvar
+
+@node Completion
+@section Completion
+@cindex completion
+
+  @dfn{Completion} is a feature that fills in the rest of a name
+starting from an abbreviation for it.  Completion works by comparing the
+user's input against a list of valid names and determining how much of
+the name is determined uniquely by what the user has typed.  For
+example, when you type @kbd{C-x b} (@code{switch-to-buffer}) and then
+type the first few letters of the name of the buffer to which you wish
+to switch, and then type @key{TAB} (@code{minibuffer-complete}), Emacs
+extends the name as far as it can.
+
+  Standard XEmacs commands offer completion for names of symbols, files,
+buffers, and processes; with the functions in this section, you can
+implement completion for other kinds of names.
+
+  The @code{try-completion} function is the basic primitive for
+completion: it returns the longest determined completion of a given
+initial string, with a given set of strings to match against.
+
+  The function @code{completing-read} provides a higher-level interface
+for completion.  A call to @code{completing-read} specifies how to
+determine the list of valid names.  The function then activates the
+minibuffer with a local keymap that binds a few keys to commands useful
+for completion.  Other functions provide convenient simple interfaces
+for reading certain kinds of names with completion.
+
+@menu
+* Basic Completion::       Low-level functions for completing strings.
+                             (These are too low level to use the minibuffer.)
+* Minibuffer Completion::  Invoking the minibuffer with completion.
+* Completion Commands::    Minibuffer commands that do completion.
+* High-Level Completion::  Convenient special cases of completion
+                             (reading buffer name, file name, etc.)
+* Reading File Names::     Using completion to read file names.
+* Programmed Completion::  Finding the completions for a given file name.
+@end menu
+
+@node Basic Completion
+@subsection Basic Completion Functions
+
+  The two functions @code{try-completion} and @code{all-completions}
+have nothing in themselves to do with minibuffers.  We describe them in
+this chapter so as to keep them near the higher-level completion
+features that do use the minibuffer.
+
+@defun try-completion string collection &optional predicate
+This function returns the longest common substring of all possible
+completions of @var{string} in @var{collection}.  The value of
+@var{collection} must be an alist, an obarray, or a function that
+implements a virtual set of strings (see below).
+
+Completion compares @var{string} against each of the permissible
+completions specified by @var{collection}; if the beginning of the
+permissible completion equals @var{string}, it matches.  If no permissible
+completions match, @code{try-completion} returns @code{nil}.  If only
+one permissible completion matches, and the match is exact, then
+@code{try-completion} returns @code{t}.  Otherwise, the value is the
+longest initial sequence common to all the permissible completions that
+match.
+
+If @var{collection} is an alist (@pxref{Association Lists}), the
+@sc{car}s of the alist elements form the set of permissible completions.
+
+@cindex obarray in completion
+If @var{collection} is an obarray (@pxref{Creating Symbols}), the names
+of all symbols in the obarray form the set of permissible completions.  The
+global variable @code{obarray} holds an obarray containing the names of
+all interned Lisp symbols.
+
+Note that the only valid way to make a new obarray is to create it
+empty and then add symbols to it one by one using @code{intern}.
+Also, you cannot intern a given symbol in more than one obarray.
+
+If the argument @var{predicate} is non-@code{nil}, then it must be a
+function of one argument.  It is used to test each possible match, and
+the match is accepted only if @var{predicate} returns non-@code{nil}.
+The argument given to @var{predicate} is either a cons cell from the alist
+(the @sc{car} of which is a string) or else it is a symbol (@emph{not} a
+symbol name) from the obarray.
+
+You can also use a symbol that is a function as @var{collection}.  Then
+the function is solely responsible for performing completion;
+@code{try-completion} returns whatever this function returns.  The
+function is called with three arguments: @var{string}, @var{predicate}
+and @code{nil}.  (The reason for the third argument is so that the same
+function can be used in @code{all-completions} and do the appropriate
+thing in either case.)  @xref{Programmed Completion}.
+
+In the first of the following examples, the string @samp{foo} is
+matched by three of the alist @sc{car}s.  All of the matches begin with
+the characters @samp{fooba}, so that is the result.  In the second
+example, there is only one possible match, and it is exact, so the value
+is @code{t}.
+
+@smallexample
+@group
+(try-completion 
+ "foo"
+ '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)))
+     @result{} "fooba"
+@end group
+
+@group
+(try-completion "foo" '(("barfoo" 2) ("foo" 3)))
+     @result{} t
+@end group
+@end smallexample
+
+In the following example, numerous symbols begin with the characters
+@samp{forw}, and all of them begin with the word @samp{forward}.  In
+most of the symbols, this is followed with a @samp{-}, but not in all,
+so no more than @samp{forward} can be completed.
+
+@smallexample
+@group
+(try-completion "forw" obarray)
+     @result{} "forward"
+@end group
+@end smallexample
+
+Finally, in the following example, only two of the three possible
+matches pass the predicate @code{test} (the string @samp{foobaz} is
+too short).  Both of those begin with the string @samp{foobar}.
+
+@smallexample
+@group
+(defun test (s) 
+  (> (length (car s)) 6))
+     @result{} test
+@end group
+@group
+(try-completion 
+ "foo"
+ '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)) 
+ 'test)
+     @result{} "foobar"
+@end group
+@end smallexample
+@end defun
+
+@defun all-completions string collection &optional predicate nospace
+This function returns a list of all possible completions of
+@var{string}.  The parameters to this function are the same as to
+@code{try-completion}.
+
+If @var{collection} is a function, it is called with three arguments:
+@var{string}, @var{predicate} and @code{t}; then @code{all-completions}
+returns whatever the function returns.  @xref{Programmed Completion}.
+
+If @var{nospace} is non-@code{nil}, completions that start with a space
+are ignored unless @var{string} also starts with a space.
+
+Here is an example, using the function @code{test} shown in the
+example for @code{try-completion}:
+
+@smallexample
+@group
+(defun test (s) 
+  (> (length (car s)) 6))
+     @result{} test
+@end group
+
+@group
+(all-completions  
+ "foo"
+ '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))
+ 'test)
+     @result{} ("foobar1" "foobar2")
+@end group
+@end smallexample
+@end defun
+
+@defvar completion-ignore-case
+If the value of this variable is 
+non-@code{nil}, XEmacs does not consider case significant in completion.
+@end defvar
+
+@node Minibuffer Completion
+@subsection Completion and the Minibuffer
+
+  This section describes the basic interface for reading from the
+minibuffer with completion.
+
+@defun completing-read prompt collection &optional predicate require-match initial hist
+This function reads a string in the minibuffer, assisting the user by
+providing completion.  It activates the minibuffer with prompt
+@var{prompt}, which must be a string.  If @var{initial} is
+non-@code{nil}, @code{completing-read} inserts it into the minibuffer as
+part of the input.  Then it allows the user to edit the input, providing
+several commands to attempt completion.
+
+The actual completion is done by passing @var{collection} and
+@var{predicate} to the function @code{try-completion}.  This happens in
+certain commands bound in the local keymaps used for completion.
+
+If @var{require-match} is @code{t}, the usual minibuffer exit commands
+won't exit unless the input completes to an element of @var{collection}.
+If @var{require-match} is neither @code{nil} nor @code{t}, then the exit
+commands won't exit unless the input typed is itself an element of
+@var{collection}.  If @var{require-match} is @code{nil}, the exit
+commands work regardless of the input in the minibuffer.
+
+The user can exit with null input by typing @key{RET} with an empty
+minibuffer.  Then @code{completing-read} returns @code{nil}.  This is
+how the user requests whatever default the command uses for the value
+being read.  The user can return using @key{RET} in this way regardless
+of the value of @var{require-match}.
+
+The function @code{completing-read} works by calling
+@code{read-minibuffer}.  It uses @code{minibuffer-local-completion-map}
+as the keymap if @var{require-match} is @code{nil}, and uses
+@code{minibuffer-local-must-match-map} if @var{require-match} is
+non-@code{nil}.  @xref{Completion Commands}.
+
+The argument @var{hist} specifies which history list variable to use for
+saving the input and for minibuffer history commands.  It defaults to
+@code{minibuffer-history}.  @xref{Minibuffer History}.
+
+Completion ignores case when comparing the input against the possible
+matches, if the built-in variable @code{completion-ignore-case} is
+non-@code{nil}.  @xref{Basic Completion}.
+
+Here's an example of using @code{completing-read}:
+
+@smallexample
+@group
+(completing-read
+ "Complete a foo: "
+ '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))
+ nil t "fo")
+@end group
+
+@group
+;; @r{After evaluation of the preceding expression,} 
+;;   @r{the following appears in the minibuffer:}
+
+---------- Buffer: Minibuffer ----------
+Complete a foo: fo@point{}
+---------- Buffer: Minibuffer ----------
+@end group
+@end smallexample
+
+@noindent
+If the user then types @kbd{@key{DEL} @key{DEL} b @key{RET}},
+@code{completing-read} returns @code{barfoo}.
+
+The @code{completing-read} function binds three variables to pass
+information to the commands that actually do completion.  These
+variables are @code{minibuffer-completion-table},
+@code{minibuffer-completion-predicate} and
+@code{minibuffer-completion-confirm}.  For more information about them,
+see @ref{Completion Commands}.
+@end defun
+
+@node Completion Commands
+@subsection Minibuffer Commands That Do Completion
+
+  This section describes the keymaps, commands and user options used in
+the minibuffer to do completion.
+
+@defvar minibuffer-local-completion-map
+@code{completing-read} uses this value as the local keymap when an
+exact match of one of the completions is not required.  By default, this
+keymap makes the following bindings:
+
+@table @asis
+@item @kbd{?}
+@code{minibuffer-completion-help}
+
+@item @key{SPC}
+@code{minibuffer-complete-word}
+
+@item @key{TAB}
+@code{minibuffer-complete}
+@end table
+
+@noindent
+with other characters bound as in @code{minibuffer-local-map}
+(@pxref{Text from Minibuffer}).
+@end defvar
+
+@defvar minibuffer-local-must-match-map
+@code{completing-read} uses this value as the local keymap when an
+exact match of one of the completions is required.  Therefore, no keys
+are bound to @code{exit-minibuffer}, the command that exits the
+minibuffer unconditionally.  By default, this keymap makes the following
+bindings:
+
+@table @asis
+@item @kbd{?}
+@code{minibuffer-completion-help}
+
+@item @key{SPC}
+@code{minibuffer-complete-word}
+
+@item @key{TAB}
+@code{minibuffer-complete}
+
+@item @key{LFD}
+@code{minibuffer-complete-and-exit}
+
+@item @key{RET}
+@code{minibuffer-complete-and-exit}
+@end table
+
+@noindent
+with other characters bound as in @code{minibuffer-local-map}.
+@end defvar
+
+@defvar minibuffer-completion-table
+The value of this variable is the alist or obarray used for completion
+in the minibuffer.  This is the global variable that contains what
+@code{completing-read} passes to @code{try-completion}.  It is used by
+minibuffer completion commands such as @code{minibuffer-complete-word}.
+@end defvar
+
+@defvar minibuffer-completion-predicate
+This variable's value is the predicate that @code{completing-read}
+passes to @code{try-completion}.  The variable is also used by the other
+minibuffer completion functions.
+@end defvar
+
+@deffn Command minibuffer-complete-word
+This function completes the minibuffer contents by at most a single
+word.  Even if the minibuffer contents have only one completion,
+@code{minibuffer-complete-word} does not add any characters beyond the
+first character that is not a word constituent.  @xref{Syntax Tables}.
+@end deffn
+
+@deffn Command minibuffer-complete
+This function completes the minibuffer contents as far as possible.
+@end deffn
+
+@deffn Command minibuffer-complete-and-exit
+This function completes the minibuffer contents, and exits if
+confirmation is not required, i.e., if
+@code{minibuffer-completion-confirm} is non-@code{nil}.  If confirmation
+@emph{is} required, it is given by repeating this command
+immediately---the command is programmed to work without confirmation
+when run twice in succession.
+@end deffn
+
+@defvar minibuffer-completion-confirm
+When the value of this variable is non-@code{nil}, XEmacs asks for
+confirmation of a completion before exiting the minibuffer.  The
+function @code{minibuffer-complete-and-exit} checks the value of this
+variable before it exits.
+@end defvar
+
+@deffn Command minibuffer-completion-help
+This function creates a list of the possible completions of the
+current minibuffer contents.  It works by calling @code{all-completions}
+using the value of the variable @code{minibuffer-completion-table} as
+the @var{collection} argument, and the value of
+@code{minibuffer-completion-predicate} as the @var{predicate} argument.
+The list of completions is displayed as text in a buffer named
+@samp{*Completions*}.
+@end deffn
+
+@defun display-completion-list completions
+This function displays @var{completions} to the stream in
+@code{standard-output}, usually a buffer.  (@xref{Read and Print}, for more
+information about streams.)  The argument @var{completions} is normally
+a list of completions just returned by @code{all-completions}, but it
+does not have to be.  Each element may be a symbol or a string, either
+of which is simply printed, or a list of two strings, which is printed
+as if the strings were concatenated.
+
+This function is called by @code{minibuffer-completion-help}.  The
+most common way to use it is together with
+@code{with-output-to-temp-buffer}, like this:
+
+@example
+(with-output-to-temp-buffer "*Completions*"
+  (display-completion-list
+    (all-completions (buffer-string) my-alist)))
+@end example
+@end defun
+
+@defopt completion-auto-help
+If this variable is non-@code{nil}, the completion commands
+automatically display a list of possible completions whenever nothing
+can be completed because the next character is not uniquely determined.
+@end defopt
+
+@node High-Level Completion
+@subsection High-Level Completion  Functions
+
+  This section describes the higher-level convenient functions for
+reading certain sorts of names with completion.
+
+  In most cases, you should not call these functions in the middle of a
+Lisp function.  When possible, do all minibuffer input as part of
+reading the arguments for a command, in the @code{interactive} spec.
+@xref{Defining Commands}.
+
+@defun read-buffer prompt &optional default existing
+This function reads the name of a buffer and returns it as a string.
+The argument @var{default} is the default name to use, the value to
+return if the user exits with an empty minibuffer.  If non-@code{nil},
+it should be a string or a buffer.  It is mentioned in the prompt, but
+is not inserted in the minibuffer as initial input.
+
+If @var{existing} is non-@code{nil}, then the name specified must be
+that of an existing buffer.  The usual commands to exit the minibuffer
+do not exit if the text is not valid, and @key{RET} does completion to
+attempt to find a valid name.  (However, @var{default} is not checked
+for validity; it is returned, whatever it is, if the user exits with the
+minibuffer empty.)
+
+In the following example, the user enters @samp{minibuffer.t}, and
+then types @key{RET}.  The argument @var{existing} is @code{t}, and the
+only buffer name starting with the given input is
+@samp{minibuffer.texi}, so that name is the value.
+
+@example
+(read-buffer "Buffer name? " "foo" t)
+@group
+;; @r{After evaluation of the preceding expression,} 
+;;   @r{the following prompt appears,}
+;;   @r{with an empty minibuffer:}
+@end group
+
+@group
+---------- Buffer: Minibuffer ----------
+Buffer name? (default foo) @point{}
+---------- Buffer: Minibuffer ----------
+@end group
+
+@group
+;; @r{The user types @kbd{minibuffer.t @key{RET}}.}
+     @result{} "minibuffer.texi"
+@end group
+@end example
+@end defun
+
+@defun read-command prompt
+This function reads the name of a command and returns it as a Lisp
+symbol.  The argument @var{prompt} is used as in
+@code{read-from-minibuffer}.  Recall that a command is anything for
+which @code{commandp} returns @code{t}, and a command name is a symbol
+for which @code{commandp} returns @code{t}.  @xref{Interactive Call}.
+
+@example
+(read-command "Command name? ")
+
+@group
+;; @r{After evaluation of the preceding expression,} 
+;;   @r{the following prompt appears with an empty minibuffer:}
+@end group
+
+@group
+---------- Buffer: Minibuffer ---------- 
+Command name?  
+---------- Buffer: Minibuffer ----------
+@end group
+@end example
+
+@noindent
+If the user types @kbd{forward-c @key{RET}}, then this function returns
+@code{forward-char}.
+
+The @code{read-command} function is a simplified interface to the
+function @code{completing-read}.  It uses the variable @code{obarray} so
+as to complete in the set of extant Lisp symbols, and it uses the
+@code{commandp} predicate so as to accept only command names:
+
+@cindex @code{commandp} example
+@example
+@group
+(read-command @var{prompt})
+@equiv{}
+(intern (completing-read @var{prompt} obarray 
+                         'commandp t nil))
+@end group
+@end example
+@end defun
+
+@defun read-variable prompt
+This function reads the name of a user variable and returns it as a
+symbol.
+
+@example
+@group
+(read-variable "Variable name? ")
+
+;; @r{After evaluation of the preceding expression,} 
+;;   @r{the following prompt appears,} 
+;;   @r{with an empty minibuffer:}
+@end group
+
+@group
+---------- Buffer: Minibuffer ----------
+Variable name? @point{}
+---------- Buffer: Minibuffer ----------
+@end group
+@end example
+
+@noindent
+If the user then types @kbd{fill-p @key{RET}}, @code{read-variable}
+returns @code{fill-prefix}.
+
+This function is similar to @code{read-command}, but uses the
+predicate @code{user-variable-p} instead of @code{commandp}:
+
+@cindex @code{user-variable-p} example
+@example
+@group
+(read-variable @var{prompt})
+@equiv{}
+(intern
+ (completing-read @var{prompt} obarray
+                  'user-variable-p t nil))
+@end group
+@end example
+@end defun
+
+@node Reading File Names
+@subsection Reading File Names
+
+  Here is another high-level completion function, designed for reading a
+file name.  It provides special features including automatic insertion
+of the default directory.
+
+@defun read-file-name prompt &optional directory default existing initial
+This function reads a file name in the minibuffer, prompting with
+@var{prompt} and providing completion.  If @var{default} is
+non-@code{nil}, then the function returns @var{default} if the user just
+types @key{RET}.  @var{default} is not checked for validity; it is
+returned, whatever it is, if the user exits with the minibuffer empty.
+
+If @var{existing} is non-@code{nil}, then the user must specify the name
+of an existing file; @key{RET} performs completion to make the name
+valid if possible, and then refuses to exit if it is not valid.  If the
+value of @var{existing} is neither @code{nil} nor @code{t}, then
+@key{RET} also requires confirmation after completion.  If
+@var{existing} is @code{nil}, then the name of a nonexistent file is
+acceptable.
+
+The argument @var{directory} specifies the directory to use for
+completion of relative file names.  If @code{insert-default-directory}
+is non-@code{nil}, @var{directory} is also inserted in the minibuffer as
+initial input.  It defaults to the current buffer's value of
+@code{default-directory}.
+
+@c Emacs 19 feature
+If you specify @var{initial}, that is an initial file name to insert in
+the buffer (after with @var{directory}, if that is inserted).  In this
+case, point goes at the beginning of @var{initial}.  The default for
+@var{initial} is @code{nil}---don't insert any file name.  To see what
+@var{initial} does, try the command @kbd{C-x C-v}.
+
+Here is an example: 
+
+@example
+@group
+(read-file-name "The file is ")
+
+;; @r{After evaluation of the preceding expression,} 
+;;   @r{the following appears in the minibuffer:}
+@end group
+
+@group
+---------- Buffer: Minibuffer ----------
+The file is /gp/gnu/elisp/@point{}
+---------- Buffer: Minibuffer ----------
+@end group
+@end example
+
+@noindent
+Typing @kbd{manual @key{TAB}} results in the following:
+
+@example
+@group
+---------- Buffer: Minibuffer ----------
+The file is /gp/gnu/elisp/manual.texi@point{}
+---------- Buffer: Minibuffer ----------
+@end group
+@end example
+
+@c Wordy to avoid overfull hbox in smallbook mode.
+@noindent
+If the user types @key{RET}, @code{read-file-name} returns the file name
+as the string @code{"/gp/gnu/elisp/manual.texi"}.
+@end defun
+
+@defopt insert-default-directory
+This variable is used by @code{read-file-name}.  Its value controls
+whether @code{read-file-name} starts by placing the name of the default
+directory in the minibuffer, plus the initial file name if any.  If the
+value of this variable is @code{nil}, then @code{read-file-name} does
+not place any initial input in the minibuffer (unless you specify
+initial input with the @var{initial} argument).  In that case, the
+default directory is still used for completion of relative file names,
+but is not displayed.
+
+For example:
+
+@example
+@group
+;; @r{Here the minibuffer starts out with the default directory.}
+(let ((insert-default-directory t))
+  (read-file-name "The file is "))
+@end group
+
+@group
+---------- Buffer: Minibuffer ----------
+The file is ~lewis/manual/@point{}
+---------- Buffer: Minibuffer ----------
+@end group
+
+@group
+;; @r{Here the minibuffer is empty and only the prompt}
+;;   @r{appears on its line.}
+(let ((insert-default-directory nil))
+  (read-file-name "The file is "))
+@end group
+
+@group
+---------- Buffer: Minibuffer ----------
+The file is @point{}
+---------- Buffer: Minibuffer ----------
+@end group
+@end example
+@end defopt
+
+@node Programmed Completion
+@subsection Programmed Completion
+@cindex programmed completion
+
+  Sometimes it is not possible to create an alist or an obarray
+containing all the intended possible completions.  In such a case, you
+can supply your own function to compute the completion of a given string.
+This is called @dfn{programmed completion}.
+
+  To use this feature, pass a symbol with a function definition as the
+@var{collection} argument to @code{completing-read}.  The function
+@code{completing-read} arranges to pass your completion function along
+to @code{try-completion} and @code{all-completions}, which will then let
+your function do all the work.
+
+  The completion function should accept three arguments:
+
+@itemize @bullet
+@item
+The string to be completed.
+
+@item
+The predicate function to filter possible matches, or @code{nil} if
+none.  Your function should call the predicate for each possible match,
+and ignore the possible match if the predicate returns @code{nil}.
+
+@item
+A flag specifying the type of operation.
+@end itemize
+
+  There are three flag values for three operations:
+
+@itemize @bullet
+@item
+@code{nil} specifies @code{try-completion}.  The completion function
+should return the completion of the specified string, or @code{t} if the
+string is an exact match already, or @code{nil} if the string matches no
+possibility.
+
+@item
+@code{t} specifies @code{all-completions}.  The completion function
+should return a list of all possible completions of the specified
+string.
+
+@item
+@code{lambda} specifies a test for an exact match.  The completion
+function should return @code{t} if the specified string is an exact
+match for some possibility; @code{nil} otherwise.
+@end itemize
+
+  It would be consistent and clean for completion functions to allow
+lambda expressions (lists that are functions) as well as function
+symbols as @var{collection}, but this is impossible.  Lists as
+completion tables are already assigned another meaning---as alists.  It
+would be unreliable to fail to handle an alist normally because it is
+also a possible function.  So you must arrange for any function you wish
+to use for completion to be encapsulated in a symbol.
+
+  Emacs uses programmed completion when completing file names.
+@xref{File Name Completion}.
+
+@node Yes-or-No Queries
+@section Yes-or-No Queries
+@cindex asking the user questions
+@cindex querying the user
+@cindex yes-or-no questions
+
+  This section describes functions used to ask the user a yes-or-no
+question.  The function @code{y-or-n-p} can be answered with a single
+character; it is useful for questions where an inadvertent wrong answer
+will not have serious consequences.  @code{yes-or-no-p} is suitable for
+more momentous questions, since it requires three or four characters to
+answer.  Variations of these functions can be used to ask a yes-or-no
+question using a dialog box, or optionally using one.
+
+   If either of these functions is called in a command that was invoked
+using the mouse, then it uses a dialog box or pop-up menu to ask the
+question.  Otherwise, it uses keyboard input.
+
+  Strictly speaking, @code{yes-or-no-p} uses the minibuffer and
+@code{y-or-n-p} does not; but it seems best to describe them together.
+
+@defun y-or-n-p prompt
+This function asks the user a question, expecting input in the echo
+area.  It returns @code{t} if the user types @kbd{y}, @code{nil} if the
+user types @kbd{n}.  This function also accepts @key{SPC} to mean yes
+and @key{DEL} to mean no.  It accepts @kbd{C-]} to mean ``quit'', like
+@kbd{C-g}, because the question might look like a minibuffer and for
+that reason the user might try to use @kbd{C-]} to get out.  The answer
+is a single character, with no @key{RET} needed to terminate it.  Upper
+and lower case are equivalent.
+
+``Asking the question'' means printing @var{prompt} in the echo area,
+followed by the string @w{@samp{(y or n) }}.  If the input is not one of
+the expected answers (@kbd{y}, @kbd{n}, @kbd{@key{SPC}},
+@kbd{@key{DEL}}, or something that quits), the function responds
+@samp{Please answer y or n.}, and repeats the request.
+
+This function does not actually use the minibuffer, since it does not
+allow editing of the answer.  It actually uses the echo area (@pxref{The
+Echo Area}), which uses the same screen space as the minibuffer.  The
+cursor moves to the echo area while the question is being asked.
+
+The answers and their meanings, even @samp{y} and @samp{n}, are not
+hardwired.  The keymap @code{query-replace-map} specifies them.
+@xref{Search and Replace}.
+
+In the following example, the user first types @kbd{q}, which is
+invalid.  At the next prompt the user types @kbd{y}.
+
+@smallexample
+@group
+(y-or-n-p "Do you need a lift? ")
+
+;; @r{After evaluation of the preceding expression,} 
+;;   @r{the following prompt appears in the echo area:}
+@end group
+
+@group
+---------- Echo area ----------
+Do you need a lift? (y or n) 
+---------- Echo area ----------
+@end group
+
+;; @r{If the user then types @kbd{q}, the following appears:}
+
+@group
+---------- Echo area ----------
+Please answer y or n.  Do you need a lift? (y or n) 
+---------- Echo area ----------
+@end group
+
+;; @r{When the user types a valid answer,}
+;;   @r{it is displayed after the question:}
+
+@group
+---------- Echo area ----------
+Do you need a lift? (y or n) y
+---------- Echo area ----------
+@end group
+@end smallexample
+
+@noindent
+We show successive lines of echo area messages, but only one actually
+appears on the screen at a time.
+@end defun
+
+@defun yes-or-no-p prompt
+This function asks the user a question, expecting input in the
+minibuffer.  It returns @code{t} if the user enters @samp{yes},
+@code{nil} if the user types @samp{no}.  The user must type @key{RET} to
+finalize the response.  Upper and lower case are equivalent.
+
+@code{yes-or-no-p} starts by displaying @var{prompt} in the echo area,
+followed by @w{@samp{(yes or no) }}.  The user must type one of the
+expected responses; otherwise, the function responds @samp{Please answer
+yes or no.}, waits about two seconds and repeats the request.
+
+@code{yes-or-no-p} requires more work from the user than
+@code{y-or-n-p} and is appropriate for more crucial decisions.
+
+Here is an example:
+
+@smallexample
+@group
+(yes-or-no-p "Do you really want to remove everything? ")
+
+;; @r{After evaluation of the preceding expression,} 
+;;   @r{the following prompt appears,} 
+;;   @r{with an empty minibuffer:}
+@end group
+
+@group
+---------- Buffer: minibuffer ----------
+Do you really want to remove everything? (yes or no) 
+---------- Buffer: minibuffer ----------
+@end group
+@end smallexample
+
+@noindent
+If the user first types @kbd{y @key{RET}}, which is invalid because this
+function demands the entire word @samp{yes}, it responds by displaying
+these prompts, with a brief pause between them:
+
+@smallexample
+@group
+---------- Buffer: minibuffer ----------
+Please answer yes or no.
+Do you really want to remove everything? (yes or no)
+---------- Buffer: minibuffer ----------
+@end group
+@end smallexample
+@end defun
+
+@c The rest is XEmacs stuff
+@defun yes-or-no-p-dialog-box prompt
+This function asks the user a ``y or n'' question with a popup dialog
+box.  It returns @code{t} if the answer is ``yes''.  @var{prompt} is the
+string to display to ask the question.
+@end defun
+
+The following functions ask a question either in the minibuffer or a
+dialog box, depending on whether the last user event (which presumably
+invoked this command) was a keyboard or mouse event.  When XEmacs is
+running on a window system, the functions @code{y-or-n-p} and
+@code{yes-or-no-p} are replaced with the following functions, so that
+menu items bring up dialog boxes instead of minibuffer questions.
+
+@defun y-or-n-p-maybe-dialog-box prompt
+This function asks user a ``y or n'' question, using either a dialog box
+or the minibuffer, as appropriate.
+@end defun
+
+@defun yes-or-no-p-maybe-dialog-box prompt
+This function asks user a ``yes or no'' question, using either a dialog
+box or the minibuffer, as appropriate.
+@end defun
+
+@node Multiple Queries
+@section Asking Multiple Y-or-N Questions
+
+  When you have a series of similar questions to ask, such as ``Do you
+want to save this buffer'' for each buffer in turn, you should use
+@code{map-y-or-n-p} to ask the collection of questions, rather than
+asking each question individually.  This gives the user certain
+convenient facilities such as the ability to answer the whole series at
+once.
+
+@defun map-y-or-n-p prompter actor list &optional help action-alist
+This function, new in Emacs 19, asks the user a series of questions,
+reading a single-character answer in the echo area for each one.
+
+The value of @var{list} specifies the objects to ask questions about.
+It should be either a list of objects or a generator function.  If it is
+a function, it should expect no arguments, and should return either the
+next object to ask about, or @code{nil} meaning stop asking questions.
+
+The argument @var{prompter} specifies how to ask each question.  If
+@var{prompter} is a string, the question text is computed like this:
+
+@example
+(format @var{prompter} @var{object})
+@end example
+
+@noindent
+where @var{object} is the next object to ask about (as obtained from
+@var{list}).
+
+If not a string, @var{prompter} should be a function of one argument
+(the next object to ask about) and should return the question text.  If
+the value is a string, that is the question to ask the user.  The
+function can also return @code{t} meaning do act on this object (and
+don't ask the user), or @code{nil} meaning ignore this object (and don't
+ask the user).
+
+The argument @var{actor} says how to act on the answers that the user
+gives.  It should be a function of one argument, and it is called with
+each object that the user says yes for.  Its argument is always an
+object obtained from @var{list}.
+
+If the argument @var{help} is given, it should be a list of this form:
+
+@example
+(@var{singular} @var{plural} @var{action})
+@end example
+
+@noindent
+where @var{singular} is a string containing a singular noun that
+describes the objects conceptually being acted on, @var{plural} is the
+corresponding plural noun, and @var{action} is a transitive verb
+describing what @var{actor} does.
+
+If you don't specify @var{help}, the default is @code{("object"
+"objects" "act on")}.
+
+Each time a question is asked, the user may enter @kbd{y}, @kbd{Y}, or
+@key{SPC} to act on that object; @kbd{n}, @kbd{N}, or @key{DEL} to skip
+that object; @kbd{!} to act on all following objects; @key{ESC} or
+@kbd{q} to exit (skip all following objects); @kbd{.} (period) to act on
+the current object and then exit; or @kbd{C-h} to get help.  These are
+the same answers that @code{query-replace} accepts.  The keymap
+@code{query-replace-map} defines their meaning for @code{map-y-or-n-p}
+as well as for @code{query-replace}; see @ref{Search and Replace}.
+
+You can use @var{action-alist} to specify additional possible answers
+and what they mean.  It is an alist of elements of the form
+@code{(@var{char} @var{function} @var{help})}, each of which defines one
+additional answer.  In this element, @var{char} is a character (the
+answer); @var{function} is a function of one argument (an object from
+@var{list}); @var{help} is a string.
+
+When the user responds with @var{char}, @code{map-y-or-n-p} calls
+@var{function}.  If it returns non-@code{nil}, the object is considered
+``acted upon'', and @code{map-y-or-n-p} advances to the next object in
+@var{list}.  If it returns @code{nil}, the prompt is repeated for the
+same object.
+
+If @code{map-y-or-n-p} is called in a command that was invoked using the
+mouse---more precisely, if @code{last-nonmenu-event} (@pxref{Command
+Loop Info}) is either @code{nil} or a list---then it uses a dialog box
+or pop-up menu to ask the question.  In this case, it does not use
+keyboard input or the echo area.  You can force use of the mouse or use
+of keyboard input by binding @code{last-nonmenu-event} to a suitable
+value around the call.
+
+The return value of @code{map-y-or-n-p} is the number of objects acted on.
+@end defun
+
+@node Minibuffer Misc
+@section Minibuffer Miscellany
+
+  This section describes some basic functions and variables related to
+minibuffers.
+
+@deffn Command exit-minibuffer
+This command exits the active minibuffer.  It is normally bound to
+keys in minibuffer local keymaps.
+@end deffn
+
+@deffn Command self-insert-and-exit
+This command exits the active minibuffer after inserting the last
+character typed on the keyboard (found in @code{last-command-char};
+@pxref{Command Loop Info}).
+@end deffn
+
+@deffn Command previous-history-element n
+This command replaces the minibuffer contents with the value of the
+@var{n}th previous (older) history element.
+@end deffn
+
+@deffn Command next-history-element n
+This command replaces the minibuffer contents with the value of the
+@var{n}th more recent history element.
+@end deffn
+
+@deffn Command previous-matching-history-element pattern
+This command replaces the minibuffer contents with the value of the
+previous (older) history element that matches @var{pattern} (a regular
+expression).
+@end deffn
+
+@deffn Command next-matching-history-element pattern
+This command replaces the minibuffer contents with the value of the next
+(newer) history element that matches @var{pattern} (a regular
+expression).
+@end deffn
+
+@defun minibuffer-prompt
+This function returns the prompt string of the currently active
+minibuffer.  If no minibuffer is active, it returns @code{nil}.
+@end defun
+
+@defun minibuffer-prompt-width
+This function returns the display width of the prompt string of the
+currently active minibuffer.  If no minibuffer is active, it returns 0.
+@end defun
+
+@defvar minibuffer-setup-hook
+This is a normal hook that is run whenever the minibuffer is entered.
+@xref{Hooks}.
+@end defvar
+
+@defvar minibuffer-exit-hook
+This is a normal hook that is run whenever the minibuffer is exited.
+@xref{Hooks}.
+@end defvar
+
+@defvar minibuffer-help-form
+The current value of this variable is used to rebind @code{help-form}
+locally inside the minibuffer (@pxref{Help Functions}).
+@end defvar
+
+@defun active-minibuffer-window
+This function returns the currently active minibuffer window, or
+@code{nil} if none is currently active.
+@end defun
+
+@defun minibuffer-window &optional frame
+This function returns the minibuffer window used for frame @var{frame}.
+If @var{frame} is @code{nil}, that stands for the current frame.  Note
+that the minibuffer window used by a frame need not be part of that
+frame---a frame that has no minibuffer of its own necessarily uses some
+other frame's minibuffer window.
+@end defun
+
+@c Emacs 19 feature
+@defun window-minibuffer-p window
+This function returns non-@code{nil} if @var{window} is a minibuffer window.
+@end defun
+
+It is not correct to determine whether a given window is a minibuffer by
+comparing it with the result of @code{(minibuffer-window)}, because
+there can be more than one minibuffer window if there is more than one
+frame.
+
+@defun minibuffer-window-active-p window
+This function returns non-@code{nil} if @var{window}, assumed to be
+a minibuffer window, is currently active.
+@end defun
+
+@defvar minibuffer-scroll-window
+If the value of this variable is non-@code{nil}, it should be a window
+object.  When the function @code{scroll-other-window} is called in the
+minibuffer, it scrolls this window.
+@end defvar
+
+Finally, some functions and variables deal with recursive minibuffers
+(@pxref{Recursive Editing}):
+
+@defun minibuffer-depth
+This function returns the current depth of activations of the
+minibuffer, a nonnegative integer.  If no minibuffers are active, it
+returns zero.
+@end defun
+
+@defopt enable-recursive-minibuffers
+If this variable is non-@code{nil}, you can invoke commands (such as
+@code{find-file}) that use minibuffers even while in the minibuffer
+window.  Such invocation produces a recursive editing level for a new
+minibuffer.  The outer-level minibuffer is invisible while you are
+editing the inner one.
+
+This variable only affects invoking the minibuffer while the
+minibuffer window is selected.   If you switch windows while in the 
+minibuffer, you can always invoke minibuffer commands while some other
+window is selected.
+@end defopt
+
+@c Emacs 19 feature
+In FSF Emacs 19, if a command name has a property
+@code{enable-recursive-minibuffers} that is non-@code{nil}, then the
+command can use the minibuffer to read arguments even if it is invoked
+from the minibuffer.  The minibuffer command
+@code{next-matching-history-element} (normally @kbd{M-s} in the
+minibuffer) uses this feature.
+
+This is not implemented in XEmacs because it is a kludge.  If you
+want to explicitly set the value of @code{enable-recursive-minibuffers}
+in this fashion, just use an evaluated interactive spec and bind
+@code{enable-recursive-minibuffers} while reading from the minibuffer.
+See the definition of @code{next-matching-history-element} in
+@file{lisp/prim/minibuf.el}.