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1 @c -*-texinfo-*-
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2 @c This is part of the XEmacs Lisp Reference Manual.
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3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1997 Free Software Foundation, Inc.
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4 @c See the file lispref.texi for copying conditions.
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5 @setfilename ../../info/minibuf.info
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6 @node Minibuffers, Command Loop, Read and Print, Top
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7 @chapter Minibuffers
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8 @cindex arguments, reading
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9 @cindex complex arguments
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10 @cindex minibuffer
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11
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12 A @dfn{minibuffer} is a special buffer that XEmacs commands use to read
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13 arguments more complicated than the single numeric prefix argument.
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14 These arguments include file names, buffer names, and command names (as
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15 in @kbd{M-x}). The minibuffer is displayed on the bottom line of the
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16 frame, in the same place as the echo area, but only while it is in
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17 use for reading an argument.
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18
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19 @menu
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20 * Intro to Minibuffers:: Basic information about minibuffers.
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21 * Text from Minibuffer:: How to read a straight text string.
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22 * Object from Minibuffer:: How to read a Lisp object or expression.
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23 * Minibuffer History:: Recording previous minibuffer inputs
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24 so the user can reuse them.
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25 * Completion:: How to invoke and customize completion.
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26 * Yes-or-No Queries:: Asking a question with a simple answer.
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27 * Multiple Queries:: Asking a series of similar questions.
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28 * Reading a Password:: Reading a password from the terminal.
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29 * Minibuffer Misc:: Various customization hooks and variables.
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30 @end menu
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31
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32 @node Intro to Minibuffers
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33 @section Introduction to Minibuffers
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34
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35 In most ways, a minibuffer is a normal XEmacs buffer. Most operations
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36 @emph{within} a buffer, such as editing commands, work normally in a
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37 minibuffer. However, many operations for managing buffers do not apply
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38 to minibuffers. The name of a minibuffer always has the form @w{@samp{
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39 *Minibuf-@var{number}}}, and it cannot be changed. Minibuffers are
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40 displayed only in special windows used only for minibuffers; these
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41 windows always appear at the bottom of a frame. (Sometimes frames have
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42 no minibuffer window, and sometimes a special kind of frame contains
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43 nothing but a minibuffer window; see @ref{Minibuffers and Frames}.)
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44
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45 The minibuffer's window is normally a single line. You can resize it
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46 temporarily with the window sizing commands; it reverts to its normal
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47 size when the minibuffer is exited. You can resize it permanently by
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48 using the window sizing commands in the frame's other window, when the
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49 minibuffer is not active. If the frame contains just a minibuffer, you
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50 can change the minibuffer's size by changing the frame's size.
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51
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52 If a command uses a minibuffer while there is an active minibuffer,
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53 this is called a @dfn{recursive minibuffer}. The first minibuffer is
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54 named @w{@samp{ *Minibuf-0*}}. Recursive minibuffers are named by
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55 incrementing the number at the end of the name. (The names begin with a
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56 space so that they won't show up in normal buffer lists.) Of several
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57 recursive minibuffers, the innermost (or most recently entered) is the
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58 active minibuffer. We usually call this ``the'' minibuffer. You can
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59 permit or forbid recursive minibuffers by setting the variable
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60 @code{enable-recursive-minibuffers}.
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61
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62 Like other buffers, a minibuffer may use any of several local keymaps
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63 (@pxref{Keymaps}); these contain various exit commands and in some cases
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64 completion commands (@pxref{Completion}).
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65
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66 @itemize @bullet
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67 @item
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68 @code{minibuffer-local-map} is for ordinary input (no completion).
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69
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70 @item
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71 @code{minibuffer-local-completion-map} is for permissive completion.
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72
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73 @item
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74 @code{minibuffer-local-must-match-map} is for strict completion and
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75 for cautious completion.
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76 @end itemize
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77
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78 @node Text from Minibuffer
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79 @section Reading Text Strings with the Minibuffer
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80
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81 Most often, the minibuffer is used to read text as a string. It can
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82 also be used to read a Lisp object in textual form. The most basic
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83 primitive for minibuffer input is @code{read-from-minibuffer}; it can do
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84 either one.
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85
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86 In most cases, you should not call minibuffer input functions in the
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87 middle of a Lisp function. Instead, do all minibuffer input as part of
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88 reading the arguments for a command, in the @code{interactive} spec.
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89 @xref{Defining Commands}.
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90
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91 @defun read-from-minibuffer prompt-string &optional initial-contents keymap read hist abbrev-table default
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92 This function is the most general way to get input through the
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93 minibuffer. By default, it accepts arbitrary text and returns it as a
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94 string; however, if @var{read} is non-@code{nil}, then it uses
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95 @code{read} to convert the text into a Lisp object (@pxref{Input
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96 Functions}).
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97
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98 The first thing this function does is to activate a minibuffer and
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99 display it with @var{prompt-string} as the prompt. This value must be a
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100 string.
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101
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102 Then, if @var{initial-contents} is a string, @code{read-from-minibuffer}
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103 inserts it into the minibuffer, leaving point at the end. The
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104 minibuffer appears with this text as its contents.
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105
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106 @c Emacs 19 feature
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107 The value of @var{initial-contents} may also be a cons cell of the form
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108 @code{(@var{string} . @var{position})}. This means to insert
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109 @var{string} in the minibuffer but put point @var{position} characters
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110 from the beginning, rather than at the end.
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111
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112 When the user types a command to exit the minibuffer,
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113 @code{read-from-minibuffer} constructs the return value from the text in
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114 the minibuffer. Normally it returns a string containing that text.
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115 However, if @var{read} is non-@code{nil}, @code{read-from-minibuffer}
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116 reads the text and returns the resulting Lisp object, unevaluated.
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117 (@xref{Input Functions}, for information about reading.)
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118
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119 The argument @var{default} specifies a default value to make available
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120 through the history commands. It should be a string, or @code{nil}.
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121
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122 If @var{keymap} is non-@code{nil}, that keymap is the local keymap to
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123 use in the minibuffer. If @var{keymap} is omitted or @code{nil}, the
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124 value of @code{minibuffer-local-map} is used as the keymap. Specifying
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125 a keymap is the most important way to customize the minibuffer for
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126 various applications such as completion.
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127
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128 The argument @var{abbrev-table} specifies @code{local-abbrev-table} in
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129 the minibuffer (@pxref{Standard Abbrev Tables}).
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130
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131 The argument @var{hist} specifies which history list variable to use
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132 for saving the input and for history commands used in the minibuffer.
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133 It defaults to @code{minibuffer-history}. @xref{Minibuffer History}.
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134
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135 When the user types a command to exit the minibuffer,
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136 @code{read-from-minibuffer} uses the text in the minibuffer to produce
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137 its return value. Normally it simply makes a string containing that
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138 text. However, if @var{read} is non-@code{nil},
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139 @code{read-from-minibuffer} reads the text and returns the resulting
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140 Lisp object, unevaluated. (@xref{Input Functions}, for information
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141 about reading.)
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142
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143 @strong{Usage note:} The @var{initial-contents} argument and the
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144 @var{default} argument are two alternative features for more or less the
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145 same job. It does not make sense to use both features in a single call
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146 to @code{read-from-minibuffer}. In general, we recommend using
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147 @var{default}, since this permits the user to insert the default value
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148 when it is wanted, but does not burden the user with deleting it from
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149 the minibuffer on other occasions. However, if user is supposed to edit
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150 default value, @var{initial-contents} may be preferred.
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151 @end defun
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152
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153 @defun read-string prompt &optional initial history default-value
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154 This function reads a string from the minibuffer and returns it. The
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155 arguments @var{prompt} and @var{initial} are used as in
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156 @code{read-from-minibuffer}. The keymap used is
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157 @code{minibuffer-local-map}.
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158
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159 The optional argument @var{history}, if non-nil, specifies a history
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160 list and optionally the initial position in the list. The optional
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161 argument @var{default} specifies a default value to return if the user
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162 enters null input; it should be a string.
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163
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164 This function is a simplified interface to the
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165 @code{read-from-minibuffer} function:
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166
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167 @smallexample
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168 @group
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169 (read-string @var{prompt} @var{initial} @var{history} @var{default})
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170 @equiv{}
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171 (read-from-minibuffer @var{prompt} @var{initial} nil nil
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172 @var{history} nil @var{default})))
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173 @end group
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174 @end smallexample
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175 @end defun
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176
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177 @defvar minibuffer-local-map
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178 This is the default local keymap for reading from the minibuffer. By
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179 default, it makes the following bindings:
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180
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181 @table @asis
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182 @item @kbd{C-j}
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183 @code{exit-minibuffer}
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184
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185 @item @key{RET}
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186 @code{exit-minibuffer}
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187
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188 @item @kbd{C-g}
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189 @code{abort-recursive-edit}
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190
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191 @item @kbd{M-n}
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192 @code{next-history-element}
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193
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194 @item @kbd{M-p}
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195 @code{previous-history-element}
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196
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197 @item @kbd{M-r}
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198 @code{next-matching-history-element}
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199
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200 @item @kbd{M-s}
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201 @code{previous-matching-history-element}
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202 @end table
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203 @end defvar
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204
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205 @node Object from Minibuffer
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206 @section Reading Lisp Objects with the Minibuffer
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207
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208 This section describes functions for reading Lisp objects with the
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209 minibuffer.
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210
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211 @defun read-expression prompt &optional initial history default-value
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212 This function reads a Lisp object using the minibuffer, and returns it
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213 without evaluating it. The arguments @var{prompt} and @var{initial} are
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214 used as in @code{read-from-minibuffer}.
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215
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216 The optional argument @var{history}, if non-nil, specifies a history
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217 list and optionally the initial position in the list. The optional
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218 argument @var{default-value} specifies a default value to return if the
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219 user enters null input; it should be a string.
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220
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221 This is a simplified interface to the
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222 @code{read-from-minibuffer} function:
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223
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224 @smallexample
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225 @group
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226 (read-expression @var{prompt} @var{initial} @var{history} @var{default-value})
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227 @equiv{}
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228 (read-from-minibuffer @var{prompt} @var{initial} nil t
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229 @var{history} nil @var{default-value})
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230 @end group
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231 @end smallexample
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232
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233 Here is an example in which we supply the string @code{"(testing)"} as
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234 initial input:
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235
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236 @smallexample
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237 @group
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238 (read-expression
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239 "Enter an expression: " (format "%s" '(testing)))
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240
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241 ;; @r{Here is how the minibuffer is displayed:}
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242 @end group
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243
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244 @group
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245 ---------- Buffer: Minibuffer ----------
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246 Enter an expression: (testing)@point{}
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247 ---------- Buffer: Minibuffer ----------
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248 @end group
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249 @end smallexample
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250
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251 @noindent
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252 The user can type @key{RET} immediately to use the initial input as a
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253 default, or can edit the input.
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254 @end defun
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255
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256 @defun read-minibuffer prompt &optional initial history default-value
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257
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258 This is a FSF Emacs compatible function. Use @code{read-expression}
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259 instead.
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260 @end defun
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261
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262 @defun eval-minibuffer prompt &optional initial history default-value
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263 This function reads a Lisp expression using the minibuffer, evaluates
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264 it, then returns the result. The arguments @var{prompt} and
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265 @var{initial} are used as in @code{read-from-minibuffer}.
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266
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267 The optional argument @var{history}, if non-nil, specifies a history
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268 list and optionally the initial position in the list. The optional
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269 argument @var{default-value} specifies a default value to return if the
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270 user enters null input; it should be a string.
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271
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272 This function simply evaluates the result of a call to
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273 @code{read-expression}:
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274
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275 @smallexample
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276 @group
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277 (eval-minibuffer @var{prompt} @var{initial})
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278 @equiv{}
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279 (eval (read-expression @var{prompt} @var{initial}))
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280 @end group
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281 @end smallexample
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282 @end defun
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283
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284 @defun edit-and-eval-command prompt command &optional history
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285 This function reads a Lisp expression in the minibuffer, and then
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286 evaluates it. The difference between this command and
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287 @code{eval-minibuffer} is that here the initial @var{command} is not
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288 optional and it is treated as a Lisp object to be converted to printed
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289 representation rather than as a string of text. It is printed with
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290 @code{prin1}, so if it is a string, double-quote characters (@samp{"})
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291 appear in the initial text. @xref{Output Functions}.
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292
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293 The first thing @code{edit-and-eval-command} does is to activate the
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294 minibuffer with @var{prompt} as the prompt. Then it inserts the printed
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295 representation of @var{form} in the minibuffer, and lets the user edit it.
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296 When the user exits the minibuffer, the edited text is read with
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297 @code{read} and then evaluated. The resulting value becomes the value
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298 of @code{edit-and-eval-command}.
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299
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300 In the following example, we offer the user an expression with initial
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301 text which is a valid form already:
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302
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303 @smallexample
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304 @group
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305 (edit-and-eval-command "Please edit: " '(forward-word 1))
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306
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307 ;; @r{After evaluation of the preceding expression,}
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308 ;; @r{the following appears in the minibuffer:}
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309 @end group
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310
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311 @group
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312 ---------- Buffer: Minibuffer ----------
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313 Please edit: (forward-word 1)@point{}
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314 ---------- Buffer: Minibuffer ----------
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315 @end group
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316 @end smallexample
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317
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318 @noindent
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319 Typing @key{RET} right away would exit the minibuffer and evaluate the
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320 expression, thus moving point forward one word.
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321 @code{edit-and-eval-command} returns @code{t} in this example.
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322 @end defun
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323
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324 @node Minibuffer History
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325 @section Minibuffer History
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326 @cindex minibuffer history
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327 @cindex history list
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328
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329 A @dfn{minibuffer history list} records previous minibuffer inputs so
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330 the user can reuse them conveniently. A history list is actually a
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331 symbol, not a list; it is a variable whose value is a list of strings
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332 (previous inputs), most recent first.
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333
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334 There are many separate history lists, used for different kinds of
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335 inputs. It's the Lisp programmer's job to specify the right history
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336 list for each use of the minibuffer.
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337
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338 The basic minibuffer input functions @code{read-from-minibuffer} and
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339 @code{completing-read} both accept an optional argument named @var{hist}
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340 which is how you specify the history list. Here are the possible
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341 values:
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342
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343 @table @asis
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344 @item @var{variable}
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345 Use @var{variable} (a symbol) as the history list.
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346
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347 @item (@var{variable} . @var{startpos})
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348 Use @var{variable} (a symbol) as the history list, and assume that the
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349 initial history position is @var{startpos} (an integer, counting from
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350 zero which specifies the most recent element of the history).
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351
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352 If you specify @var{startpos}, then you should also specify that element
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353 of the history as the initial minibuffer contents, for consistency.
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354 @end table
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355
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356 If you don't specify @var{hist}, then the default history list
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357 @code{minibuffer-history} is used. For other standard history lists,
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358 see below. You can also create your own history list variable; just
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359 initialize it to @code{nil} before the first use.
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360
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361 Both @code{read-from-minibuffer} and @code{completing-read} add new
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362 elements to the history list automatically, and provide commands to
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363 allow the user to reuse items on the list. The only thing your program
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364 needs to do to use a history list is to initialize it and to pass its
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365 name to the input functions when you wish. But it is safe to modify the
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366 list by hand when the minibuffer input functions are not using it.
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367
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368 Here are some of the standard minibuffer history list variables:
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369
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370 @defvar minibuffer-history
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371 The default history list for minibuffer history input.
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372 @end defvar
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373
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374 @defvar query-replace-history
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375 A history list for arguments to @code{query-replace} (and similar
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376 arguments to other commands).
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377 @end defvar
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378
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379 @defvar file-name-history
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380 A history list for file name arguments.
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381 @end defvar
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382
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383 @defvar regexp-history
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384 A history list for regular expression arguments.
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385 @end defvar
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386
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387 @defvar extended-command-history
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388 A history list for arguments that are names of extended commands.
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389 @end defvar
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390
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391 @defvar shell-command-history
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392 A history list for arguments that are shell commands.
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393 @end defvar
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394
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395 @defvar read-expression-history
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396 A history list for arguments that are Lisp expressions to evaluate.
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397 @end defvar
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398
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399 @defvar Info-minibuffer-history
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400 A history list for Info mode's minibuffer.
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401 @end defvar
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402
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403 @defvar Manual-page-minibuffer-history
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404 A history list for @code{manual-entry}.
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405 @end defvar
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406
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407 There are many other minibuffer history lists, defined by various
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408 libraries. An @kbd{M-x apropos} search for @samp{history} should prove
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409 fruitful in discovering them.
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410
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411 @node Completion
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412 @section Completion
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413 @cindex completion
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414
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415 @dfn{Completion} is a feature that fills in the rest of a name
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416 starting from an abbreviation for it. Completion works by comparing the
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417 user's input against a list of valid names and determining how much of
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418 the name is determined uniquely by what the user has typed. For
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419 example, when you type @kbd{C-x b} (@code{switch-to-buffer}) and then
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420 type the first few letters of the name of the buffer to which you wish
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421 to switch, and then type @key{TAB} (@code{minibuffer-complete}), Emacs
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422 extends the name as far as it can.
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423
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424 Standard XEmacs commands offer completion for names of symbols, files,
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425 buffers, and processes; with the functions in this section, you can
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426 implement completion for other kinds of names.
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427
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428 The @code{try-completion} function is the basic primitive for
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429 completion: it returns the longest determined completion of a given
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430 initial string, with a given set of strings to match against.
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|
431
|
|
432 The function @code{completing-read} provides a higher-level interface
|
|
433 for completion. A call to @code{completing-read} specifies how to
|
|
434 determine the list of valid names. The function then activates the
|
|
435 minibuffer with a local keymap that binds a few keys to commands useful
|
|
436 for completion. Other functions provide convenient simple interfaces
|
|
437 for reading certain kinds of names with completion.
|
|
438
|
|
439 @menu
|
|
440 * Basic Completion:: Low-level functions for completing strings.
|
|
441 (These are too low level to use the minibuffer.)
|
|
442 * Minibuffer Completion:: Invoking the minibuffer with completion.
|
|
443 * Completion Commands:: Minibuffer commands that do completion.
|
|
444 * High-Level Completion:: Convenient special cases of completion
|
|
445 (reading buffer name, file name, etc.)
|
|
446 * Reading File Names:: Using completion to read file names.
|
|
447 * Programmed Completion:: Finding the completions for a given file name.
|
|
448 @end menu
|
|
449
|
|
450 @node Basic Completion
|
|
451 @subsection Basic Completion Functions
|
|
452
|
|
453 The two functions @code{try-completion} and @code{all-completions}
|
|
454 have nothing in themselves to do with minibuffers. We describe them in
|
|
455 this chapter so as to keep them near the higher-level completion
|
|
456 features that do use the minibuffer.
|
|
457
|
|
458 @defun try-completion string collection &optional predicate
|
|
459 This function returns the longest common substring of all possible
|
|
460 completions of @var{string} in @var{collection}. The value of
|
|
461 @var{collection} must be an alist, an obarray, or a function that
|
|
462 implements a virtual set of strings (see below).
|
|
463
|
|
464 Completion compares @var{string} against each of the permissible
|
|
465 completions specified by @var{collection}; if the beginning of the
|
|
466 permissible completion equals @var{string}, it matches. If no permissible
|
|
467 completions match, @code{try-completion} returns @code{nil}. If only
|
|
468 one permissible completion matches, and the match is exact, then
|
|
469 @code{try-completion} returns @code{t}. Otherwise, the value is the
|
|
470 longest initial sequence common to all the permissible completions that
|
|
471 match.
|
|
472
|
|
473 If @var{collection} is an alist (@pxref{Association Lists}), the
|
|
474 @sc{car}s of the alist elements form the set of permissible completions.
|
|
475
|
|
476 @cindex obarray in completion
|
|
477 If @var{collection} is an obarray (@pxref{Creating Symbols}), the names
|
|
478 of all symbols in the obarray form the set of permissible completions. The
|
|
479 global variable @code{obarray} holds an obarray containing the names of
|
|
480 all interned Lisp symbols.
|
|
481
|
|
482 Note that the only valid way to make a new obarray is to create it
|
|
483 empty and then add symbols to it one by one using @code{intern}.
|
|
484 Also, you cannot intern a given symbol in more than one obarray.
|
|
485
|
|
486 If the argument @var{predicate} is non-@code{nil}, then it must be a
|
|
487 function of one argument. It is used to test each possible match, and
|
|
488 the match is accepted only if @var{predicate} returns non-@code{nil}.
|
|
489 The argument given to @var{predicate} is either a cons cell from the alist
|
|
490 (the @sc{car} of which is a string) or else it is a symbol (@emph{not} a
|
|
491 symbol name) from the obarray.
|
|
492
|
|
493 You can also use a symbol that is a function as @var{collection}. Then
|
|
494 the function is solely responsible for performing completion;
|
|
495 @code{try-completion} returns whatever this function returns. The
|
|
496 function is called with three arguments: @var{string}, @var{predicate}
|
|
497 and @code{nil}. (The reason for the third argument is so that the same
|
|
498 function can be used in @code{all-completions} and do the appropriate
|
|
499 thing in either case.) @xref{Programmed Completion}.
|
|
500
|
|
501 In the first of the following examples, the string @samp{foo} is
|
|
502 matched by three of the alist @sc{car}s. All of the matches begin with
|
|
503 the characters @samp{fooba}, so that is the result. In the second
|
|
504 example, there is only one possible match, and it is exact, so the value
|
|
505 is @code{t}.
|
|
506
|
|
507 @smallexample
|
|
508 @group
|
|
509 (try-completion
|
|
510 "foo"
|
|
511 '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4)))
|
|
512 @result{} "fooba"
|
|
513 @end group
|
|
514
|
|
515 @group
|
|
516 (try-completion "foo" '(("barfoo" 2) ("foo" 3)))
|
|
517 @result{} t
|
|
518 @end group
|
|
519 @end smallexample
|
|
520
|
|
521 In the following example, numerous symbols begin with the characters
|
|
522 @samp{forw}, and all of them begin with the word @samp{forward}. In
|
|
523 most of the symbols, this is followed with a @samp{-}, but not in all,
|
|
524 so no more than @samp{forward} can be completed.
|
|
525
|
|
526 @smallexample
|
|
527 @group
|
|
528 (try-completion "forw" obarray)
|
|
529 @result{} "forward"
|
|
530 @end group
|
|
531 @end smallexample
|
|
532
|
|
533 Finally, in the following example, only two of the three possible
|
|
534 matches pass the predicate @code{test} (the string @samp{foobaz} is
|
|
535 too short). Both of those begin with the string @samp{foobar}.
|
|
536
|
|
537 @smallexample
|
|
538 @group
|
|
539 (defun test (s)
|
|
540 (> (length (car s)) 6))
|
|
541 @result{} test
|
|
542 @end group
|
|
543 @group
|
|
544 (try-completion
|
|
545 "foo"
|
|
546 '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))
|
|
547 'test)
|
|
548 @result{} "foobar"
|
|
549 @end group
|
|
550 @end smallexample
|
|
551 @end defun
|
|
552
|
|
553 @defun all-completions string collection &optional predicate nospace
|
|
554 This function returns a list of all possible completions of
|
434
|
555 @var{string}. The arguments to this function are the same as those of
|
428
|
556 @code{try-completion}.
|
|
557
|
|
558 If @var{collection} is a function, it is called with three arguments:
|
|
559 @var{string}, @var{predicate} and @code{t}; then @code{all-completions}
|
|
560 returns whatever the function returns. @xref{Programmed Completion}.
|
|
561
|
|
562 If @var{nospace} is non-@code{nil}, completions that start with a space
|
|
563 are ignored unless @var{string} also starts with a space.
|
|
564
|
|
565 Here is an example, using the function @code{test} shown in the
|
|
566 example for @code{try-completion}:
|
|
567
|
|
568 @smallexample
|
|
569 @group
|
|
570 (defun test (s)
|
|
571 (> (length (car s)) 6))
|
|
572 @result{} test
|
|
573 @end group
|
|
574
|
|
575 @group
|
|
576 (all-completions
|
|
577 "foo"
|
|
578 '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))
|
|
579 'test)
|
|
580 @result{} ("foobar1" "foobar2")
|
|
581 @end group
|
|
582 @end smallexample
|
|
583 @end defun
|
|
584
|
|
585 @defvar completion-ignore-case
|
|
586 If the value of this variable is
|
|
587 non-@code{nil}, XEmacs does not consider case significant in completion.
|
|
588 @end defvar
|
|
589
|
|
590 @node Minibuffer Completion
|
|
591 @subsection Completion and the Minibuffer
|
|
592
|
|
593 This section describes the basic interface for reading from the
|
|
594 minibuffer with completion.
|
|
595
|
434
|
596 @defun completing-read prompt collection &optional predicate require-match initial hist default
|
428
|
597 This function reads a string in the minibuffer, assisting the user by
|
|
598 providing completion. It activates the minibuffer with prompt
|
|
599 @var{prompt}, which must be a string. If @var{initial} is
|
|
600 non-@code{nil}, @code{completing-read} inserts it into the minibuffer as
|
|
601 part of the input. Then it allows the user to edit the input, providing
|
|
602 several commands to attempt completion.
|
|
603
|
|
604 The actual completion is done by passing @var{collection} and
|
|
605 @var{predicate} to the function @code{try-completion}. This happens in
|
|
606 certain commands bound in the local keymaps used for completion.
|
|
607
|
|
608 If @var{require-match} is @code{t}, the usual minibuffer exit commands
|
|
609 won't exit unless the input completes to an element of @var{collection}.
|
|
610 If @var{require-match} is neither @code{nil} nor @code{t}, then the exit
|
|
611 commands won't exit unless the input typed is itself an element of
|
|
612 @var{collection}. If @var{require-match} is @code{nil}, the exit
|
|
613 commands work regardless of the input in the minibuffer.
|
|
614
|
434
|
615 However, empty input is always permitted, regardless of the value of
|
|
616 @var{require-match}; in that case, @code{completing-read} returns
|
|
617 @var{default}. The value of @var{default} (if non-@code{nil}) is also
|
|
618 available to the user through the history commands.
|
|
619
|
428
|
620 The user can exit with null input by typing @key{RET} with an empty
|
434
|
621 minibuffer. Then @code{completing-read} returns @code{""}. This is how
|
|
622 the user requests whatever default the command uses for the value being
|
|
623 read. The user can return using @key{RET} in this way regardless of the
|
|
624 value of @var{require-match}, and regardless of whether the empty string
|
|
625 is included in @var{collection}.
|
428
|
626
|
|
627 The function @code{completing-read} works by calling
|
442
|
628 @code{read-expression}. It uses @code{minibuffer-local-completion-map}
|
428
|
629 as the keymap if @var{require-match} is @code{nil}, and uses
|
|
630 @code{minibuffer-local-must-match-map} if @var{require-match} is
|
|
631 non-@code{nil}. @xref{Completion Commands}.
|
|
632
|
|
633 The argument @var{hist} specifies which history list variable to use for
|
|
634 saving the input and for minibuffer history commands. It defaults to
|
|
635 @code{minibuffer-history}. @xref{Minibuffer History}.
|
|
636
|
|
637 Completion ignores case when comparing the input against the possible
|
|
638 matches, if the built-in variable @code{completion-ignore-case} is
|
|
639 non-@code{nil}. @xref{Basic Completion}.
|
|
640
|
|
641 Here's an example of using @code{completing-read}:
|
|
642
|
|
643 @smallexample
|
|
644 @group
|
|
645 (completing-read
|
|
646 "Complete a foo: "
|
|
647 '(("foobar1" 1) ("barfoo" 2) ("foobaz" 3) ("foobar2" 4))
|
|
648 nil t "fo")
|
|
649 @end group
|
|
650
|
|
651 @group
|
|
652 ;; @r{After evaluation of the preceding expression,}
|
|
653 ;; @r{the following appears in the minibuffer:}
|
|
654
|
|
655 ---------- Buffer: Minibuffer ----------
|
|
656 Complete a foo: fo@point{}
|
|
657 ---------- Buffer: Minibuffer ----------
|
|
658 @end group
|
|
659 @end smallexample
|
|
660
|
|
661 @noindent
|
|
662 If the user then types @kbd{@key{DEL} @key{DEL} b @key{RET}},
|
|
663 @code{completing-read} returns @code{barfoo}.
|
|
664
|
|
665 The @code{completing-read} function binds three variables to pass
|
|
666 information to the commands that actually do completion. These
|
|
667 variables are @code{minibuffer-completion-table},
|
|
668 @code{minibuffer-completion-predicate} and
|
|
669 @code{minibuffer-completion-confirm}. For more information about them,
|
|
670 see @ref{Completion Commands}.
|
|
671 @end defun
|
|
672
|
|
673 @node Completion Commands
|
|
674 @subsection Minibuffer Commands That Do Completion
|
|
675
|
|
676 This section describes the keymaps, commands and user options used in
|
|
677 the minibuffer to do completion.
|
|
678
|
|
679 @defvar minibuffer-local-completion-map
|
|
680 @code{completing-read} uses this value as the local keymap when an
|
|
681 exact match of one of the completions is not required. By default, this
|
|
682 keymap makes the following bindings:
|
|
683
|
|
684 @table @asis
|
|
685 @item @kbd{?}
|
|
686 @code{minibuffer-completion-help}
|
|
687
|
|
688 @item @key{SPC}
|
|
689 @code{minibuffer-complete-word}
|
|
690
|
|
691 @item @key{TAB}
|
|
692 @code{minibuffer-complete}
|
|
693 @end table
|
|
694
|
|
695 @noindent
|
|
696 with other characters bound as in @code{minibuffer-local-map}
|
|
697 (@pxref{Text from Minibuffer}).
|
|
698 @end defvar
|
|
699
|
|
700 @defvar minibuffer-local-must-match-map
|
|
701 @code{completing-read} uses this value as the local keymap when an
|
|
702 exact match of one of the completions is required. Therefore, no keys
|
|
703 are bound to @code{exit-minibuffer}, the command that exits the
|
|
704 minibuffer unconditionally. By default, this keymap makes the following
|
|
705 bindings:
|
|
706
|
|
707 @table @asis
|
|
708 @item @kbd{?}
|
|
709 @code{minibuffer-completion-help}
|
|
710
|
|
711 @item @key{SPC}
|
|
712 @code{minibuffer-complete-word}
|
|
713
|
|
714 @item @key{TAB}
|
|
715 @code{minibuffer-complete}
|
|
716
|
434
|
717 @item @kbd{C-j}
|
428
|
718 @code{minibuffer-complete-and-exit}
|
|
719
|
|
720 @item @key{RET}
|
|
721 @code{minibuffer-complete-and-exit}
|
|
722 @end table
|
|
723
|
|
724 @noindent
|
|
725 with other characters bound as in @code{minibuffer-local-map}.
|
|
726 @end defvar
|
|
727
|
|
728 @defvar minibuffer-completion-table
|
|
729 The value of this variable is the alist or obarray used for completion
|
|
730 in the minibuffer. This is the global variable that contains what
|
|
731 @code{completing-read} passes to @code{try-completion}. It is used by
|
|
732 minibuffer completion commands such as @code{minibuffer-complete-word}.
|
|
733 @end defvar
|
|
734
|
|
735 @defvar minibuffer-completion-predicate
|
|
736 This variable's value is the predicate that @code{completing-read}
|
|
737 passes to @code{try-completion}. The variable is also used by the other
|
|
738 minibuffer completion functions.
|
|
739 @end defvar
|
|
740
|
|
741 @deffn Command minibuffer-complete-word
|
|
742 This function completes the minibuffer contents by at most a single
|
|
743 word. Even if the minibuffer contents have only one completion,
|
|
744 @code{minibuffer-complete-word} does not add any characters beyond the
|
|
745 first character that is not a word constituent. @xref{Syntax Tables}.
|
|
746 @end deffn
|
|
747
|
|
748 @deffn Command minibuffer-complete
|
|
749 This function completes the minibuffer contents as far as possible.
|
|
750 @end deffn
|
|
751
|
|
752 @deffn Command minibuffer-complete-and-exit
|
|
753 This function completes the minibuffer contents, and exits if
|
|
754 confirmation is not required, i.e., if
|
434
|
755 @code{minibuffer-completion-confirm} is @code{nil}. If confirmation
|
428
|
756 @emph{is} required, it is given by repeating this command
|
|
757 immediately---the command is programmed to work without confirmation
|
|
758 when run twice in succession.
|
|
759 @end deffn
|
|
760
|
|
761 @defvar minibuffer-completion-confirm
|
|
762 When the value of this variable is non-@code{nil}, XEmacs asks for
|
|
763 confirmation of a completion before exiting the minibuffer. The
|
|
764 function @code{minibuffer-complete-and-exit} checks the value of this
|
|
765 variable before it exits.
|
|
766 @end defvar
|
|
767
|
|
768 @deffn Command minibuffer-completion-help
|
|
769 This function creates a list of the possible completions of the
|
|
770 current minibuffer contents. It works by calling @code{all-completions}
|
|
771 using the value of the variable @code{minibuffer-completion-table} as
|
|
772 the @var{collection} argument, and the value of
|
|
773 @code{minibuffer-completion-predicate} as the @var{predicate} argument.
|
|
774 The list of completions is displayed as text in a buffer named
|
|
775 @samp{*Completions*}.
|
|
776 @end deffn
|
|
777
|
442
|
778 @defun display-completion-list completions &rest cl-keys
|
428
|
779 This function displays @var{completions} to the stream in
|
|
780 @code{standard-output}, usually a buffer. (@xref{Read and Print}, for more
|
|
781 information about streams.) The argument @var{completions} is normally
|
|
782 a list of completions just returned by @code{all-completions}, but it
|
|
783 does not have to be. Each element may be a symbol or a string, either
|
|
784 of which is simply printed, or a list of two strings, which is printed
|
|
785 as if the strings were concatenated.
|
|
786
|
|
787 This function is called by @code{minibuffer-completion-help}. The
|
|
788 most common way to use it is together with
|
|
789 @code{with-output-to-temp-buffer}, like this:
|
|
790
|
|
791 @example
|
|
792 (with-output-to-temp-buffer "*Completions*"
|
|
793 (display-completion-list
|
|
794 (all-completions (buffer-string) my-alist)))
|
|
795 @end example
|
|
796 @end defun
|
|
797
|
|
798 @defopt completion-auto-help
|
|
799 If this variable is non-@code{nil}, the completion commands
|
|
800 automatically display a list of possible completions whenever nothing
|
|
801 can be completed because the next character is not uniquely determined.
|
|
802 @end defopt
|
|
803
|
|
804 @node High-Level Completion
|
|
805 @subsection High-Level Completion Functions
|
|
806
|
|
807 This section describes the higher-level convenient functions for
|
|
808 reading certain sorts of names with completion.
|
|
809
|
|
810 In most cases, you should not call these functions in the middle of a
|
|
811 Lisp function. When possible, do all minibuffer input as part of
|
|
812 reading the arguments for a command, in the @code{interactive} spec.
|
|
813 @xref{Defining Commands}.
|
|
814
|
|
815 @defun read-buffer prompt &optional default existing
|
|
816 This function reads the name of a buffer and returns it as a string.
|
|
817 The argument @var{default} is the default name to use, the value to
|
|
818 return if the user exits with an empty minibuffer. If non-@code{nil},
|
|
819 it should be a string or a buffer. It is mentioned in the prompt, but
|
|
820 is not inserted in the minibuffer as initial input.
|
|
821
|
|
822 If @var{existing} is non-@code{nil}, then the name specified must be
|
|
823 that of an existing buffer. The usual commands to exit the minibuffer
|
|
824 do not exit if the text is not valid, and @key{RET} does completion to
|
|
825 attempt to find a valid name. (However, @var{default} is not checked
|
|
826 for validity; it is returned, whatever it is, if the user exits with the
|
|
827 minibuffer empty.)
|
|
828
|
|
829 In the following example, the user enters @samp{minibuffer.t}, and
|
|
830 then types @key{RET}. The argument @var{existing} is @code{t}, and the
|
|
831 only buffer name starting with the given input is
|
|
832 @samp{minibuffer.texi}, so that name is the value.
|
|
833
|
|
834 @example
|
|
835 (read-buffer "Buffer name? " "foo" t)
|
|
836 @group
|
|
837 ;; @r{After evaluation of the preceding expression,}
|
|
838 ;; @r{the following prompt appears,}
|
|
839 ;; @r{with an empty minibuffer:}
|
|
840 @end group
|
|
841
|
|
842 @group
|
|
843 ---------- Buffer: Minibuffer ----------
|
|
844 Buffer name? (default foo) @point{}
|
|
845 ---------- Buffer: Minibuffer ----------
|
|
846 @end group
|
|
847
|
|
848 @group
|
|
849 ;; @r{The user types @kbd{minibuffer.t @key{RET}}.}
|
|
850 @result{} "minibuffer.texi"
|
|
851 @end group
|
|
852 @end example
|
|
853 @end defun
|
|
854
|
442
|
855 @defun read-command prompt &optional default-value
|
428
|
856 This function reads the name of a command and returns it as a Lisp
|
|
857 symbol. The argument @var{prompt} is used as in
|
|
858 @code{read-from-minibuffer}. Recall that a command is anything for
|
|
859 which @code{commandp} returns @code{t}, and a command name is a symbol
|
|
860 for which @code{commandp} returns @code{t}. @xref{Interactive Call}.
|
|
861
|
442
|
862 The argument @var{default-value} specifies what to return if the user
|
|
863 enters null input. It can be a symbol or a string; if it is a string,
|
|
864 @code{read-command} interns it before returning it. If @var{default} is
|
|
865 @code{nil}, that means no default has been specified; then if the user
|
|
866 enters null input, the return value is @code{nil}.
|
|
867
|
428
|
868 @example
|
|
869 (read-command "Command name? ")
|
|
870
|
|
871 @group
|
|
872 ;; @r{After evaluation of the preceding expression,}
|
|
873 ;; @r{the following prompt appears with an empty minibuffer:}
|
|
874 @end group
|
|
875
|
|
876 @group
|
|
877 ---------- Buffer: Minibuffer ----------
|
|
878 Command name?
|
|
879 ---------- Buffer: Minibuffer ----------
|
|
880 @end group
|
|
881 @end example
|
|
882
|
|
883 @noindent
|
|
884 If the user types @kbd{forward-c @key{RET}}, then this function returns
|
|
885 @code{forward-char}.
|
|
886
|
|
887 The @code{read-command} function is a simplified interface to the
|
|
888 function @code{completing-read}. It uses the variable @code{obarray} so
|
|
889 as to complete in the set of extant Lisp symbols, and it uses the
|
|
890 @code{commandp} predicate so as to accept only command names:
|
|
891
|
|
892 @cindex @code{commandp} example
|
|
893 @example
|
|
894 @group
|
|
895 (read-command @var{prompt})
|
|
896 @equiv{}
|
|
897 (intern (completing-read @var{prompt} obarray
|
|
898 'commandp t nil))
|
|
899 @end group
|
|
900 @end example
|
|
901 @end defun
|
|
902
|
442
|
903 @defun read-variable prompt &optional default-value
|
428
|
904 This function reads the name of a user variable and returns it as a
|
|
905 symbol.
|
|
906
|
442
|
907 The argument @var{default-value} specifies what to return if the user
|
|
908 enters null input. It can be a symbol or a string; if it is a string,
|
|
909 @code{read-variable} interns it before returning it. If @var{default}
|
|
910 is @code{nil}, that means no default has been specified; then if the
|
|
911 user enters null input, the return value is @code{nil}.
|
|
912
|
428
|
913 @example
|
|
914 @group
|
|
915 (read-variable "Variable name? ")
|
|
916
|
|
917 ;; @r{After evaluation of the preceding expression,}
|
|
918 ;; @r{the following prompt appears,}
|
|
919 ;; @r{with an empty minibuffer:}
|
|
920 @end group
|
|
921
|
|
922 @group
|
|
923 ---------- Buffer: Minibuffer ----------
|
|
924 Variable name? @point{}
|
|
925 ---------- Buffer: Minibuffer ----------
|
|
926 @end group
|
|
927 @end example
|
|
928
|
|
929 @noindent
|
|
930 If the user then types @kbd{fill-p @key{RET}}, @code{read-variable}
|
|
931 returns @code{fill-prefix}.
|
|
932
|
|
933 This function is similar to @code{read-command}, but uses the
|
|
934 predicate @code{user-variable-p} instead of @code{commandp}:
|
|
935
|
|
936 @cindex @code{user-variable-p} example
|
|
937 @example
|
|
938 @group
|
|
939 (read-variable @var{prompt})
|
|
940 @equiv{}
|
|
941 (intern
|
|
942 (completing-read @var{prompt} obarray
|
|
943 'user-variable-p t nil))
|
|
944 @end group
|
|
945 @end example
|
|
946 @end defun
|
|
947
|
|
948 @node Reading File Names
|
|
949 @subsection Reading File Names
|
|
950
|
|
951 Here is another high-level completion function, designed for reading a
|
|
952 file name. It provides special features including automatic insertion
|
|
953 of the default directory.
|
|
954
|
442
|
955 @defun read-file-name prompt &optional directory default existing initial history
|
428
|
956 This function reads a file name in the minibuffer, prompting with
|
|
957 @var{prompt} and providing completion. If @var{default} is
|
|
958 non-@code{nil}, then the function returns @var{default} if the user just
|
|
959 types @key{RET}. @var{default} is not checked for validity; it is
|
|
960 returned, whatever it is, if the user exits with the minibuffer empty.
|
|
961
|
|
962 If @var{existing} is non-@code{nil}, then the user must specify the name
|
|
963 of an existing file; @key{RET} performs completion to make the name
|
|
964 valid if possible, and then refuses to exit if it is not valid. If the
|
|
965 value of @var{existing} is neither @code{nil} nor @code{t}, then
|
|
966 @key{RET} also requires confirmation after completion. If
|
|
967 @var{existing} is @code{nil}, then the name of a nonexistent file is
|
|
968 acceptable.
|
|
969
|
|
970 The argument @var{directory} specifies the directory to use for
|
|
971 completion of relative file names. If @code{insert-default-directory}
|
|
972 is non-@code{nil}, @var{directory} is also inserted in the minibuffer as
|
|
973 initial input. It defaults to the current buffer's value of
|
|
974 @code{default-directory}.
|
|
975
|
|
976 @c Emacs 19 feature
|
|
977 If you specify @var{initial}, that is an initial file name to insert in
|
434
|
978 the buffer (after @var{directory}, if that is inserted). In this
|
428
|
979 case, point goes at the beginning of @var{initial}. The default for
|
|
980 @var{initial} is @code{nil}---don't insert any file name. To see what
|
|
981 @var{initial} does, try the command @kbd{C-x C-v}.
|
|
982
|
|
983 Here is an example:
|
|
984
|
|
985 @example
|
|
986 @group
|
|
987 (read-file-name "The file is ")
|
|
988
|
|
989 ;; @r{After evaluation of the preceding expression,}
|
|
990 ;; @r{the following appears in the minibuffer:}
|
|
991 @end group
|
|
992
|
|
993 @group
|
|
994 ---------- Buffer: Minibuffer ----------
|
|
995 The file is /gp/gnu/elisp/@point{}
|
|
996 ---------- Buffer: Minibuffer ----------
|
|
997 @end group
|
|
998 @end example
|
|
999
|
|
1000 @noindent
|
|
1001 Typing @kbd{manual @key{TAB}} results in the following:
|
|
1002
|
|
1003 @example
|
|
1004 @group
|
|
1005 ---------- Buffer: Minibuffer ----------
|
|
1006 The file is /gp/gnu/elisp/manual.texi@point{}
|
|
1007 ---------- Buffer: Minibuffer ----------
|
|
1008 @end group
|
|
1009 @end example
|
|
1010
|
|
1011 @c Wordy to avoid overfull hbox in smallbook mode.
|
|
1012 @noindent
|
|
1013 If the user types @key{RET}, @code{read-file-name} returns the file name
|
|
1014 as the string @code{"/gp/gnu/elisp/manual.texi"}.
|
|
1015 @end defun
|
|
1016
|
|
1017 @defopt insert-default-directory
|
|
1018 This variable is used by @code{read-file-name}. Its value controls
|
|
1019 whether @code{read-file-name} starts by placing the name of the default
|
|
1020 directory in the minibuffer, plus the initial file name if any. If the
|
|
1021 value of this variable is @code{nil}, then @code{read-file-name} does
|
|
1022 not place any initial input in the minibuffer (unless you specify
|
|
1023 initial input with the @var{initial} argument). In that case, the
|
|
1024 default directory is still used for completion of relative file names,
|
|
1025 but is not displayed.
|
|
1026
|
|
1027 For example:
|
|
1028
|
|
1029 @example
|
|
1030 @group
|
|
1031 ;; @r{Here the minibuffer starts out with the default directory.}
|
|
1032 (let ((insert-default-directory t))
|
|
1033 (read-file-name "The file is "))
|
|
1034 @end group
|
|
1035
|
|
1036 @group
|
|
1037 ---------- Buffer: Minibuffer ----------
|
|
1038 The file is ~lewis/manual/@point{}
|
|
1039 ---------- Buffer: Minibuffer ----------
|
|
1040 @end group
|
|
1041
|
|
1042 @group
|
|
1043 ;; @r{Here the minibuffer is empty and only the prompt}
|
|
1044 ;; @r{appears on its line.}
|
|
1045 (let ((insert-default-directory nil))
|
|
1046 (read-file-name "The file is "))
|
|
1047 @end group
|
|
1048
|
|
1049 @group
|
|
1050 ---------- Buffer: Minibuffer ----------
|
|
1051 The file is @point{}
|
|
1052 ---------- Buffer: Minibuffer ----------
|
|
1053 @end group
|
|
1054 @end example
|
|
1055 @end defopt
|
|
1056
|
|
1057 @node Programmed Completion
|
|
1058 @subsection Programmed Completion
|
|
1059 @cindex programmed completion
|
|
1060
|
|
1061 Sometimes it is not possible to create an alist or an obarray
|
|
1062 containing all the intended possible completions. In such a case, you
|
|
1063 can supply your own function to compute the completion of a given string.
|
|
1064 This is called @dfn{programmed completion}.
|
|
1065
|
|
1066 To use this feature, pass a symbol with a function definition as the
|
|
1067 @var{collection} argument to @code{completing-read}. The function
|
|
1068 @code{completing-read} arranges to pass your completion function along
|
|
1069 to @code{try-completion} and @code{all-completions}, which will then let
|
|
1070 your function do all the work.
|
|
1071
|
|
1072 The completion function should accept three arguments:
|
|
1073
|
|
1074 @itemize @bullet
|
|
1075 @item
|
|
1076 The string to be completed.
|
|
1077
|
|
1078 @item
|
|
1079 The predicate function to filter possible matches, or @code{nil} if
|
|
1080 none. Your function should call the predicate for each possible match,
|
|
1081 and ignore the possible match if the predicate returns @code{nil}.
|
|
1082
|
|
1083 @item
|
|
1084 A flag specifying the type of operation.
|
|
1085 @end itemize
|
|
1086
|
|
1087 There are three flag values for three operations:
|
|
1088
|
|
1089 @itemize @bullet
|
|
1090 @item
|
|
1091 @code{nil} specifies @code{try-completion}. The completion function
|
|
1092 should return the completion of the specified string, or @code{t} if the
|
434
|
1093 string is a unique and exact match already, or @code{nil} if the string
|
|
1094 matches no possibility.
|
|
1095
|
|
1096 If the string is an exact match for one possibility, but also matches
|
|
1097 other longer possibilities, the function should return the string, not
|
|
1098 @code{t}.
|
428
|
1099
|
|
1100 @item
|
|
1101 @code{t} specifies @code{all-completions}. The completion function
|
|
1102 should return a list of all possible completions of the specified
|
|
1103 string.
|
|
1104
|
|
1105 @item
|
|
1106 @code{lambda} specifies a test for an exact match. The completion
|
|
1107 function should return @code{t} if the specified string is an exact
|
|
1108 match for some possibility; @code{nil} otherwise.
|
|
1109 @end itemize
|
|
1110
|
|
1111 It would be consistent and clean for completion functions to allow
|
|
1112 lambda expressions (lists that are functions) as well as function
|
|
1113 symbols as @var{collection}, but this is impossible. Lists as
|
|
1114 completion tables are already assigned another meaning---as alists. It
|
|
1115 would be unreliable to fail to handle an alist normally because it is
|
|
1116 also a possible function. So you must arrange for any function you wish
|
|
1117 to use for completion to be encapsulated in a symbol.
|
|
1118
|
|
1119 Emacs uses programmed completion when completing file names.
|
|
1120 @xref{File Name Completion}.
|
|
1121
|
|
1122 @node Yes-or-No Queries
|
|
1123 @section Yes-or-No Queries
|
|
1124 @cindex asking the user questions
|
|
1125 @cindex querying the user
|
|
1126 @cindex yes-or-no questions
|
|
1127
|
|
1128 This section describes functions used to ask the user a yes-or-no
|
|
1129 question. The function @code{y-or-n-p} can be answered with a single
|
|
1130 character; it is useful for questions where an inadvertent wrong answer
|
|
1131 will not have serious consequences. @code{yes-or-no-p} is suitable for
|
|
1132 more momentous questions, since it requires three or four characters to
|
|
1133 answer. Variations of these functions can be used to ask a yes-or-no
|
|
1134 question using a dialog box, or optionally using one.
|
|
1135
|
|
1136 If either of these functions is called in a command that was invoked
|
|
1137 using the mouse, then it uses a dialog box or pop-up menu to ask the
|
|
1138 question. Otherwise, it uses keyboard input.
|
|
1139
|
|
1140 Strictly speaking, @code{yes-or-no-p} uses the minibuffer and
|
|
1141 @code{y-or-n-p} does not; but it seems best to describe them together.
|
|
1142
|
|
1143 @defun y-or-n-p prompt
|
|
1144 This function asks the user a question, expecting input in the echo
|
|
1145 area. It returns @code{t} if the user types @kbd{y}, @code{nil} if the
|
|
1146 user types @kbd{n}. This function also accepts @key{SPC} to mean yes
|
|
1147 and @key{DEL} to mean no. It accepts @kbd{C-]} to mean ``quit'', like
|
|
1148 @kbd{C-g}, because the question might look like a minibuffer and for
|
|
1149 that reason the user might try to use @kbd{C-]} to get out. The answer
|
|
1150 is a single character, with no @key{RET} needed to terminate it. Upper
|
|
1151 and lower case are equivalent.
|
|
1152
|
|
1153 ``Asking the question'' means printing @var{prompt} in the echo area,
|
|
1154 followed by the string @w{@samp{(y or n) }}. If the input is not one of
|
|
1155 the expected answers (@kbd{y}, @kbd{n}, @kbd{@key{SPC}},
|
|
1156 @kbd{@key{DEL}}, or something that quits), the function responds
|
|
1157 @samp{Please answer y or n.}, and repeats the request.
|
|
1158
|
|
1159 This function does not actually use the minibuffer, since it does not
|
|
1160 allow editing of the answer. It actually uses the echo area (@pxref{The
|
|
1161 Echo Area}), which uses the same screen space as the minibuffer. The
|
|
1162 cursor moves to the echo area while the question is being asked.
|
|
1163
|
|
1164 The answers and their meanings, even @samp{y} and @samp{n}, are not
|
|
1165 hardwired. The keymap @code{query-replace-map} specifies them.
|
|
1166 @xref{Search and Replace}.
|
|
1167
|
|
1168 In the following example, the user first types @kbd{q}, which is
|
|
1169 invalid. At the next prompt the user types @kbd{y}.
|
|
1170
|
|
1171 @smallexample
|
|
1172 @group
|
|
1173 (y-or-n-p "Do you need a lift? ")
|
|
1174
|
|
1175 ;; @r{After evaluation of the preceding expression,}
|
|
1176 ;; @r{the following prompt appears in the echo area:}
|
|
1177 @end group
|
|
1178
|
|
1179 @group
|
|
1180 ---------- Echo area ----------
|
|
1181 Do you need a lift? (y or n)
|
|
1182 ---------- Echo area ----------
|
|
1183 @end group
|
|
1184
|
|
1185 ;; @r{If the user then types @kbd{q}, the following appears:}
|
|
1186
|
|
1187 @group
|
|
1188 ---------- Echo area ----------
|
|
1189 Please answer y or n. Do you need a lift? (y or n)
|
|
1190 ---------- Echo area ----------
|
|
1191 @end group
|
|
1192
|
|
1193 ;; @r{When the user types a valid answer,}
|
|
1194 ;; @r{it is displayed after the question:}
|
|
1195
|
|
1196 @group
|
|
1197 ---------- Echo area ----------
|
|
1198 Do you need a lift? (y or n) y
|
|
1199 ---------- Echo area ----------
|
|
1200 @end group
|
|
1201 @end smallexample
|
|
1202
|
|
1203 @noindent
|
|
1204 We show successive lines of echo area messages, but only one actually
|
|
1205 appears on the screen at a time.
|
|
1206 @end defun
|
|
1207
|
|
1208 @defun yes-or-no-p prompt
|
|
1209 This function asks the user a question, expecting input in the
|
|
1210 minibuffer. It returns @code{t} if the user enters @samp{yes},
|
|
1211 @code{nil} if the user types @samp{no}. The user must type @key{RET} to
|
|
1212 finalize the response. Upper and lower case are equivalent.
|
|
1213
|
|
1214 @code{yes-or-no-p} starts by displaying @var{prompt} in the echo area,
|
|
1215 followed by @w{@samp{(yes or no) }}. The user must type one of the
|
|
1216 expected responses; otherwise, the function responds @samp{Please answer
|
|
1217 yes or no.}, waits about two seconds and repeats the request.
|
|
1218
|
|
1219 @code{yes-or-no-p} requires more work from the user than
|
|
1220 @code{y-or-n-p} and is appropriate for more crucial decisions.
|
|
1221
|
|
1222 Here is an example:
|
|
1223
|
|
1224 @smallexample
|
|
1225 @group
|
|
1226 (yes-or-no-p "Do you really want to remove everything? ")
|
|
1227
|
|
1228 ;; @r{After evaluation of the preceding expression,}
|
|
1229 ;; @r{the following prompt appears,}
|
|
1230 ;; @r{with an empty minibuffer:}
|
|
1231 @end group
|
|
1232
|
|
1233 @group
|
|
1234 ---------- Buffer: minibuffer ----------
|
|
1235 Do you really want to remove everything? (yes or no)
|
|
1236 ---------- Buffer: minibuffer ----------
|
|
1237 @end group
|
|
1238 @end smallexample
|
|
1239
|
|
1240 @noindent
|
|
1241 If the user first types @kbd{y @key{RET}}, which is invalid because this
|
|
1242 function demands the entire word @samp{yes}, it responds by displaying
|
|
1243 these prompts, with a brief pause between them:
|
|
1244
|
|
1245 @smallexample
|
|
1246 @group
|
|
1247 ---------- Buffer: minibuffer ----------
|
|
1248 Please answer yes or no.
|
|
1249 Do you really want to remove everything? (yes or no)
|
|
1250 ---------- Buffer: minibuffer ----------
|
|
1251 @end group
|
|
1252 @end smallexample
|
|
1253 @end defun
|
|
1254
|
|
1255 @c The rest is XEmacs stuff
|
|
1256 @defun yes-or-no-p-dialog-box prompt
|
|
1257 This function asks the user a ``y or n'' question with a popup dialog
|
|
1258 box. It returns @code{t} if the answer is ``yes''. @var{prompt} is the
|
|
1259 string to display to ask the question.
|
|
1260 @end defun
|
|
1261
|
|
1262 The following functions ask a question either in the minibuffer or a
|
|
1263 dialog box, depending on whether the last user event (which presumably
|
|
1264 invoked this command) was a keyboard or mouse event. When XEmacs is
|
|
1265 running on a window system, the functions @code{y-or-n-p} and
|
|
1266 @code{yes-or-no-p} are replaced with the following functions, so that
|
|
1267 menu items bring up dialog boxes instead of minibuffer questions.
|
|
1268
|
|
1269 @defun y-or-n-p-maybe-dialog-box prompt
|
|
1270 This function asks user a ``y or n'' question, using either a dialog box
|
|
1271 or the minibuffer, as appropriate.
|
|
1272 @end defun
|
|
1273
|
|
1274 @defun yes-or-no-p-maybe-dialog-box prompt
|
|
1275 This function asks user a ``yes or no'' question, using either a dialog
|
|
1276 box or the minibuffer, as appropriate.
|
|
1277 @end defun
|
|
1278
|
|
1279 @node Multiple Queries
|
|
1280 @section Asking Multiple Y-or-N Questions
|
|
1281
|
|
1282 When you have a series of similar questions to ask, such as ``Do you
|
|
1283 want to save this buffer'' for each buffer in turn, you should use
|
|
1284 @code{map-y-or-n-p} to ask the collection of questions, rather than
|
|
1285 asking each question individually. This gives the user certain
|
|
1286 convenient facilities such as the ability to answer the whole series at
|
|
1287 once.
|
|
1288
|
|
1289 @defun map-y-or-n-p prompter actor list &optional help action-alist
|
|
1290 This function, new in Emacs 19, asks the user a series of questions,
|
|
1291 reading a single-character answer in the echo area for each one.
|
|
1292
|
|
1293 The value of @var{list} specifies the objects to ask questions about.
|
|
1294 It should be either a list of objects or a generator function. If it is
|
|
1295 a function, it should expect no arguments, and should return either the
|
|
1296 next object to ask about, or @code{nil} meaning stop asking questions.
|
|
1297
|
|
1298 The argument @var{prompter} specifies how to ask each question. If
|
|
1299 @var{prompter} is a string, the question text is computed like this:
|
|
1300
|
|
1301 @example
|
|
1302 (format @var{prompter} @var{object})
|
|
1303 @end example
|
|
1304
|
|
1305 @noindent
|
|
1306 where @var{object} is the next object to ask about (as obtained from
|
|
1307 @var{list}).
|
|
1308
|
|
1309 If not a string, @var{prompter} should be a function of one argument
|
|
1310 (the next object to ask about) and should return the question text. If
|
|
1311 the value is a string, that is the question to ask the user. The
|
|
1312 function can also return @code{t} meaning do act on this object (and
|
|
1313 don't ask the user), or @code{nil} meaning ignore this object (and don't
|
|
1314 ask the user).
|
|
1315
|
|
1316 The argument @var{actor} says how to act on the answers that the user
|
|
1317 gives. It should be a function of one argument, and it is called with
|
|
1318 each object that the user says yes for. Its argument is always an
|
|
1319 object obtained from @var{list}.
|
|
1320
|
|
1321 If the argument @var{help} is given, it should be a list of this form:
|
|
1322
|
|
1323 @example
|
|
1324 (@var{singular} @var{plural} @var{action})
|
|
1325 @end example
|
|
1326
|
|
1327 @noindent
|
|
1328 where @var{singular} is a string containing a singular noun that
|
|
1329 describes the objects conceptually being acted on, @var{plural} is the
|
|
1330 corresponding plural noun, and @var{action} is a transitive verb
|
|
1331 describing what @var{actor} does.
|
|
1332
|
|
1333 If you don't specify @var{help}, the default is @code{("object"
|
|
1334 "objects" "act on")}.
|
|
1335
|
|
1336 Each time a question is asked, the user may enter @kbd{y}, @kbd{Y}, or
|
|
1337 @key{SPC} to act on that object; @kbd{n}, @kbd{N}, or @key{DEL} to skip
|
|
1338 that object; @kbd{!} to act on all following objects; @key{ESC} or
|
|
1339 @kbd{q} to exit (skip all following objects); @kbd{.} (period) to act on
|
|
1340 the current object and then exit; or @kbd{C-h} to get help. These are
|
|
1341 the same answers that @code{query-replace} accepts. The keymap
|
|
1342 @code{query-replace-map} defines their meaning for @code{map-y-or-n-p}
|
|
1343 as well as for @code{query-replace}; see @ref{Search and Replace}.
|
|
1344
|
|
1345 You can use @var{action-alist} to specify additional possible answers
|
|
1346 and what they mean. It is an alist of elements of the form
|
|
1347 @code{(@var{char} @var{function} @var{help})}, each of which defines one
|
|
1348 additional answer. In this element, @var{char} is a character (the
|
|
1349 answer); @var{function} is a function of one argument (an object from
|
|
1350 @var{list}); @var{help} is a string.
|
|
1351
|
|
1352 When the user responds with @var{char}, @code{map-y-or-n-p} calls
|
|
1353 @var{function}. If it returns non-@code{nil}, the object is considered
|
|
1354 ``acted upon'', and @code{map-y-or-n-p} advances to the next object in
|
|
1355 @var{list}. If it returns @code{nil}, the prompt is repeated for the
|
|
1356 same object.
|
|
1357
|
|
1358 If @code{map-y-or-n-p} is called in a command that was invoked using the
|
|
1359 mouse---more precisely, if @code{last-nonmenu-event} (@pxref{Command
|
|
1360 Loop Info}) is either @code{nil} or a list---then it uses a dialog box
|
|
1361 or pop-up menu to ask the question. In this case, it does not use
|
|
1362 keyboard input or the echo area. You can force use of the mouse or use
|
|
1363 of keyboard input by binding @code{last-nonmenu-event} to a suitable
|
|
1364 value around the call.
|
|
1365
|
|
1366 The return value of @code{map-y-or-n-p} is the number of objects acted on.
|
|
1367 @end defun
|
|
1368
|
434
|
1369 @node Reading a Password
|
|
1370 @section Reading a Password
|
|
1371 @cindex passwords, reading
|
|
1372
|
|
1373 To read a password to pass to another program, you can use the
|
|
1374 function @code{read-passwd}.
|
|
1375
|
|
1376 @defun read-passwd prompt &optional confirm default
|
|
1377 This function reads a password, prompting with @var{prompt}. It does
|
|
1378 not echo the password as the user types it; instead, it echoes @samp{.}
|
|
1379 for each character in the password.
|
|
1380
|
|
1381 The optional argument @var{confirm}, if non-@code{nil}, says to read the
|
|
1382 password twice and insist it must be the same both times. If it isn't
|
|
1383 the same, the user has to type it over and over until the last two
|
|
1384 times match.
|
|
1385
|
|
1386 The optional argument @var{default} specifies the default password to
|
|
1387 return if the user enters empty input. It is translated to @samp{.}
|
|
1388 and inserted in the minibuffer. If @var{default} is @code{nil}, then
|
|
1389 @code{read-passwd} returns the null string in that case.
|
|
1390 @end defun
|
|
1391
|
|
1392 @defopt passwd-invert-frame-when-keyboard-grabbed
|
|
1393 If non-nil swap the foreground and background colors of all faces while
|
|
1394 reading a password. Default values is @code{t} unless feature
|
|
1395 @code{infodock} is provided.
|
|
1396 @end defopt
|
|
1397
|
|
1398 @defopt passwd-echo
|
|
1399 This specifies the character echoed when typing a password. When nil,
|
|
1400 nothing is echoed.
|
|
1401 @end defopt
|
|
1402
|
428
|
1403 @node Minibuffer Misc
|
|
1404 @section Minibuffer Miscellany
|
|
1405
|
|
1406 This section describes some basic functions and variables related to
|
|
1407 minibuffers.
|
|
1408
|
|
1409 @deffn Command exit-minibuffer
|
|
1410 This command exits the active minibuffer. It is normally bound to
|
|
1411 keys in minibuffer local keymaps.
|
|
1412 @end deffn
|
|
1413
|
|
1414 @deffn Command self-insert-and-exit
|
|
1415 This command exits the active minibuffer after inserting the last
|
|
1416 character typed on the keyboard (found in @code{last-command-char};
|
|
1417 @pxref{Command Loop Info}).
|
|
1418 @end deffn
|
|
1419
|
|
1420 @deffn Command previous-history-element n
|
|
1421 This command replaces the minibuffer contents with the value of the
|
|
1422 @var{n}th previous (older) history element.
|
|
1423 @end deffn
|
|
1424
|
|
1425 @deffn Command next-history-element n
|
|
1426 This command replaces the minibuffer contents with the value of the
|
|
1427 @var{n}th more recent history element.
|
|
1428 @end deffn
|
|
1429
|
|
1430 @deffn Command previous-matching-history-element pattern
|
|
1431 This command replaces the minibuffer contents with the value of the
|
|
1432 previous (older) history element that matches @var{pattern} (a regular
|
|
1433 expression).
|
|
1434 @end deffn
|
|
1435
|
|
1436 @deffn Command next-matching-history-element pattern
|
|
1437 This command replaces the minibuffer contents with the value of the next
|
|
1438 (newer) history element that matches @var{pattern} (a regular
|
|
1439 expression).
|
|
1440 @end deffn
|
|
1441
|
|
1442 @defun minibuffer-prompt
|
|
1443 This function returns the prompt string of the currently active
|
|
1444 minibuffer. If no minibuffer is active, it returns @code{nil}.
|
|
1445 @end defun
|
|
1446
|
|
1447 @defun minibuffer-prompt-width
|
|
1448 This function returns the display width of the prompt string of the
|
|
1449 currently active minibuffer. If no minibuffer is active, it returns 0.
|
|
1450 @end defun
|
|
1451
|
|
1452 @defvar minibuffer-setup-hook
|
|
1453 This is a normal hook that is run whenever the minibuffer is entered.
|
|
1454 @xref{Hooks}.
|
|
1455 @end defvar
|
|
1456
|
|
1457 @defvar minibuffer-exit-hook
|
|
1458 This is a normal hook that is run whenever the minibuffer is exited.
|
|
1459 @xref{Hooks}.
|
|
1460 @end defvar
|
|
1461
|
|
1462 @defvar minibuffer-help-form
|
|
1463 The current value of this variable is used to rebind @code{help-form}
|
|
1464 locally inside the minibuffer (@pxref{Help Functions}).
|
|
1465 @end defvar
|
|
1466
|
|
1467 @defun active-minibuffer-window
|
|
1468 This function returns the currently active minibuffer window, or
|
|
1469 @code{nil} if none is currently active.
|
|
1470 @end defun
|
|
1471
|
|
1472 @defun minibuffer-window &optional frame
|
|
1473 This function returns the minibuffer window used for frame @var{frame}.
|
|
1474 If @var{frame} is @code{nil}, that stands for the current frame. Note
|
|
1475 that the minibuffer window used by a frame need not be part of that
|
|
1476 frame---a frame that has no minibuffer of its own necessarily uses some
|
|
1477 other frame's minibuffer window.
|
|
1478 @end defun
|
|
1479
|
|
1480 @c Emacs 19 feature
|
|
1481 @defun window-minibuffer-p window
|
|
1482 This function returns non-@code{nil} if @var{window} is a minibuffer window.
|
|
1483 @end defun
|
|
1484
|
|
1485 It is not correct to determine whether a given window is a minibuffer by
|
|
1486 comparing it with the result of @code{(minibuffer-window)}, because
|
|
1487 there can be more than one minibuffer window if there is more than one
|
|
1488 frame.
|
|
1489
|
|
1490 @defun minibuffer-window-active-p window
|
|
1491 This function returns non-@code{nil} if @var{window}, assumed to be
|
|
1492 a minibuffer window, is currently active.
|
|
1493 @end defun
|
|
1494
|
|
1495 @defvar minibuffer-scroll-window
|
|
1496 If the value of this variable is non-@code{nil}, it should be a window
|
|
1497 object. When the function @code{scroll-other-window} is called in the
|
|
1498 minibuffer, it scrolls this window.
|
|
1499 @end defvar
|
|
1500
|
|
1501 Finally, some functions and variables deal with recursive minibuffers
|
|
1502 (@pxref{Recursive Editing}):
|
|
1503
|
|
1504 @defun minibuffer-depth
|
|
1505 This function returns the current depth of activations of the
|
|
1506 minibuffer, a nonnegative integer. If no minibuffers are active, it
|
|
1507 returns zero.
|
|
1508 @end defun
|
|
1509
|
|
1510 @defopt enable-recursive-minibuffers
|
|
1511 If this variable is non-@code{nil}, you can invoke commands (such as
|
434
|
1512 @code{find-file}) that use minibuffers even while the minibuffer window
|
|
1513 is active. Such invocation produces a recursive editing level for a new
|
428
|
1514 minibuffer. The outer-level minibuffer is invisible while you are
|
|
1515 editing the inner one.
|
|
1516
|
|
1517 This variable only affects invoking the minibuffer while the
|
|
1518 minibuffer window is selected. If you switch windows while in the
|
|
1519 minibuffer, you can always invoke minibuffer commands while some other
|
|
1520 window is selected.
|
|
1521 @end defopt
|
|
1522
|
|
1523 @c Emacs 19 feature
|
|
1524 In FSF Emacs 19, if a command name has a property
|
|
1525 @code{enable-recursive-minibuffers} that is non-@code{nil}, then the
|
|
1526 command can use the minibuffer to read arguments even if it is invoked
|
|
1527 from the minibuffer. The minibuffer command
|
|
1528 @code{next-matching-history-element} (normally @kbd{M-s} in the
|
|
1529 minibuffer) uses this feature.
|
|
1530
|
|
1531 This is not implemented in XEmacs because it is a kludge. If you
|
|
1532 want to explicitly set the value of @code{enable-recursive-minibuffers}
|
|
1533 in this fashion, just use an evaluated interactive spec and bind
|
|
1534 @code{enable-recursive-minibuffers} while reading from the minibuffer.
|
|
1535 See the definition of @code{next-matching-history-element} in
|
434
|
1536 @file{lisp/minibuf.el}.
|