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