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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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444
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3 @c Copyright (C) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
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428
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4 @c See the file lispref.texi for copying conditions.
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5 @setfilename ../../info/text.info
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6 @node Text, Searching and Matching, Markers, Top
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7 @chapter Text
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8 @cindex text
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9
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10 This chapter describes the functions that deal with the text in a
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11 buffer. Most examine, insert, or delete text in the current buffer,
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12 often in the vicinity of point. Many are interactive. All the
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13 functions that change the text provide for undoing the changes
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14 (@pxref{Undo}).
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15
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16 Many text-related functions operate on a region of text defined by two
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17 buffer positions passed in arguments named @var{start} and @var{end}.
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18 These arguments should be either markers (@pxref{Markers}) or numeric
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19 character positions (@pxref{Positions}). The order of these arguments
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20 does not matter; it is all right for @var{start} to be the end of the
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21 region and @var{end} the beginning. For example, @code{(delete-region 1
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22 10)} and @code{(delete-region 10 1)} are equivalent. An
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23 @code{args-out-of-range} error is signaled if either @var{start} or
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24 @var{end} is outside the accessible portion of the buffer. In an
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25 interactive call, point and the mark are used for these arguments.
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26
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27 @cindex buffer contents
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28 Throughout this chapter, ``text'' refers to the characters in the
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29 buffer, together with their properties (when relevant).
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30
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31 @menu
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32 * Near Point:: Examining text in the vicinity of point.
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33 * Buffer Contents:: Examining text in a general fashion.
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34 * Comparing Text:: Comparing substrings of buffers.
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35 * Insertion:: Adding new text to a buffer.
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36 * Commands for Insertion:: User-level commands to insert text.
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37 * Deletion:: Removing text from a buffer.
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38 * User-Level Deletion:: User-level commands to delete text.
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39 * The Kill Ring:: Where removed text sometimes is saved for later use.
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40 * Undo:: Undoing changes to the text of a buffer.
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41 * Maintaining Undo:: How to enable and disable undo information.
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42 How to control how much information is kept.
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43 * Filling:: Functions for explicit filling.
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44 * Margins:: How to specify margins for filling commands.
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45 * Auto Filling:: How auto-fill mode is implemented to break lines.
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46 * Sorting:: Functions for sorting parts of the buffer.
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47 * Columns:: Computing horizontal positions, and using them.
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48 * Indentation:: Functions to insert or adjust indentation.
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49 * Case Changes:: Case conversion of parts of the buffer.
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50 * Text Properties:: Assigning Lisp property lists to text characters.
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51 * Substitution:: Replacing a given character wherever it appears.
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52 * Registers:: How registers are implemented. Accessing the text or
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53 position stored in a register.
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54 * Transposition:: Swapping two portions of a buffer.
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55 * Change Hooks:: Supplying functions to be run when text is changed.
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56 * Transformations:: MD5 and base64 support.
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57 @end menu
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58
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59 @node Near Point
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60 @section Examining Text Near Point
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61
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62 Many functions are provided to look at the characters around point.
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63 Several simple functions are described here. See also @code{looking-at}
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64 in @ref{Regexp Search}.
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65
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66 Many of these functions take an optional @var{buffer} argument.
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67 In all such cases, the current buffer will be used if this argument
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68 is omitted. (In FSF Emacs, and earlier versions of XEmacs, these
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69 functions usually did not have these optional @var{buffer} arguments
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70 and always operated on the current buffer.)
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71
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72
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434
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73 @defun char-after &optional position buffer
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74 This function returns the character in the buffer at (i.e.,
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75 immediately after) position @var{position}. If @var{position} is out of
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76 range for this purpose, either before the beginning of the buffer, or at
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77 or beyond the end, then the value is @code{nil}. The default for
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78 @var{position} is point. If optional argument @var{buffer} is
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79 @code{nil}, the current buffer is assumed.
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80
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81 In the following example, assume that the first character in the
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82 buffer is @samp{@@}:
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83
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84 @example
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85 @group
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86 (char-to-string (char-after 1))
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87 @result{} "@@"
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88 @end group
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89 @end example
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90 @end defun
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91
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434
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92 @defun char-before &optional position buffer
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93 This function returns the character in the current buffer immediately
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94 before position @var{position}. If @var{position} is out of range for
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95 this purpose, either at or before the beginning of the buffer, or beyond
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96 the end, then the value is @code{nil}. The default for
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97 @var{position} is point. If optional argument @var{buffer} is
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98 @code{nil}, the current buffer is assumed.
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99 @end defun
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100
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428
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101 @defun following-char &optional buffer
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102 This function returns the character following point in the buffer.
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103 This is similar to @code{(char-after (point))}. However, if point is at
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104 the end of the buffer, then the result of @code{following-char} is 0.
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105 If optional argument @var{buffer} is @code{nil}, the current buffer is
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106 assumed.
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107
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108 Remember that point is always between characters, and the terminal
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109 cursor normally appears over the character following point. Therefore,
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110 the character returned by @code{following-char} is the character the
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111 cursor is over.
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112
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113 In this example, point is between the @samp{a} and the @samp{c}.
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114
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115 @example
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116 @group
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117 ---------- Buffer: foo ----------
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118 Gentlemen may cry ``Pea@point{}ce! Peace!,''
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119 but there is no peace.
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120 ---------- Buffer: foo ----------
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121 @end group
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122
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123 @group
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124 (char-to-string (preceding-char))
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125 @result{} "a"
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126 (char-to-string (following-char))
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127 @result{} "c"
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128 @end group
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129 @end example
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130 @end defun
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131
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132 @defun preceding-char &optional buffer
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133 This function returns the character preceding point in the buffer.
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134 See above, under @code{following-char}, for an example. If
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135 point is at the beginning of the buffer, @code{preceding-char} returns
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136 0. If optional argument @var{buffer} is @code{nil}, the current buffer
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137 is assumed.
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138 @end defun
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139
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140 @defun bobp &optional buffer
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141 This function returns @code{t} if point is at the beginning of the
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142 buffer. If narrowing is in effect, this means the beginning of the
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143 accessible portion of the text. If optional argument @var{buffer} is
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144 @code{nil}, the current buffer is assumed. See also @code{point-min} in
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145 @ref{Point}.
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146 @end defun
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147
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148 @defun eobp &optional buffer
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149 This function returns @code{t} if point is at the end of the buffer.
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150 If narrowing is in effect, this means the end of accessible portion of
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151 the text. If optional argument @var{buffer} is @code{nil}, the current
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152 buffer is assumed. See also @code{point-max} in @xref{Point}.
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153 @end defun
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154
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155 @defun bolp &optional buffer
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156 This function returns @code{t} if point is at the beginning of a line.
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157 If optional argument @var{buffer} is @code{nil}, the current buffer is
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158 assumed. @xref{Text Lines}. The beginning of the buffer (or its
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159 accessible portion) always counts as the beginning of a line.
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160 @end defun
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161
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162 @defun eolp &optional buffer
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163 This function returns @code{t} if point is at the end of a line. The
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164 end of the buffer is always considered the end of a line. If optional
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165 argument @var{buffer} is @code{nil}, the current buffer is assumed.
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166 The end of the buffer (or of its accessible portion) is always considered
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167 the end of a line.
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168 @end defun
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169
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170 @node Buffer Contents
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171 @section Examining Buffer Contents
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172
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173 This section describes two functions that allow a Lisp program to
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174 convert any portion of the text in the buffer into a string.
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175
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176 @defun buffer-substring start end &optional buffer
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177 @defunx buffer-string start end &optional buffer
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178 These functions are equivalent and return a string containing a copy of
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179 the text of the region defined by positions @var{start} and @var{end} in
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180 the buffer. If the arguments are not positions in the accessible
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181 portion of the buffer, @code{buffer-substring} signals an
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182 @code{args-out-of-range} error. If optional argument @var{buffer} is
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183 @code{nil}, the current buffer is assumed.
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184
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185 @c XEmacs feature.
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186 If the region delineated by @var{start} and @var{end} contains
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187 duplicable extents, they will be remembered in the string.
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188 @xref{Duplicable Extents}.
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189
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190 It is not necessary for @var{start} to be less than @var{end}; the
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191 arguments can be given in either order. But most often the smaller
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192 argument is written first.
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193
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194 @example
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195 @group
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196 ---------- Buffer: foo ----------
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197 This is the contents of buffer foo
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198
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199 ---------- Buffer: foo ----------
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200 @end group
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201
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202 @group
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203 (buffer-substring 1 10)
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204 @result{} "This is t"
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205 @end group
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206 @group
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207 (buffer-substring (point-max) 10)
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208 @result{} "he contents of buffer foo
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209 "
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210 @end group
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211 @end example
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212 @end defun
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213
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214 @ignore
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215 @c `equal' in XEmacs does not compare text properties on strings
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216 @defun buffer-substring-without-properties start end
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217 This is like @code{buffer-substring}, except that it does not copy text
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218 properties, just the characters themselves. @xref{Text Properties}.
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219 Here's an example of using this function to get a word to look up in an
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220 alist:
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221
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222 @example
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223 (setq flammable
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224 (assoc (buffer-substring start end)
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225 '(("wood" . t) ("paper" . t)
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226 ("steel" . nil) ("asbestos" . nil))))
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227 @end example
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228
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229 If this were written using @code{buffer-substring} instead, it would not
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230 work reliably; any text properties that happened to be in the word
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231 copied from the buffer would make the comparisons fail.
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232 @end defun
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233 @end ignore
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234
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235 @node Comparing Text
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236 @section Comparing Text
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237 @cindex comparing buffer text
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238
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239 This function lets you compare portions of the text in a buffer, without
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240 copying them into strings first.
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241
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242 @defun compare-buffer-substrings buffer1 start1 end1 buffer2 start2 end2
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243 This function lets you compare two substrings of the same buffer or two
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244 different buffers. The first three arguments specify one substring,
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245 giving a buffer and two positions within the buffer. The last three
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246 arguments specify the other substring in the same way. You can use
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247 @code{nil} for @var{buffer1}, @var{buffer2}, or both to stand for the
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248 current buffer.
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249
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250 The value is negative if the first substring is less, positive if the
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251 first is greater, and zero if they are equal. The absolute value of
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252 the result is one plus the index of the first differing characters
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253 within the substrings.
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254
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255 This function ignores case when comparing characters
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256 if @code{case-fold-search} is non-@code{nil}. It always ignores
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257 text properties.
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258
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259 Suppose the current buffer contains the text @samp{foobarbar
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260 haha!rara!}; then in this example the two substrings are @samp{rbar }
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261 and @samp{rara!}. The value is 2 because the first substring is greater
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262 at the second character.
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263
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264 @example
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265 (compare-buffer-substring nil 6 11 nil 16 21)
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266 @result{} 2
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267 @end example
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268 @end defun
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269
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270 @node Insertion
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271 @section Inserting Text
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272 @cindex insertion of text
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273 @cindex text insertion
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274
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275 @dfn{Insertion} means adding new text to a buffer. The inserted text
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276 goes at point---between the character before point and the character
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277 after point.
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278
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279 Insertion relocates markers that point at positions after the
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280 insertion point, so that they stay with the surrounding text
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281 (@pxref{Markers}). When a marker points at the place of insertion,
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282 insertion normally doesn't relocate the marker, so that it points to the
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283 beginning of the inserted text; however, certain special functions such
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284 as @code{insert-before-markers} relocate such markers to point after the
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285 inserted text.
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286
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287 @cindex insertion before point
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288 @cindex before point, insertion
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289 Some insertion functions leave point before the inserted text, while
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290 other functions leave it after. We call the former insertion @dfn{after
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291 point} and the latter insertion @dfn{before point}.
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292
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293 @c XEmacs feature.
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294 If a string with non-@code{nil} extent data is inserted, the remembered
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295 extents will also be inserted. @xref{Duplicable Extents}.
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296
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297 Insertion functions signal an error if the current buffer is
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298 read-only.
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299
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300 These functions copy text characters from strings and buffers along
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301 with their properties. The inserted characters have exactly the same
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302 properties as the characters they were copied from. By contrast,
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303 characters specified as separate arguments, not part of a string or
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304 buffer, inherit their text properties from the neighboring text.
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305
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306 @defun insert &rest args
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307 This function inserts the strings and/or characters @var{args} into the
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308 current buffer, at point, moving point forward. In other words, it
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309 inserts the text before point. An error is signaled unless all
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310 @var{args} are either strings or characters. The value is @code{nil}.
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311 @end defun
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312
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313 @defun insert-before-markers &rest args
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314 This function inserts the strings and/or characters @var{args} into the
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315 current buffer, at point, moving point forward. An error is signaled
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316 unless all @var{args} are either strings or characters. The value is
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317 @code{nil}.
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318
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319 This function is unlike the other insertion functions in that it
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320 relocates markers initially pointing at the insertion point, to point
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321 after the inserted text.
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322 @end defun
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323
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324 @defun insert-string string &optional buffer
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325 This function inserts @var{string} into @var{buffer} before point.
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326 @var{buffer} defaults to the current buffer if omitted. This
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327 function is chiefly useful if you want to insert a string in
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328 a buffer other than the current one (otherwise you could just
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329 use @code{insert}).
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330 @end defun
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331
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444
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332 @defun insert-char character &optional count ignored buffer
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428
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333 This function inserts @var{count} instances of @var{character} into
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334 @var{buffer} before point. @var{count} must be a number, and
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444
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335 @var{character} must be a character.
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336
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337 If optional argument @var{buffer} is @code{nil}, the current buffer is
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338 assumed. (In FSF Emacs, the third argument is called @var{inherit} and
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339 refers to text properties. In XEmacs, it is always ignored.)
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340
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341 This function always returns @code{nil}.
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428
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342 @end defun
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343
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344 @defun insert-buffer-substring from-buffer-or-name &optional start end
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345 This function inserts a portion of buffer @var{from-buffer-or-name}
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346 (which must already exist) into the current buffer before point. The
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347 text inserted is the region from @var{start} and @var{end}. (These
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348 arguments default to the beginning and end of the accessible portion of
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349 that buffer.) This function returns @code{nil}.
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350
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351 In this example, the form is executed with buffer @samp{bar} as the
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352 current buffer. We assume that buffer @samp{bar} is initially empty.
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353
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354 @example
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355 @group
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356 ---------- Buffer: foo ----------
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357 We hold these truths to be self-evident, that all
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358 ---------- Buffer: foo ----------
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359 @end group
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360
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361 @group
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362 (insert-buffer-substring "foo" 1 20)
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363 @result{} nil
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364
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365 ---------- Buffer: bar ----------
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366 We hold these truth@point{}
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367 ---------- Buffer: bar ----------
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368 @end group
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369 @end example
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370 @end defun
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371
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372 @node Commands for Insertion
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373 @section User-Level Insertion Commands
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374
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375 This section describes higher-level commands for inserting text,
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376 commands intended primarily for the user but useful also in Lisp
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377 programs.
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378
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379 @deffn Command insert-buffer from-buffer-or-name
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380 This command inserts the entire contents of @var{from-buffer-or-name}
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381 (which must exist) into the current buffer after point. It leaves
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382 the mark after the inserted text. The value is @code{nil}.
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383 @end deffn
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384
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385 @deffn Command self-insert-command count
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386 @cindex character insertion
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387 @cindex self-insertion
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388 This command inserts the last character typed; it does so @var{count}
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389 times, before point, and returns @code{nil}. Most printing characters
|
|
|
390 are bound to this command. In routine use, @code{self-insert-command}
|
|
|
391 is the most frequently called function in XEmacs, but programs rarely use
|
|
|
392 it except to install it on a keymap.
|
|
|
393
|
|
|
394 In an interactive call, @var{count} is the numeric prefix argument.
|
|
|
395
|
|
|
396 This command calls @code{auto-fill-function} whenever that is
|
|
|
397 non-@code{nil} and the character inserted is a space or a newline
|
|
|
398 (@pxref{Auto Filling}).
|
|
|
399
|
|
|
400 @c Cross refs reworded to prevent overfull hbox. --rjc 15mar92
|
|
|
401 This command performs abbrev expansion if Abbrev mode is enabled and
|
|
|
402 the inserted character does not have word-constituent
|
|
|
403 syntax. (@xref{Abbrevs}, and @ref{Syntax Class Table}.)
|
|
|
404
|
|
|
405 This is also responsible for calling @code{blink-paren-function} when
|
|
|
406 the inserted character has close parenthesis syntax (@pxref{Blinking}).
|
|
|
407 @end deffn
|
|
|
408
|
|
444
|
409 @deffn Command newline &optional count
|
|
428
|
410 This command inserts newlines into the current buffer before point.
|
|
444
|
411 If @var{count} is supplied, that many newline characters
|
|
428
|
412 are inserted.
|
|
|
413
|
|
|
414 @cindex newline and Auto Fill mode
|
|
|
415 This function calls @code{auto-fill-function} if the current column
|
|
|
416 number is greater than the value of @code{fill-column} and
|
|
444
|
417 @var{count} is @code{nil}. Typically what
|
|
428
|
418 @code{auto-fill-function} does is insert a newline; thus, the overall
|
|
|
419 result in this case is to insert two newlines at different places: one
|
|
|
420 at point, and another earlier in the line. @code{newline} does not
|
|
444
|
421 auto-fill if @var{count} is non-@code{nil}.
|
|
428
|
422
|
|
|
423 This command indents to the left margin if that is not zero.
|
|
|
424 @xref{Margins}.
|
|
|
425
|
|
|
426 The value returned is @code{nil}. In an interactive call, @var{count}
|
|
|
427 is the numeric prefix argument.
|
|
|
428 @end deffn
|
|
|
429
|
|
|
430 @deffn Command split-line
|
|
|
431 This command splits the current line, moving the portion of the line
|
|
|
432 after point down vertically so that it is on the next line directly
|
|
|
433 below where it was before. Whitespace is inserted as needed at the
|
|
|
434 beginning of the lower line, using the @code{indent-to} function.
|
|
|
435 @code{split-line} returns the position of point.
|
|
|
436
|
|
|
437 Programs hardly ever use this function.
|
|
|
438 @end deffn
|
|
|
439
|
|
|
440 @defvar overwrite-mode
|
|
|
441 This variable controls whether overwrite mode is in effect: a
|
|
|
442 non-@code{nil} value enables the mode. It is automatically made
|
|
|
443 buffer-local when set in any fashion.
|
|
|
444 @end defvar
|
|
|
445
|
|
|
446 @node Deletion
|
|
|
447 @section Deleting Text
|
|
|
448
|
|
|
449 @cindex deletion vs killing
|
|
|
450 Deletion means removing part of the text in a buffer, without saving
|
|
|
451 it in the kill ring (@pxref{The Kill Ring}). Deleted text can't be
|
|
|
452 yanked, but can be reinserted using the undo mechanism (@pxref{Undo}).
|
|
|
453 Some deletion functions do save text in the kill ring in some special
|
|
|
454 cases.
|
|
|
455
|
|
|
456 All of the deletion functions operate on the current buffer, and all
|
|
|
457 return a value of @code{nil}.
|
|
|
458
|
|
444
|
459 @deffn Command erase-buffer &optional buffer
|
|
428
|
460 This function deletes the entire text of @var{buffer}, leaving it
|
|
|
461 empty. If the buffer is read-only, it signals a @code{buffer-read-only}
|
|
|
462 error. Otherwise, it deletes the text without asking for any
|
|
|
463 confirmation. It returns @code{nil}. @var{buffer} defaults to the
|
|
|
464 current buffer if omitted.
|
|
|
465
|
|
|
466 Normally, deleting a large amount of text from a buffer inhibits further
|
|
|
467 auto-saving of that buffer ``because it has shrunk''. However,
|
|
|
468 @code{erase-buffer} does not do this, the idea being that the future
|
|
|
469 text is not really related to the former text, and its size should not
|
|
|
470 be compared with that of the former text.
|
|
444
|
471 @end deffn
|
|
428
|
472
|
|
|
473 @deffn Command delete-region start end &optional buffer
|
|
|
474 This command deletes the text in @var{buffer} in the region defined by
|
|
|
475 @var{start} and @var{end}. The value is @code{nil}. If optional
|
|
|
476 argument @var{buffer} is @code{nil}, the current buffer is assumed.
|
|
|
477 @end deffn
|
|
|
478
|
|
446
|
479 @deffn Command delete-char &optional count killp
|
|
428
|
480 This command deletes @var{count} characters directly after point, or
|
|
446
|
481 before point if @var{count} is negative. @var{count} defaults to @code{1}.
|
|
|
482 If @var{killp} is non-@code{nil}, then it saves the deleted characters
|
|
|
483 in the kill ring.
|
|
428
|
484
|
|
|
485 In an interactive call, @var{count} is the numeric prefix argument, and
|
|
|
486 @var{killp} is the unprocessed prefix argument. Therefore, if a prefix
|
|
|
487 argument is supplied, the text is saved in the kill ring. If no prefix
|
|
|
488 argument is supplied, then one character is deleted, but not saved in
|
|
|
489 the kill ring.
|
|
|
490
|
|
|
491 The value returned is always @code{nil}.
|
|
|
492 @end deffn
|
|
|
493
|
|
446
|
494 @deffn Command delete-backward-char &optional count killp
|
|
428
|
495 @cindex delete previous char
|
|
|
496 This command deletes @var{count} characters directly before point, or
|
|
446
|
497 after point if @var{count} is negative. @var{count} defaults to 1.
|
|
|
498 If @var{killp} is non-@code{nil}, then it saves the deleted characters
|
|
|
499 in the kill ring.
|
|
428
|
500
|
|
|
501 In an interactive call, @var{count} is the numeric prefix argument, and
|
|
|
502 @var{killp} is the unprocessed prefix argument. Therefore, if a prefix
|
|
|
503 argument is supplied, the text is saved in the kill ring. If no prefix
|
|
|
504 argument is supplied, then one character is deleted, but not saved in
|
|
|
505 the kill ring.
|
|
|
506
|
|
|
507 The value returned is always @code{nil}.
|
|
|
508 @end deffn
|
|
|
509
|
|
|
510 @deffn Command backward-delete-char-untabify count &optional killp
|
|
|
511 @cindex tab deletion
|
|
|
512 This command deletes @var{count} characters backward, changing tabs
|
|
|
513 into spaces. When the next character to be deleted is a tab, it is
|
|
|
514 first replaced with the proper number of spaces to preserve alignment
|
|
|
515 and then one of those spaces is deleted instead of the tab. If
|
|
|
516 @var{killp} is non-@code{nil}, then the command saves the deleted
|
|
|
517 characters in the kill ring.
|
|
|
518
|
|
|
519 Conversion of tabs to spaces happens only if @var{count} is positive.
|
|
|
520 If it is negative, exactly @minus{}@var{count} characters after point
|
|
|
521 are deleted.
|
|
|
522
|
|
|
523 In an interactive call, @var{count} is the numeric prefix argument, and
|
|
|
524 @var{killp} is the unprocessed prefix argument. Therefore, if a prefix
|
|
|
525 argument is supplied, the text is saved in the kill ring. If no prefix
|
|
|
526 argument is supplied, then one character is deleted, but not saved in
|
|
|
527 the kill ring.
|
|
|
528
|
|
|
529 The value returned is always @code{nil}.
|
|
|
530 @end deffn
|
|
|
531
|
|
|
532 @node User-Level Deletion
|
|
|
533 @section User-Level Deletion Commands
|
|
|
534
|
|
|
535 This section describes higher-level commands for deleting text,
|
|
|
536 commands intended primarily for the user but useful also in Lisp
|
|
|
537 programs.
|
|
|
538
|
|
|
539 @deffn Command delete-horizontal-space
|
|
|
540 @cindex deleting whitespace
|
|
|
541 This function deletes all spaces and tabs around point. It returns
|
|
|
542 @code{nil}.
|
|
|
543
|
|
|
544 In the following examples, we call @code{delete-horizontal-space} four
|
|
|
545 times, once on each line, with point between the second and third
|
|
|
546 characters on the line each time.
|
|
|
547
|
|
|
548 @example
|
|
|
549 @group
|
|
|
550 ---------- Buffer: foo ----------
|
|
|
551 I @point{}thought
|
|
|
552 I @point{} thought
|
|
|
553 We@point{} thought
|
|
|
554 Yo@point{}u thought
|
|
|
555 ---------- Buffer: foo ----------
|
|
|
556 @end group
|
|
|
557
|
|
|
558 @group
|
|
|
559 (delete-horizontal-space) ; @r{Four times.}
|
|
|
560 @result{} nil
|
|
|
561
|
|
|
562 ---------- Buffer: foo ----------
|
|
|
563 Ithought
|
|
|
564 Ithought
|
|
|
565 Wethought
|
|
|
566 You thought
|
|
|
567 ---------- Buffer: foo ----------
|
|
|
568 @end group
|
|
|
569 @end example
|
|
|
570 @end deffn
|
|
|
571
|
|
444
|
572 @deffn Command delete-indentation &optional join-following-p
|
|
428
|
573 This function joins the line point is on to the previous line, deleting
|
|
|
574 any whitespace at the join and in some cases replacing it with one
|
|
|
575 space. If @var{join-following-p} is non-@code{nil},
|
|
|
576 @code{delete-indentation} joins this line to the following line
|
|
|
577 instead. The value is @code{nil}.
|
|
|
578
|
|
|
579 If there is a fill prefix, and the second of the lines being joined
|
|
|
580 starts with the prefix, then @code{delete-indentation} deletes the
|
|
|
581 fill prefix before joining the lines. @xref{Margins}.
|
|
|
582
|
|
|
583 In the example below, point is located on the line starting
|
|
|
584 @samp{events}, and it makes no difference if there are trailing spaces
|
|
|
585 in the preceding line.
|
|
|
586
|
|
|
587 @smallexample
|
|
|
588 @group
|
|
|
589 ---------- Buffer: foo ----------
|
|
|
590 When in the course of human
|
|
|
591 @point{} events, it becomes necessary
|
|
|
592 ---------- Buffer: foo ----------
|
|
|
593 @end group
|
|
|
594
|
|
|
595 (delete-indentation)
|
|
|
596 @result{} nil
|
|
|
597
|
|
|
598 @group
|
|
|
599 ---------- Buffer: foo ----------
|
|
|
600 When in the course of human@point{} events, it becomes necessary
|
|
|
601 ---------- Buffer: foo ----------
|
|
|
602 @end group
|
|
|
603 @end smallexample
|
|
|
604
|
|
|
605 After the lines are joined, the function @code{fixup-whitespace} is
|
|
|
606 responsible for deciding whether to leave a space at the junction.
|
|
|
607 @end deffn
|
|
|
608
|
|
444
|
609 @deffn Command fixup-whitespace
|
|
428
|
610 This function replaces all the white space surrounding point with either
|
|
|
611 one space or no space, according to the context. It returns @code{nil}.
|
|
|
612
|
|
|
613 At the beginning or end of a line, the appropriate amount of space is
|
|
|
614 none. Before a character with close parenthesis syntax, or after a
|
|
|
615 character with open parenthesis or expression-prefix syntax, no space is
|
|
|
616 also appropriate. Otherwise, one space is appropriate. @xref{Syntax
|
|
|
617 Class Table}.
|
|
|
618
|
|
|
619 In the example below, @code{fixup-whitespace} is called the first time
|
|
|
620 with point before the word @samp{spaces} in the first line. For the
|
|
|
621 second invocation, point is directly after the @samp{(}.
|
|
|
622
|
|
|
623 @smallexample
|
|
|
624 @group
|
|
|
625 ---------- Buffer: foo ----------
|
|
|
626 This has too many @point{}spaces
|
|
|
627 This has too many spaces at the start of (@point{} this list)
|
|
|
628 ---------- Buffer: foo ----------
|
|
|
629 @end group
|
|
|
630
|
|
|
631 @group
|
|
|
632 (fixup-whitespace)
|
|
|
633 @result{} nil
|
|
|
634 (fixup-whitespace)
|
|
|
635 @result{} nil
|
|
|
636 @end group
|
|
|
637
|
|
|
638 @group
|
|
|
639 ---------- Buffer: foo ----------
|
|
|
640 This has too many spaces
|
|
|
641 This has too many spaces at the start of (this list)
|
|
|
642 ---------- Buffer: foo ----------
|
|
|
643 @end group
|
|
|
644 @end smallexample
|
|
444
|
645 @end deffn
|
|
428
|
646
|
|
|
647 @deffn Command just-one-space
|
|
|
648 @comment !!SourceFile simple.el
|
|
|
649 This command replaces any spaces and tabs around point with a single
|
|
|
650 space. It returns @code{nil}.
|
|
|
651 @end deffn
|
|
|
652
|
|
|
653 @deffn Command delete-blank-lines
|
|
|
654 This function deletes blank lines surrounding point. If point is on a
|
|
|
655 blank line with one or more blank lines before or after it, then all but
|
|
|
656 one of them are deleted. If point is on an isolated blank line, then it
|
|
|
657 is deleted. If point is on a nonblank line, the command deletes all
|
|
|
658 blank lines following it.
|
|
|
659
|
|
|
660 A blank line is defined as a line containing only tabs and spaces.
|
|
|
661
|
|
|
662 @code{delete-blank-lines} returns @code{nil}.
|
|
|
663 @end deffn
|
|
|
664
|
|
|
665 @node The Kill Ring
|
|
|
666 @section The Kill Ring
|
|
|
667 @cindex kill ring
|
|
|
668
|
|
|
669 @dfn{Kill} functions delete text like the deletion functions, but save
|
|
|
670 it so that the user can reinsert it by @dfn{yanking}. Most of these
|
|
|
671 functions have @samp{kill-} in their name. By contrast, the functions
|
|
|
672 whose names start with @samp{delete-} normally do not save text for
|
|
|
673 yanking (though they can still be undone); these are ``deletion''
|
|
|
674 functions.
|
|
|
675
|
|
|
676 Most of the kill commands are primarily for interactive use, and are
|
|
|
677 not described here. What we do describe are the functions provided for
|
|
|
678 use in writing such commands. You can use these functions to write
|
|
|
679 commands for killing text. When you need to delete text for internal
|
|
|
680 purposes within a Lisp function, you should normally use deletion
|
|
|
681 functions, so as not to disturb the kill ring contents.
|
|
|
682 @xref{Deletion}.
|
|
|
683
|
|
|
684 Killed text is saved for later yanking in the @dfn{kill ring}. This
|
|
|
685 is a list that holds a number of recent kills, not just the last text
|
|
|
686 kill. We call this a ``ring'' because yanking treats it as having
|
|
|
687 elements in a cyclic order. The list is kept in the variable
|
|
|
688 @code{kill-ring}, and can be operated on with the usual functions for
|
|
|
689 lists; there are also specialized functions, described in this section,
|
|
|
690 that treat it as a ring.
|
|
|
691
|
|
|
692 Some people think this use of the word ``kill'' is unfortunate, since
|
|
|
693 it refers to operations that specifically @emph{do not} destroy the
|
|
|
694 entities ``killed''. This is in sharp contrast to ordinary life, in
|
|
|
695 which death is permanent and ``killed'' entities do not come back to
|
|
|
696 life. Therefore, other metaphors have been proposed. For example, the
|
|
|
697 term ``cut ring'' makes sense to people who, in pre-computer days, used
|
|
|
698 scissors and paste to cut up and rearrange manuscripts. However, it
|
|
|
699 would be difficult to change the terminology now.
|
|
|
700
|
|
|
701 @menu
|
|
|
702 * Kill Ring Concepts:: What text looks like in the kill ring.
|
|
|
703 * Kill Functions:: Functions that kill text.
|
|
|
704 * Yank Commands:: Commands that access the kill ring.
|
|
|
705 * Low-Level Kill Ring:: Functions and variables for kill ring access.
|
|
|
706 * Internals of Kill Ring:: Variables that hold kill-ring data.
|
|
|
707 @end menu
|
|
|
708
|
|
|
709 @node Kill Ring Concepts
|
|
|
710 @subsection Kill Ring Concepts
|
|
|
711
|
|
|
712 The kill ring records killed text as strings in a list, most recent
|
|
|
713 first. A short kill ring, for example, might look like this:
|
|
|
714
|
|
|
715 @example
|
|
|
716 ("some text" "a different piece of text" "even older text")
|
|
|
717 @end example
|
|
|
718
|
|
|
719 @noindent
|
|
|
720 When the list reaches @code{kill-ring-max} entries in length, adding a
|
|
|
721 new entry automatically deletes the last entry.
|
|
|
722
|
|
|
723 When kill commands are interwoven with other commands, each kill
|
|
|
724 command makes a new entry in the kill ring. Multiple kill commands in
|
|
|
725 succession build up a single entry in the kill ring, which would be
|
|
|
726 yanked as a unit; the second and subsequent consecutive kill commands
|
|
|
727 add text to the entry made by the first one.
|
|
|
728
|
|
|
729 For yanking, one entry in the kill ring is designated the ``front'' of
|
|
|
730 the ring. Some yank commands ``rotate'' the ring by designating a
|
|
|
731 different element as the ``front.'' But this virtual rotation doesn't
|
|
|
732 change the list itself---the most recent entry always comes first in the
|
|
|
733 list.
|
|
|
734
|
|
|
735 @node Kill Functions
|
|
|
736 @subsection Functions for Killing
|
|
|
737
|
|
|
738 @code{kill-region} is the usual subroutine for killing text. Any
|
|
|
739 command that calls this function is a ``kill command'' (and should
|
|
|
740 probably have @samp{kill} in its name). @code{kill-region} puts the
|
|
|
741 newly killed text in a new element at the beginning of the kill ring or
|
|
|
742 adds it to the most recent element. It uses the @code{last-command}
|
|
|
743 variable to determine whether the previous command was a kill command,
|
|
|
744 and if so appends the killed text to the most recent entry.
|
|
|
745
|
|
444
|
746 @deffn Command kill-region start end &optional verbose
|
|
428
|
747 This function kills the text in the region defined by @var{start} and
|
|
|
748 @var{end}. The text is deleted but saved in the kill ring, along with
|
|
|
749 its text properties. The value is always @code{nil}.
|
|
|
750
|
|
|
751 In an interactive call, @var{start} and @var{end} are point and
|
|
|
752 the mark.
|
|
|
753
|
|
|
754 @c Emacs 19 feature
|
|
|
755 If the buffer is read-only, @code{kill-region} modifies the kill ring
|
|
|
756 just the same, then signals an error without modifying the buffer. This
|
|
|
757 is convenient because it lets the user use all the kill commands to copy
|
|
|
758 text into the kill ring from a read-only buffer.
|
|
|
759 @end deffn
|
|
|
760
|
|
|
761 @deffn Command copy-region-as-kill start end
|
|
|
762 This command saves the region defined by @var{start} and @var{end} on
|
|
|
763 the kill ring (including text properties), but does not delete the text
|
|
|
764 from the buffer. It returns @code{nil}. It also indicates the extent
|
|
|
765 of the text copied by moving the cursor momentarily, or by displaying a
|
|
|
766 message in the echo area.
|
|
|
767
|
|
|
768 The command does not set @code{this-command} to @code{kill-region}, so a
|
|
|
769 subsequent kill command does not append to the same kill ring entry.
|
|
|
770
|
|
|
771 Don't call @code{copy-region-as-kill} in Lisp programs unless you aim to
|
|
|
772 support Emacs 18. For Emacs 19, it is better to use @code{kill-new} or
|
|
|
773 @code{kill-append} instead. @xref{Low-Level Kill Ring}.
|
|
|
774 @end deffn
|
|
|
775
|
|
|
776 @node Yank Commands
|
|
|
777 @subsection Functions for Yanking
|
|
|
778
|
|
|
779 @dfn{Yanking} means reinserting an entry of previously killed text
|
|
|
780 from the kill ring. The text properties are copied too.
|
|
|
781
|
|
|
782 @deffn Command yank &optional arg
|
|
|
783 @cindex inserting killed text
|
|
|
784 This command inserts before point the text in the first entry in the
|
|
|
785 kill ring. It positions the mark at the beginning of that text, and
|
|
|
786 point at the end.
|
|
|
787
|
|
|
788 If @var{arg} is a list (which occurs interactively when the user
|
|
|
789 types @kbd{C-u} with no digits), then @code{yank} inserts the text as
|
|
|
790 described above, but puts point before the yanked text and puts the mark
|
|
|
791 after it.
|
|
|
792
|
|
|
793 If @var{arg} is a number, then @code{yank} inserts the @var{arg}th most
|
|
|
794 recently killed text---the @var{arg}th element of the kill ring list.
|
|
|
795
|
|
|
796 @code{yank} does not alter the contents of the kill ring or rotate it.
|
|
|
797 It returns @code{nil}.
|
|
|
798 @end deffn
|
|
|
799
|
|
|
800 @deffn Command yank-pop arg
|
|
|
801 This command replaces the just-yanked entry from the kill ring with a
|
|
|
802 different entry from the kill ring.
|
|
|
803
|
|
|
804 This is allowed only immediately after a @code{yank} or another
|
|
|
805 @code{yank-pop}. At such a time, the region contains text that was just
|
|
|
806 inserted by yanking. @code{yank-pop} deletes that text and inserts in
|
|
|
807 its place a different piece of killed text. It does not add the deleted
|
|
|
808 text to the kill ring, since it is already in the kill ring somewhere.
|
|
|
809
|
|
|
810 If @var{arg} is @code{nil}, then the replacement text is the previous
|
|
|
811 element of the kill ring. If @var{arg} is numeric, the replacement is
|
|
|
812 the @var{arg}th previous kill. If @var{arg} is negative, a more recent
|
|
|
813 kill is the replacement.
|
|
|
814
|
|
|
815 The sequence of kills in the kill ring wraps around, so that after the
|
|
|
816 oldest one comes the newest one, and before the newest one goes the
|
|
|
817 oldest.
|
|
|
818
|
|
|
819 The value is always @code{nil}.
|
|
|
820 @end deffn
|
|
|
821
|
|
|
822 @node Low-Level Kill Ring
|
|
|
823 @subsection Low-Level Kill Ring
|
|
|
824
|
|
|
825 These functions and variables provide access to the kill ring at a lower
|
|
|
826 level, but still convenient for use in Lisp programs. They take care of
|
|
|
827 interaction with X Window selections. They do not exist in Emacs
|
|
|
828 version 18.
|
|
|
829
|
|
444
|
830 @defun current-kill count &optional do-not-move
|
|
428
|
831 The function @code{current-kill} rotates the yanking pointer which
|
|
444
|
832 designates the ``front'' of the kill ring by @var{count} places (from newer
|
|
428
|
833 kills to older ones), and returns the text at that place in the ring.
|
|
|
834
|
|
|
835 If the optional second argument @var{do-not-move} is non-@code{nil},
|
|
|
836 then @code{current-kill} doesn't alter the yanking pointer; it just
|
|
444
|
837 returns the @var{count}th kill, counting from the current yanking pointer.
|
|
|
838
|
|
|
839 If @var{count} is zero, indicating a request for the latest kill,
|
|
428
|
840 @code{current-kill} calls the value of
|
|
|
841 @code{interprogram-paste-function} (documented below) before consulting
|
|
|
842 the kill ring.
|
|
|
843 @end defun
|
|
|
844
|
|
444
|
845 @defun kill-new string &optional replace
|
|
|
846 This function makes the text @var{string} the latest entry in the kill
|
|
|
847 ring, and sets @code{kill-ring-yank-pointer} to point to it.
|
|
|
848
|
|
|
849 Normally, @var{string} is added to the front of the kill ring as a new
|
|
|
850 entry. However, if optional argument @var{replace} is non-@code{nil},
|
|
|
851 the entry previously at the front of the kill ring is discarded, and
|
|
|
852 @var{string} replaces it.
|
|
|
853
|
|
|
854 This function runs the functions on @code{kill-hooks}, and also invokes
|
|
|
855 the value of @code{interprogram-cut-function} (see below).
|
|
428
|
856 @end defun
|
|
|
857
|
|
|
858 @defun kill-append string before-p
|
|
|
859 This function appends the text @var{string} to the first entry in the
|
|
|
860 kill ring. Normally @var{string} goes at the end of the entry, but if
|
|
|
861 @var{before-p} is non-@code{nil}, it goes at the beginning. This
|
|
|
862 function also invokes the value of @code{interprogram-cut-function} (see
|
|
|
863 below).
|
|
|
864 @end defun
|
|
|
865
|
|
|
866 @defvar interprogram-paste-function
|
|
|
867 This variable provides a way of transferring killed text from other
|
|
|
868 programs, when you are using a window system. Its value should be
|
|
|
869 @code{nil} or a function of no arguments.
|
|
|
870
|
|
|
871 If the value is a function, @code{current-kill} calls it to get the
|
|
|
872 ``most recent kill''. If the function returns a non-@code{nil} value,
|
|
|
873 then that value is used as the ``most recent kill''. If it returns
|
|
|
874 @code{nil}, then the first element of @code{kill-ring} is used.
|
|
|
875
|
|
|
876 The normal use of this hook is to get the X server's primary selection
|
|
|
877 as the most recent kill, even if the selection belongs to another X
|
|
|
878 client. @xref{X Selections}.
|
|
|
879 @end defvar
|
|
|
880
|
|
|
881 @defvar interprogram-cut-function
|
|
|
882 This variable provides a way of communicating killed text to other
|
|
|
883 programs, when you are using a window system. Its value should be
|
|
|
884 @code{nil} or a function of one argument.
|
|
|
885
|
|
|
886 If the value is a function, @code{kill-new} and @code{kill-append} call
|
|
|
887 it with the new first element of the kill ring as an argument.
|
|
|
888
|
|
|
889 The normal use of this hook is to set the X server's primary selection
|
|
|
890 to the newly killed text.
|
|
|
891 @end defvar
|
|
|
892
|
|
|
893 @node Internals of Kill Ring
|
|
|
894 @subsection Internals of the Kill Ring
|
|
|
895
|
|
|
896 The variable @code{kill-ring} holds the kill ring contents, in the
|
|
|
897 form of a list of strings. The most recent kill is always at the front
|
|
444
|
898 of the list.
|
|
428
|
899
|
|
|
900 The @code{kill-ring-yank-pointer} variable points to a link in the
|
|
|
901 kill ring list, whose @sc{car} is the text to yank next. We say it
|
|
|
902 identifies the ``front'' of the ring. Moving
|
|
|
903 @code{kill-ring-yank-pointer} to a different link is called
|
|
|
904 @dfn{rotating the kill ring}. We call the kill ring a ``ring'' because
|
|
|
905 the functions that move the yank pointer wrap around from the end of the
|
|
|
906 list to the beginning, or vice-versa. Rotation of the kill ring is
|
|
|
907 virtual; it does not change the value of @code{kill-ring}.
|
|
|
908
|
|
|
909 Both @code{kill-ring} and @code{kill-ring-yank-pointer} are Lisp
|
|
|
910 variables whose values are normally lists. The word ``pointer'' in the
|
|
|
911 name of the @code{kill-ring-yank-pointer} indicates that the variable's
|
|
|
912 purpose is to identify one element of the list for use by the next yank
|
|
|
913 command.
|
|
|
914
|
|
|
915 The value of @code{kill-ring-yank-pointer} is always @code{eq} to one
|
|
|
916 of the links in the kill ring list. The element it identifies is the
|
|
|
917 @sc{car} of that link. Kill commands, which change the kill ring, also
|
|
|
918 set this variable to the value of @code{kill-ring}. The effect is to
|
|
|
919 rotate the ring so that the newly killed text is at the front.
|
|
|
920
|
|
|
921 Here is a diagram that shows the variable @code{kill-ring-yank-pointer}
|
|
|
922 pointing to the second entry in the kill ring @code{("some text" "a
|
|
444
|
923 different piece of text" "yet older text")}.
|
|
428
|
924
|
|
|
925 @example
|
|
|
926 @group
|
|
|
927 kill-ring kill-ring-yank-pointer
|
|
|
928 | |
|
|
|
929 | ___ ___ ---> ___ ___ ___ ___
|
|
|
930 --> |___|___|------> |___|___|--> |___|___|--> nil
|
|
444
|
931 | | |
|
|
|
932 | | |
|
|
|
933 | | -->"yet older text"
|
|
428
|
934 | |
|
|
444
|
935 | --> "a different piece of text"
|
|
428
|
936 |
|
|
|
937 --> "some text"
|
|
|
938 @end group
|
|
|
939 @end example
|
|
|
940
|
|
|
941 @noindent
|
|
|
942 This state of affairs might occur after @kbd{C-y} (@code{yank})
|
|
|
943 immediately followed by @kbd{M-y} (@code{yank-pop}).
|
|
|
944
|
|
|
945 @defvar kill-ring
|
|
|
946 This variable holds the list of killed text sequences, most recently
|
|
|
947 killed first.
|
|
|
948 @end defvar
|
|
|
949
|
|
|
950 @defvar kill-ring-yank-pointer
|
|
|
951 This variable's value indicates which element of the kill ring is at the
|
|
|
952 ``front'' of the ring for yanking. More precisely, the value is a tail
|
|
|
953 of the value of @code{kill-ring}, and its @sc{car} is the kill string
|
|
|
954 that @kbd{C-y} should yank.
|
|
|
955 @end defvar
|
|
|
956
|
|
|
957 @defopt kill-ring-max
|
|
|
958 The value of this variable is the maximum length to which the kill
|
|
|
959 ring can grow, before elements are thrown away at the end. The default
|
|
|
960 value for @code{kill-ring-max} is 30.
|
|
|
961 @end defopt
|
|
|
962
|
|
|
963 @node Undo
|
|
|
964 @section Undo
|
|
|
965 @cindex redo
|
|
|
966
|
|
|
967 Most buffers have an @dfn{undo list}, which records all changes made
|
|
|
968 to the buffer's text so that they can be undone. (The buffers that
|
|
|
969 don't have one are usually special-purpose buffers for which XEmacs
|
|
|
970 assumes that undoing is not useful.) All the primitives that modify the
|
|
|
971 text in the buffer automatically add elements to the front of the undo
|
|
|
972 list, which is in the variable @code{buffer-undo-list}.
|
|
|
973
|
|
|
974 @defvar buffer-undo-list
|
|
|
975 This variable's value is the undo list of the current buffer.
|
|
|
976 A value of @code{t} disables the recording of undo information.
|
|
|
977 @end defvar
|
|
|
978
|
|
|
979 Here are the kinds of elements an undo list can have:
|
|
|
980
|
|
|
981 @table @code
|
|
|
982 @item @var{integer}
|
|
|
983 This kind of element records a previous value of point. Ordinary cursor
|
|
|
984 motion does not get any sort of undo record, but deletion commands use
|
|
|
985 these entries to record where point was before the command.
|
|
|
986
|
|
444
|
987 @item (@var{start} . @var{end})
|
|
428
|
988 This kind of element indicates how to delete text that was inserted.
|
|
444
|
989 Upon insertion, the text occupied the range @var{start}--@var{end} in the
|
|
428
|
990 buffer.
|
|
|
991
|
|
|
992 @item (@var{text} . @var{position})
|
|
|
993 This kind of element indicates how to reinsert text that was deleted.
|
|
|
994 The deleted text itself is the string @var{text}. The place to
|
|
|
995 reinsert it is @code{(abs @var{position})}.
|
|
|
996
|
|
|
997 @item (t @var{high} . @var{low})
|
|
|
998 This kind of element indicates that an unmodified buffer became
|
|
|
999 modified. The elements @var{high} and @var{low} are two integers, each
|
|
|
1000 recording 16 bits of the visited file's modification time as of when it
|
|
|
1001 was previously visited or saved. @code{primitive-undo} uses those
|
|
|
1002 values to determine whether to mark the buffer as unmodified once again;
|
|
|
1003 it does so only if the file's modification time matches those numbers.
|
|
|
1004
|
|
444
|
1005 @item (nil @var{property} @var{value} @var{start} . @var{end})
|
|
428
|
1006 This kind of element records a change in a text property.
|
|
|
1007 Here's how you might undo the change:
|
|
|
1008
|
|
|
1009 @example
|
|
444
|
1010 (put-text-property @var{start} @var{end} @var{property} @var{value})
|
|
428
|
1011 @end example
|
|
|
1012
|
|
|
1013 @item @var{position}
|
|
|
1014 This element indicates where point was at an earlier time. Undoing this
|
|
|
1015 element sets point to @var{position}. Deletion normally creates an
|
|
|
1016 element of this kind as well as a reinsertion element.
|
|
|
1017
|
|
|
1018 @item nil
|
|
|
1019 This element is a boundary. The elements between two boundaries are
|
|
|
1020 called a @dfn{change group}; normally, each change group corresponds to
|
|
|
1021 one keyboard command, and undo commands normally undo an entire group as
|
|
|
1022 a unit.
|
|
|
1023 @end table
|
|
|
1024
|
|
|
1025 @defun undo-boundary
|
|
|
1026 This function places a boundary element in the undo list. The undo
|
|
|
1027 command stops at such a boundary, and successive undo commands undo
|
|
|
1028 to earlier and earlier boundaries. This function returns @code{nil}.
|
|
|
1029
|
|
|
1030 The editor command loop automatically creates an undo boundary before
|
|
|
1031 each key sequence is executed. Thus, each undo normally undoes the
|
|
|
1032 effects of one command. Self-inserting input characters are an
|
|
|
1033 exception. The command loop makes a boundary for the first such
|
|
|
1034 character; the next 19 consecutive self-inserting input characters do
|
|
|
1035 not make boundaries, and then the 20th does, and so on as long as
|
|
|
1036 self-inserting characters continue.
|
|
|
1037
|
|
|
1038 All buffer modifications add a boundary whenever the previous undoable
|
|
|
1039 change was made in some other buffer. This way, a command that modifies
|
|
|
1040 several buffers makes a boundary in each buffer it changes.
|
|
|
1041
|
|
|
1042 Calling this function explicitly is useful for splitting the effects of
|
|
|
1043 a command into more than one unit. For example, @code{query-replace}
|
|
|
1044 calls @code{undo-boundary} after each replacement, so that the user can
|
|
|
1045 undo individual replacements one by one.
|
|
|
1046 @end defun
|
|
|
1047
|
|
|
1048 @defun primitive-undo count list
|
|
|
1049 This is the basic function for undoing elements of an undo list.
|
|
|
1050 It undoes the first @var{count} elements of @var{list}, returning
|
|
|
1051 the rest of @var{list}. You could write this function in Lisp,
|
|
|
1052 but it is convenient to have it in C.
|
|
|
1053
|
|
|
1054 @code{primitive-undo} adds elements to the buffer's undo list when it
|
|
|
1055 changes the buffer. Undo commands avoid confusion by saving the undo
|
|
|
1056 list value at the beginning of a sequence of undo operations. Then the
|
|
|
1057 undo operations use and update the saved value. The new elements added
|
|
|
1058 by undoing are not part of this saved value, so they don't interfere with
|
|
|
1059 continuing to undo.
|
|
|
1060 @end defun
|
|
|
1061
|
|
|
1062 @node Maintaining Undo
|
|
|
1063 @section Maintaining Undo Lists
|
|
|
1064
|
|
|
1065 This section describes how to enable and disable undo information for
|
|
|
1066 a given buffer. It also explains how the undo list is truncated
|
|
|
1067 automatically so it doesn't get too big.
|
|
|
1068
|
|
|
1069 Recording of undo information in a newly created buffer is normally
|
|
|
1070 enabled to start with; but if the buffer name starts with a space, the
|
|
|
1071 undo recording is initially disabled. You can explicitly enable or
|
|
|
1072 disable undo recording with the following two functions, or by setting
|
|
|
1073 @code{buffer-undo-list} yourself.
|
|
|
1074
|
|
|
1075 @deffn Command buffer-enable-undo &optional buffer-or-name
|
|
|
1076 This command enables recording undo information for buffer
|
|
|
1077 @var{buffer-or-name}, so that subsequent changes can be undone. If no
|
|
|
1078 argument is supplied, then the current buffer is used. This function
|
|
|
1079 does nothing if undo recording is already enabled in the buffer. It
|
|
|
1080 returns @code{nil}.
|
|
|
1081
|
|
|
1082 In an interactive call, @var{buffer-or-name} is the current buffer.
|
|
|
1083 You cannot specify any other buffer.
|
|
|
1084 @end deffn
|
|
|
1085
|
|
444
|
1086 @deffn Command buffer-disable-undo &optional buffer
|
|
|
1087 @deffnx Command buffer-flush-undo &optional buffer
|
|
428
|
1088 @cindex disable undo
|
|
|
1089 This function discards the undo list of @var{buffer}, and disables
|
|
|
1090 further recording of undo information. As a result, it is no longer
|
|
|
1091 possible to undo either previous changes or any subsequent changes. If
|
|
|
1092 the undo list of @var{buffer} is already disabled, this function
|
|
|
1093 has no effect.
|
|
|
1094
|
|
|
1095 This function returns @code{nil}. It cannot be called interactively.
|
|
|
1096
|
|
|
1097 The name @code{buffer-flush-undo} is not considered obsolete, but the
|
|
|
1098 preferred name @code{buffer-disable-undo} is new as of Emacs versions
|
|
|
1099 19.
|
|
444
|
1100 @end deffn
|
|
428
|
1101
|
|
|
1102 As editing continues, undo lists get longer and longer. To prevent
|
|
|
1103 them from using up all available memory space, garbage collection trims
|
|
|
1104 them back to size limits you can set. (For this purpose, the ``size''
|
|
|
1105 of an undo list measures the cons cells that make up the list, plus the
|
|
|
1106 strings of deleted text.) Two variables control the range of acceptable
|
|
|
1107 sizes: @code{undo-limit} and @code{undo-strong-limit}.
|
|
|
1108
|
|
|
1109 @defvar undo-limit
|
|
|
1110 This is the soft limit for the acceptable size of an undo list. The
|
|
|
1111 change group at which this size is exceeded is the last one kept.
|
|
|
1112 @end defvar
|
|
|
1113
|
|
|
1114 @defvar undo-strong-limit
|
|
|
1115 This is the upper limit for the acceptable size of an undo list. The
|
|
|
1116 change group at which this size is exceeded is discarded itself (along
|
|
|
1117 with all older change groups). There is one exception: the very latest
|
|
|
1118 change group is never discarded no matter how big it is.
|
|
|
1119 @end defvar
|
|
|
1120
|
|
|
1121 @node Filling
|
|
|
1122 @section Filling
|
|
|
1123 @cindex filling, explicit
|
|
|
1124
|
|
|
1125 @dfn{Filling} means adjusting the lengths of lines (by moving the line
|
|
|
1126 breaks) so that they are nearly (but no greater than) a specified
|
|
|
1127 maximum width. Additionally, lines can be @dfn{justified}, which means
|
|
|
1128 inserting spaces to make the left and/or right margins line up
|
|
|
1129 precisely. The width is controlled by the variable @code{fill-column}.
|
|
|
1130 For ease of reading, lines should be no longer than 70 or so columns.
|
|
|
1131
|
|
|
1132 You can use Auto Fill mode (@pxref{Auto Filling}) to fill text
|
|
|
1133 automatically as you insert it, but changes to existing text may leave
|
|
|
1134 it improperly filled. Then you must fill the text explicitly.
|
|
|
1135
|
|
|
1136 Most of the commands in this section return values that are not
|
|
|
1137 meaningful. All the functions that do filling take note of the current
|
|
|
1138 left margin, current right margin, and current justification style
|
|
|
1139 (@pxref{Margins}). If the current justification style is
|
|
|
1140 @code{none}, the filling functions don't actually do anything.
|
|
|
1141
|
|
|
1142 Several of the filling functions have an argument @var{justify}.
|
|
|
1143 If it is non-@code{nil}, that requests some kind of justification. It
|
|
|
1144 can be @code{left}, @code{right}, @code{full}, or @code{center}, to
|
|
|
1145 request a specific style of justification. If it is @code{t}, that
|
|
|
1146 means to use the current justification style for this part of the text
|
|
|
1147 (see @code{current-justification}, below).
|
|
|
1148
|
|
|
1149 When you call the filling functions interactively, using a prefix
|
|
|
1150 argument implies the value @code{full} for @var{justify}.
|
|
|
1151
|
|
|
1152 @deffn Command fill-paragraph justify
|
|
|
1153 @cindex filling a paragraph
|
|
|
1154 This command fills the paragraph at or after point. If
|
|
|
1155 @var{justify} is non-@code{nil}, each line is justified as well.
|
|
|
1156 It uses the ordinary paragraph motion commands to find paragraph
|
|
|
1157 boundaries. @xref{Paragraphs,,, xemacs, The XEmacs User's Manual}.
|
|
|
1158 @end deffn
|
|
|
1159
|
|
|
1160 @deffn Command fill-region start end &optional justify
|
|
|
1161 This command fills each of the paragraphs in the region from @var{start}
|
|
|
1162 to @var{end}. It justifies as well if @var{justify} is
|
|
|
1163 non-@code{nil}.
|
|
|
1164
|
|
|
1165 The variable @code{paragraph-separate} controls how to distinguish
|
|
|
1166 paragraphs. @xref{Standard Regexps}.
|
|
|
1167 @end deffn
|
|
|
1168
|
|
|
1169 @deffn Command fill-individual-paragraphs start end &optional justify mail-flag
|
|
|
1170 This command fills each paragraph in the region according to its
|
|
|
1171 individual fill prefix. Thus, if the lines of a paragraph were indented
|
|
|
1172 with spaces, the filled paragraph will remain indented in the same
|
|
|
1173 fashion.
|
|
|
1174
|
|
|
1175 The first two arguments, @var{start} and @var{end}, are the beginning
|
|
|
1176 and end of the region to be filled. The third and fourth arguments,
|
|
|
1177 @var{justify} and @var{mail-flag}, are optional. If
|
|
|
1178 @var{justify} is non-@code{nil}, the paragraphs are justified as
|
|
|
1179 well as filled. If @var{mail-flag} is non-@code{nil}, it means the
|
|
|
1180 function is operating on a mail message and therefore should not fill
|
|
|
1181 the header lines.
|
|
|
1182
|
|
|
1183 Ordinarily, @code{fill-individual-paragraphs} regards each change in
|
|
|
1184 indentation as starting a new paragraph. If
|
|
|
1185 @code{fill-individual-varying-indent} is non-@code{nil}, then only
|
|
|
1186 separator lines separate paragraphs. That mode can handle indented
|
|
|
1187 paragraphs with additional indentation on the first line.
|
|
|
1188 @end deffn
|
|
|
1189
|
|
|
1190 @defopt fill-individual-varying-indent
|
|
|
1191 This variable alters the action of @code{fill-individual-paragraphs} as
|
|
|
1192 described above.
|
|
|
1193 @end defopt
|
|
|
1194
|
|
|
1195 @deffn Command fill-region-as-paragraph start end &optional justify
|
|
|
1196 This command considers a region of text as a paragraph and fills it. If
|
|
|
1197 the region was made up of many paragraphs, the blank lines between
|
|
|
1198 paragraphs are removed. This function justifies as well as filling when
|
|
|
1199 @var{justify} is non-@code{nil}.
|
|
|
1200
|
|
|
1201 In an interactive call, any prefix argument requests justification.
|
|
|
1202
|
|
|
1203 In Adaptive Fill mode, which is enabled by default,
|
|
|
1204 @code{fill-region-as-paragraph} on an indented paragraph when there is
|
|
|
1205 no fill prefix uses the indentation of the second line of the paragraph
|
|
|
1206 as the fill prefix.
|
|
|
1207 @end deffn
|
|
|
1208
|
|
|
1209 @deffn Command justify-current-line how eop nosqueeze
|
|
|
1210 This command inserts spaces between the words of the current line so
|
|
|
1211 that the line ends exactly at @code{fill-column}. It returns
|
|
|
1212 @code{nil}.
|
|
|
1213
|
|
|
1214 The argument @var{how}, if non-@code{nil} specifies explicitly the style
|
|
|
1215 of justification. It can be @code{left}, @code{right}, @code{full},
|
|
|
1216 @code{center}, or @code{none}. If it is @code{t}, that means to do
|
|
|
1217 follow specified justification style (see @code{current-justification},
|
|
|
1218 below). @code{nil} means to do full justification.
|
|
|
1219
|
|
|
1220 If @var{eop} is non-@code{nil}, that means do left-justification when
|
|
|
1221 @code{current-justification} specifies full justification. This is used
|
|
|
1222 for the last line of a paragraph; even if the paragraph as a whole is
|
|
|
1223 fully justified, the last line should not be.
|
|
|
1224
|
|
|
1225 If @var{nosqueeze} is non-@code{nil}, that means do not change interior
|
|
|
1226 whitespace.
|
|
|
1227 @end deffn
|
|
|
1228
|
|
|
1229 @defopt default-justification
|
|
|
1230 This variable's value specifies the style of justification to use for
|
|
|
1231 text that doesn't specify a style with a text property. The possible
|
|
|
1232 values are @code{left}, @code{right}, @code{full}, @code{center}, or
|
|
|
1233 @code{none}. The default value is @code{left}.
|
|
|
1234 @end defopt
|
|
|
1235
|
|
|
1236 @defun current-justification
|
|
|
1237 This function returns the proper justification style to use for filling
|
|
|
1238 the text around point.
|
|
|
1239 @end defun
|
|
|
1240
|
|
|
1241 @defvar fill-paragraph-function
|
|
|
1242 This variable provides a way for major modes to override the filling of
|
|
|
1243 paragraphs. If the value is non-@code{nil}, @code{fill-paragraph} calls
|
|
|
1244 this function to do the work. If the function returns a non-@code{nil}
|
|
|
1245 value, @code{fill-paragraph} assumes the job is done, and immediately
|
|
|
1246 returns that value.
|
|
|
1247
|
|
|
1248 The usual use of this feature is to fill comments in programming
|
|
|
1249 language modes. If the function needs to fill a paragraph in the usual
|
|
|
1250 way, it can do so as follows:
|
|
|
1251
|
|
|
1252 @example
|
|
|
1253 (let ((fill-paragraph-function nil))
|
|
|
1254 (fill-paragraph arg))
|
|
|
1255 @end example
|
|
|
1256 @end defvar
|
|
|
1257
|
|
|
1258 @defvar use-hard-newlines
|
|
|
1259 If this variable is non-@code{nil}, the filling functions do not delete
|
|
|
1260 newlines that have the @code{hard} text property. These ``hard
|
|
|
1261 newlines'' act as paragraph separators.
|
|
|
1262 @end defvar
|
|
|
1263
|
|
|
1264 @node Margins
|
|
|
1265 @section Margins for Filling
|
|
|
1266
|
|
|
1267 @defopt fill-prefix
|
|
|
1268 This variable specifies a string of text that appears at the beginning
|
|
|
1269 of normal text lines and should be disregarded when filling them. Any
|
|
|
1270 line that fails to start with the fill prefix is considered the start of
|
|
|
1271 a paragraph; so is any line that starts with the fill prefix followed by
|
|
|
1272 additional whitespace. Lines that start with the fill prefix but no
|
|
|
1273 additional whitespace are ordinary text lines that can be filled
|
|
|
1274 together. The resulting filled lines also start with the fill prefix.
|
|
|
1275
|
|
|
1276 The fill prefix follows the left margin whitespace, if any.
|
|
|
1277 @end defopt
|
|
|
1278
|
|
|
1279 @defopt fill-column
|
|
|
1280 This buffer-local variable specifies the maximum width of filled
|
|
|
1281 lines. Its value should be an integer, which is a number of columns.
|
|
|
1282 All the filling, justification and centering commands are affected by
|
|
|
1283 this variable, including Auto Fill mode (@pxref{Auto Filling}).
|
|
|
1284
|
|
|
1285 As a practical matter, if you are writing text for other people to
|
|
|
1286 read, you should set @code{fill-column} to no more than 70. Otherwise
|
|
|
1287 the line will be too long for people to read comfortably, and this can
|
|
|
1288 make the text seem clumsy.
|
|
|
1289 @end defopt
|
|
|
1290
|
|
|
1291 @defvar default-fill-column
|
|
|
1292 The value of this variable is the default value for @code{fill-column} in
|
|
|
1293 buffers that do not override it. This is the same as
|
|
|
1294 @code{(default-value 'fill-column)}.
|
|
|
1295
|
|
|
1296 The default value for @code{default-fill-column} is 70.
|
|
|
1297 @end defvar
|
|
|
1298
|
|
|
1299 @deffn Command set-left-margin from to margin
|
|
|
1300 This sets the @code{left-margin} property on the text from @var{from} to
|
|
|
1301 @var{to} to the value @var{margin}. If Auto Fill mode is enabled, this
|
|
|
1302 command also refills the region to fit the new margin.
|
|
|
1303 @end deffn
|
|
|
1304
|
|
|
1305 @deffn Command set-right-margin from to margin
|
|
|
1306 This sets the @code{right-margin} property on the text from @var{from}
|
|
|
1307 to @var{to} to the value @var{margin}. If Auto Fill mode is enabled,
|
|
|
1308 this command also refills the region to fit the new margin.
|
|
|
1309 @end deffn
|
|
|
1310
|
|
|
1311 @defun current-left-margin
|
|
|
1312 This function returns the proper left margin value to use for filling
|
|
|
1313 the text around point. The value is the sum of the @code{left-margin}
|
|
|
1314 property of the character at the start of the current line (or zero if
|
|
|
1315 none), and the value of the variable @code{left-margin}.
|
|
|
1316 @end defun
|
|
|
1317
|
|
|
1318 @defun current-fill-column
|
|
|
1319 This function returns the proper fill column value to use for filling
|
|
|
1320 the text around point. The value is the value of the @code{fill-column}
|
|
|
1321 variable, minus the value of the @code{right-margin} property of the
|
|
|
1322 character after point.
|
|
|
1323 @end defun
|
|
|
1324
|
|
|
1325 @deffn Command move-to-left-margin &optional n force
|
|
|
1326 This function moves point to the left margin of the current line. The
|
|
|
1327 column moved to is determined by calling the function
|
|
|
1328 @code{current-left-margin}. If the argument @var{n} is non-@code{nil},
|
|
|
1329 @code{move-to-left-margin} moves forward @var{n}@minus{}1 lines first.
|
|
|
1330
|
|
|
1331 If @var{force} is non-@code{nil}, that says to fix the line's
|
|
|
1332 indentation if that doesn't match the left margin value.
|
|
|
1333 @end deffn
|
|
|
1334
|
|
444
|
1335 @defun delete-to-left-margin &optional from to
|
|
428
|
1336 This function removes left margin indentation from the text
|
|
|
1337 between @var{from} and @var{to}. The amount of indentation
|
|
|
1338 to delete is determined by calling @code{current-left-margin}.
|
|
|
1339 In no case does this function delete non-whitespace.
|
|
444
|
1340
|
|
|
1341 The arguments @var{from} and @var{to} are optional; the default is the
|
|
|
1342 whole buffer.
|
|
428
|
1343 @end defun
|
|
|
1344
|
|
|
1345 @defun indent-to-left-margin
|
|
|
1346 This is the default @code{indent-line-function}, used in Fundamental
|
|
|
1347 mode, Text mode, etc. Its effect is to adjust the indentation at the
|
|
|
1348 beginning of the current line to the value specified by the variable
|
|
|
1349 @code{left-margin}. This may involve either inserting or deleting
|
|
|
1350 whitespace.
|
|
|
1351 @end defun
|
|
|
1352
|
|
|
1353 @defvar left-margin
|
|
|
1354 This variable specifies the base left margin column. In Fundamental
|
|
|
1355 mode, @key{LFD} indents to this column. This variable automatically
|
|
|
1356 becomes buffer-local when set in any fashion.
|
|
|
1357 @end defvar
|
|
|
1358
|
|
|
1359 @node Auto Filling
|
|
|
1360 @section Auto Filling
|
|
|
1361 @cindex filling, automatic
|
|
|
1362 @cindex Auto Fill mode
|
|
|
1363
|
|
|
1364 Auto Fill mode is a minor mode that fills lines automatically as text
|
|
|
1365 is inserted. This section describes the hook used by Auto Fill mode.
|
|
|
1366 For a description of functions that you can call explicitly to fill and
|
|
|
1367 justify existing text, see @ref{Filling}.
|
|
|
1368
|
|
|
1369 Auto Fill mode also enables the functions that change the margins and
|
|
|
1370 justification style to refill portions of the text. @xref{Margins}.
|
|
|
1371
|
|
|
1372 @defvar auto-fill-function
|
|
|
1373 The value of this variable should be a function (of no arguments) to be
|
|
|
1374 called after self-inserting a space or a newline. It may be @code{nil},
|
|
|
1375 in which case nothing special is done in that case.
|
|
|
1376
|
|
|
1377 The value of @code{auto-fill-function} is @code{do-auto-fill} when
|
|
|
1378 Auto-Fill mode is enabled. That is a function whose sole purpose is to
|
|
|
1379 implement the usual strategy for breaking a line.
|
|
|
1380
|
|
|
1381 @quotation
|
|
|
1382 In older Emacs versions, this variable was named @code{auto-fill-hook},
|
|
|
1383 but since it is not called with the standard convention for hooks, it
|
|
|
1384 was renamed to @code{auto-fill-function} in version 19.
|
|
|
1385 @end quotation
|
|
|
1386 @end defvar
|
|
|
1387
|
|
|
1388 @node Sorting
|
|
|
1389 @section Sorting Text
|
|
|
1390 @cindex sorting text
|
|
|
1391
|
|
|
1392 The sorting functions described in this section all rearrange text in
|
|
|
1393 a buffer. This is in contrast to the function @code{sort}, which
|
|
|
1394 rearranges the order of the elements of a list (@pxref{Rearrangement}).
|
|
|
1395 The values returned by these functions are not meaningful.
|
|
|
1396
|
|
|
1397 @defun sort-subr reverse nextrecfun endrecfun &optional startkeyfun endkeyfun
|
|
|
1398 This function is the general text-sorting routine that divides a buffer
|
|
|
1399 into records and sorts them. Most of the commands in this section use
|
|
|
1400 this function.
|
|
|
1401
|
|
|
1402 To understand how @code{sort-subr} works, consider the whole accessible
|
|
|
1403 portion of the buffer as being divided into disjoint pieces called
|
|
|
1404 @dfn{sort records}. The records may or may not be contiguous; they may
|
|
|
1405 not overlap. A portion of each sort record (perhaps all of it) is
|
|
|
1406 designated as the sort key. Sorting rearranges the records in order by
|
|
|
1407 their sort keys.
|
|
|
1408
|
|
|
1409 Usually, the records are rearranged in order of ascending sort key.
|
|
|
1410 If the first argument to the @code{sort-subr} function, @var{reverse},
|
|
|
1411 is non-@code{nil}, the sort records are rearranged in order of
|
|
|
1412 descending sort key.
|
|
|
1413
|
|
|
1414 The next four arguments to @code{sort-subr} are functions that are
|
|
|
1415 called to move point across a sort record. They are called many times
|
|
|
1416 from within @code{sort-subr}.
|
|
|
1417
|
|
|
1418 @enumerate
|
|
|
1419 @item
|
|
|
1420 @var{nextrecfun} is called with point at the end of a record. This
|
|
|
1421 function moves point to the start of the next record. The first record
|
|
|
1422 is assumed to start at the position of point when @code{sort-subr} is
|
|
|
1423 called. Therefore, you should usually move point to the beginning of
|
|
|
1424 the buffer before calling @code{sort-subr}.
|
|
|
1425
|
|
|
1426 This function can indicate there are no more sort records by leaving
|
|
|
1427 point at the end of the buffer.
|
|
|
1428
|
|
|
1429 @item
|
|
|
1430 @var{endrecfun} is called with point within a record. It moves point to
|
|
|
1431 the end of the record.
|
|
|
1432
|
|
|
1433 @item
|
|
|
1434 @var{startkeyfun} is called to move point from the start of a record to
|
|
|
1435 the start of the sort key. This argument is optional; if it is omitted,
|
|
|
1436 the whole record is the sort key. If supplied, the function should
|
|
|
1437 either return a non-@code{nil} value to be used as the sort key, or
|
|
|
1438 return @code{nil} to indicate that the sort key is in the buffer
|
|
|
1439 starting at point. In the latter case, @var{endkeyfun} is called to
|
|
|
1440 find the end of the sort key.
|
|
|
1441
|
|
|
1442 @item
|
|
|
1443 @var{endkeyfun} is called to move point from the start of the sort key
|
|
|
1444 to the end of the sort key. This argument is optional. If
|
|
|
1445 @var{startkeyfun} returns @code{nil} and this argument is omitted (or
|
|
|
1446 @code{nil}), then the sort key extends to the end of the record. There
|
|
|
1447 is no need for @var{endkeyfun} if @var{startkeyfun} returns a
|
|
|
1448 non-@code{nil} value.
|
|
|
1449 @end enumerate
|
|
|
1450
|
|
|
1451 As an example of @code{sort-subr}, here is the complete function
|
|
|
1452 definition for @code{sort-lines}:
|
|
|
1453
|
|
|
1454 @example
|
|
|
1455 @group
|
|
|
1456 ;; @r{Note that the first two lines of doc string}
|
|
|
1457 ;; @r{are effectively one line when viewed by a user.}
|
|
444
|
1458 (defun sort-lines (reverse start end)
|
|
428
|
1459 "Sort lines in region alphabetically.
|
|
|
1460 Called from a program, there are three arguments:
|
|
|
1461 @end group
|
|
|
1462 @group
|
|
|
1463 REVERSE (non-nil means reverse order),
|
|
444
|
1464 and START and END (the region to sort)."
|
|
428
|
1465 (interactive "P\nr")
|
|
|
1466 (save-restriction
|
|
444
|
1467 (narrow-to-region start end)
|
|
428
|
1468 (goto-char (point-min))
|
|
|
1469 (sort-subr reverse
|
|
|
1470 'forward-line
|
|
|
1471 'end-of-line)))
|
|
|
1472 @end group
|
|
|
1473 @end example
|
|
|
1474
|
|
|
1475 Here @code{forward-line} moves point to the start of the next record,
|
|
|
1476 and @code{end-of-line} moves point to the end of record. We do not pass
|
|
|
1477 the arguments @var{startkeyfun} and @var{endkeyfun}, because the entire
|
|
|
1478 record is used as the sort key.
|
|
|
1479
|
|
|
1480 The @code{sort-paragraphs} function is very much the same, except that
|
|
|
1481 its @code{sort-subr} call looks like this:
|
|
|
1482
|
|
|
1483 @example
|
|
|
1484 @group
|
|
|
1485 (sort-subr reverse
|
|
444
|
1486 (function
|
|
|
1487 (lambda ()
|
|
428
|
1488 (skip-chars-forward "\n \t\f")))
|
|
|
1489 'forward-paragraph)
|
|
|
1490 @end group
|
|
|
1491 @end example
|
|
|
1492 @end defun
|
|
|
1493
|
|
|
1494 @deffn Command sort-regexp-fields reverse record-regexp key-regexp start end
|
|
|
1495 This command sorts the region between @var{start} and @var{end}
|
|
|
1496 alphabetically as specified by @var{record-regexp} and @var{key-regexp}.
|
|
|
1497 If @var{reverse} is a negative integer, then sorting is in reverse
|
|
|
1498 order.
|
|
|
1499
|
|
|
1500 Alphabetical sorting means that two sort keys are compared by
|
|
|
1501 comparing the first characters of each, the second characters of each,
|
|
|
1502 and so on. If a mismatch is found, it means that the sort keys are
|
|
|
1503 unequal; the sort key whose character is less at the point of first
|
|
|
1504 mismatch is the lesser sort key. The individual characters are compared
|
|
|
1505 according to their numerical values. Since Emacs uses the @sc{ascii}
|
|
|
1506 character set, the ordering in that set determines alphabetical order.
|
|
|
1507 @c version 19 change
|
|
|
1508
|
|
|
1509 The value of the @var{record-regexp} argument specifies how to divide
|
|
|
1510 the buffer into sort records. At the end of each record, a search is
|
|
|
1511 done for this regular expression, and the text that matches it is the
|
|
|
1512 next record. For example, the regular expression @samp{^.+$}, which
|
|
|
1513 matches lines with at least one character besides a newline, would make
|
|
|
1514 each such line into a sort record. @xref{Regular Expressions}, for a
|
|
|
1515 description of the syntax and meaning of regular expressions.
|
|
|
1516
|
|
|
1517 The value of the @var{key-regexp} argument specifies what part of each
|
|
|
1518 record is the sort key. The @var{key-regexp} could match the whole
|
|
|
1519 record, or only a part. In the latter case, the rest of the record has
|
|
|
1520 no effect on the sorted order of records, but it is carried along when
|
|
|
1521 the record moves to its new position.
|
|
|
1522
|
|
|
1523 The @var{key-regexp} argument can refer to the text matched by a
|
|
|
1524 subexpression of @var{record-regexp}, or it can be a regular expression
|
|
|
1525 on its own.
|
|
|
1526
|
|
|
1527 If @var{key-regexp} is:
|
|
|
1528
|
|
|
1529 @table @asis
|
|
|
1530 @item @samp{\@var{digit}}
|
|
|
1531 then the text matched by the @var{digit}th @samp{\(...\)} parenthesis
|
|
|
1532 grouping in @var{record-regexp} is the sort key.
|
|
|
1533
|
|
|
1534 @item @samp{\&}
|
|
|
1535 then the whole record is the sort key.
|
|
|
1536
|
|
|
1537 @item a regular expression
|
|
|
1538 then @code{sort-regexp-fields} searches for a match for the regular
|
|
|
1539 expression within the record. If such a match is found, it is the sort
|
|
|
1540 key. If there is no match for @var{key-regexp} within a record then
|
|
|
1541 that record is ignored, which means its position in the buffer is not
|
|
|
1542 changed. (The other records may move around it.)
|
|
|
1543 @end table
|
|
|
1544
|
|
|
1545 For example, if you plan to sort all the lines in the region by the
|
|
|
1546 first word on each line starting with the letter @samp{f}, you should
|
|
|
1547 set @var{record-regexp} to @samp{^.*$} and set @var{key-regexp} to
|
|
|
1548 @samp{\<f\w*\>}. The resulting expression looks like this:
|
|
|
1549
|
|
|
1550 @example
|
|
|
1551 @group
|
|
|
1552 (sort-regexp-fields nil "^.*$" "\\<f\\w*\\>"
|
|
|
1553 (region-beginning)
|
|
|
1554 (region-end))
|
|
|
1555 @end group
|
|
|
1556 @end example
|
|
|
1557
|
|
|
1558 If you call @code{sort-regexp-fields} interactively, it prompts for
|
|
|
1559 @var{record-regexp} and @var{key-regexp} in the minibuffer.
|
|
|
1560 @end deffn
|
|
|
1561
|
|
|
1562 @deffn Command sort-lines reverse start end
|
|
|
1563 This command alphabetically sorts lines in the region between
|
|
|
1564 @var{start} and @var{end}. If @var{reverse} is non-@code{nil}, the sort
|
|
|
1565 is in reverse order.
|
|
|
1566 @end deffn
|
|
|
1567
|
|
|
1568 @deffn Command sort-paragraphs reverse start end
|
|
|
1569 This command alphabetically sorts paragraphs in the region between
|
|
|
1570 @var{start} and @var{end}. If @var{reverse} is non-@code{nil}, the sort
|
|
|
1571 is in reverse order.
|
|
|
1572 @end deffn
|
|
|
1573
|
|
|
1574 @deffn Command sort-pages reverse start end
|
|
|
1575 This command alphabetically sorts pages in the region between
|
|
|
1576 @var{start} and @var{end}. If @var{reverse} is non-@code{nil}, the sort
|
|
|
1577 is in reverse order.
|
|
|
1578 @end deffn
|
|
|
1579
|
|
|
1580 @deffn Command sort-fields field start end
|
|
|
1581 This command sorts lines in the region between @var{start} and
|
|
|
1582 @var{end}, comparing them alphabetically by the @var{field}th field
|
|
|
1583 of each line. Fields are separated by whitespace and numbered starting
|
|
|
1584 from 1. If @var{field} is negative, sorting is by the
|
|
|
1585 @w{@minus{}@var{field}th} field from the end of the line. This command
|
|
|
1586 is useful for sorting tables.
|
|
|
1587 @end deffn
|
|
|
1588
|
|
|
1589 @deffn Command sort-numeric-fields field start end
|
|
|
1590 This command sorts lines in the region between @var{start} and
|
|
|
1591 @var{end}, comparing them numerically by the @var{field}th field of each
|
|
|
1592 line. The specified field must contain a number in each line of the
|
|
|
1593 region. Fields are separated by whitespace and numbered starting from
|
|
|
1594 1. If @var{field} is negative, sorting is by the
|
|
|
1595 @w{@minus{}@var{field}th} field from the end of the line. This command
|
|
|
1596 is useful for sorting tables.
|
|
|
1597 @end deffn
|
|
|
1598
|
|
444
|
1599 @deffn Command sort-columns reverse &optional start end
|
|
|
1600 This command sorts the lines in the region between @var{start} and
|
|
428
|
1601 @var{end}, comparing them alphabetically by a certain range of columns.
|
|
444
|
1602 The column positions of @var{start} and @var{end} bound the range of
|
|
428
|
1603 columns to sort on.
|
|
|
1604
|
|
|
1605 If @var{reverse} is non-@code{nil}, the sort is in reverse order.
|
|
|
1606
|
|
|
1607 One unusual thing about this command is that the entire line
|
|
444
|
1608 containing position @var{start}, and the entire line containing position
|
|
428
|
1609 @var{end}, are included in the region sorted.
|
|
|
1610
|
|
|
1611 Note that @code{sort-columns} uses the @code{sort} utility program,
|
|
|
1612 and so cannot work properly on text containing tab characters. Use
|
|
|
1613 @kbd{M-x @code{untabify}} to convert tabs to spaces before sorting.
|
|
|
1614 @end deffn
|
|
|
1615
|
|
|
1616 @node Columns
|
|
|
1617 @comment node-name, next, previous, up
|
|
|
1618 @section Counting Columns
|
|
|
1619 @cindex columns
|
|
|
1620 @cindex counting columns
|
|
|
1621 @cindex horizontal position
|
|
|
1622
|
|
|
1623 The column functions convert between a character position (counting
|
|
|
1624 characters from the beginning of the buffer) and a column position
|
|
|
1625 (counting screen characters from the beginning of a line).
|
|
|
1626
|
|
|
1627 A character counts according to the number of columns it occupies on
|
|
|
1628 the screen. This means control characters count as occupying 2 or 4
|
|
|
1629 columns, depending upon the value of @code{ctl-arrow}, and tabs count as
|
|
|
1630 occupying a number of columns that depends on the value of
|
|
|
1631 @code{tab-width} and on the column where the tab begins. @xref{Usual Display}.
|
|
|
1632
|
|
|
1633 Column number computations ignore the width of the window and the
|
|
|
1634 amount of horizontal scrolling. Consequently, a column value can be
|
|
|
1635 arbitrarily high. The first (or leftmost) column is numbered 0.
|
|
|
1636
|
|
444
|
1637 @defun current-column &optional buffer
|
|
428
|
1638 This function returns the horizontal position of point, measured in
|
|
444
|
1639 columns, counting from 0 at the left margin.
|
|
|
1640
|
|
|
1641 This is calculated by adding together the widths of all the displayed
|
|
|
1642 representations of the character between the start of the previous line
|
|
|
1643 and point. (e.g. control characters will have a width of 2 or 4, tabs
|
|
|
1644 will have a variable width.)
|
|
|
1645
|
|
|
1646 Ignores the finite width of frame displaying the buffer, which means
|
|
|
1647 that this function may return values greater than
|
|
|
1648 @code{(frame-width)}.
|
|
|
1649
|
|
|
1650 Whether the line is visible (if @code{selective-display} is t) has no effect;
|
|
|
1651 however, ^M is treated as end of line when @code{selective-display} is t.
|
|
|
1652
|
|
|
1653 If @var{buffer} is nil, the current buffer is assumed.
|
|
428
|
1654
|
|
|
1655 For an example of using @code{current-column}, see the description of
|
|
|
1656 @code{count-lines} in @ref{Text Lines}.
|
|
|
1657 @end defun
|
|
|
1658
|
|
444
|
1659 @defun move-to-column column &optional force buffer
|
|
428
|
1660 This function moves point to @var{column} in the current line. The
|
|
|
1661 calculation of @var{column} takes into account the widths of the
|
|
|
1662 displayed representations of the characters between the start of the
|
|
|
1663 line and point.
|
|
|
1664
|
|
|
1665 If column @var{column} is beyond the end of the line, point moves to the
|
|
|
1666 end of the line. If @var{column} is negative, point moves to the
|
|
|
1667 beginning of the line.
|
|
|
1668
|
|
|
1669 If it is impossible to move to column @var{column} because that is in
|
|
|
1670 the middle of a multicolumn character such as a tab, point moves to the
|
|
|
1671 end of that character. However, if @var{force} is non-@code{nil}, and
|
|
|
1672 @var{column} is in the middle of a tab, then @code{move-to-column}
|
|
|
1673 converts the tab into spaces so that it can move precisely to column
|
|
|
1674 @var{column}. Other multicolumn characters can cause anomalies despite
|
|
|
1675 @var{force}, since there is no way to split them.
|
|
|
1676
|
|
|
1677 The argument @var{force} also has an effect if the line isn't long
|
|
444
|
1678 enough to reach column @var{column}; in that case, unless the value of
|
|
|
1679 @var{force} is the special value @code{coerce}, it says to add
|
|
428
|
1680 whitespace at the end of the line to reach that column.
|
|
|
1681
|
|
444
|
1682 If @var{column} is not a non-negative integer, an error is signaled.
|
|
428
|
1683
|
|
|
1684 The return value is the column number actually moved to.
|
|
|
1685 @end defun
|
|
|
1686
|
|
|
1687 @node Indentation
|
|
|
1688 @section Indentation
|
|
|
1689 @cindex indentation
|
|
|
1690
|
|
|
1691 The indentation functions are used to examine, move to, and change
|
|
|
1692 whitespace that is at the beginning of a line. Some of the functions
|
|
|
1693 can also change whitespace elsewhere on a line. Columns and indentation
|
|
|
1694 count from zero at the left margin.
|
|
|
1695
|
|
|
1696 @menu
|
|
|
1697 * Primitive Indent:: Functions used to count and insert indentation.
|
|
|
1698 * Mode-Specific Indent:: Customize indentation for different modes.
|
|
|
1699 * Region Indent:: Indent all the lines in a region.
|
|
|
1700 * Relative Indent:: Indent the current line based on previous lines.
|
|
|
1701 * Indent Tabs:: Adjustable, typewriter-like tab stops.
|
|
|
1702 * Motion by Indent:: Move to first non-blank character.
|
|
|
1703 @end menu
|
|
|
1704
|
|
|
1705 @node Primitive Indent
|
|
|
1706 @subsection Indentation Primitives
|
|
|
1707
|
|
|
1708 This section describes the primitive functions used to count and
|
|
|
1709 insert indentation. The functions in the following sections use these
|
|
|
1710 primitives.
|
|
|
1711
|
|
444
|
1712 @defun current-indentation &optional buffer
|
|
428
|
1713 @comment !!Type Primitive Function
|
|
|
1714 @comment !!SourceFile indent.c
|
|
|
1715 This function returns the indentation of the current line, which is
|
|
|
1716 the horizontal position of the first nonblank character. If the
|
|
|
1717 contents are entirely blank, then this is the horizontal position of the
|
|
|
1718 end of the line.
|
|
|
1719 @end defun
|
|
|
1720
|
|
444
|
1721 @deffn Command indent-to column &optional minimum buffer
|
|
428
|
1722 @comment !!Type Primitive Function
|
|
|
1723 @comment !!SourceFile indent.c
|
|
|
1724 This function indents from point with tabs and spaces until @var{column}
|
|
|
1725 is reached. If @var{minimum} is specified and non-@code{nil}, then at
|
|
|
1726 least that many spaces are inserted even if this requires going beyond
|
|
|
1727 @var{column}. Otherwise the function does nothing if point is already
|
|
|
1728 beyond @var{column}. The value is the column at which the inserted
|
|
444
|
1729 indentation ends. If @var{buffer} is @code{nil}, the current buffer is assumed.
|
|
428
|
1730 @end deffn
|
|
|
1731
|
|
|
1732 @defopt indent-tabs-mode
|
|
|
1733 @comment !!SourceFile indent.c
|
|
|
1734 If this variable is non-@code{nil}, indentation functions can insert
|
|
|
1735 tabs as well as spaces. Otherwise, they insert only spaces. Setting
|
|
|
1736 this variable automatically makes it local to the current buffer.
|
|
|
1737 @end defopt
|
|
|
1738
|
|
|
1739 @node Mode-Specific Indent
|
|
|
1740 @subsection Indentation Controlled by Major Mode
|
|
|
1741
|
|
|
1742 An important function of each major mode is to customize the @key{TAB}
|
|
|
1743 key to indent properly for the language being edited. This section
|
|
|
1744 describes the mechanism of the @key{TAB} key and how to control it.
|
|
|
1745 The functions in this section return unpredictable values.
|
|
|
1746
|
|
|
1747 @defvar indent-line-function
|
|
|
1748 This variable's value is the function to be used by @key{TAB} (and
|
|
|
1749 various commands) to indent the current line. The command
|
|
|
1750 @code{indent-according-to-mode} does no more than call this function.
|
|
|
1751
|
|
|
1752 In Lisp mode, the value is the symbol @code{lisp-indent-line}; in C
|
|
|
1753 mode, @code{c-indent-line}; in Fortran mode, @code{fortran-indent-line}.
|
|
|
1754 In Fundamental mode, Text mode, and many other modes with no standard
|
|
|
1755 for indentation, the value is @code{indent-to-left-margin} (which is the
|
|
|
1756 default value).
|
|
|
1757 @end defvar
|
|
|
1758
|
|
|
1759 @deffn Command indent-according-to-mode
|
|
|
1760 This command calls the function in @code{indent-line-function} to
|
|
|
1761 indent the current line in a way appropriate for the current major mode.
|
|
|
1762 @end deffn
|
|
|
1763
|
|
444
|
1764 @deffn Command indent-for-tab-command &optional prefix-arg
|
|
428
|
1765 This command calls the function in @code{indent-line-function} to indent
|
|
|
1766 the current line; except that if that function is
|
|
|
1767 @code{indent-to-left-margin}, it calls @code{insert-tab} instead. (That
|
|
|
1768 is a trivial command that inserts a tab character.)
|
|
|
1769 @end deffn
|
|
|
1770
|
|
|
1771 @deffn Command newline-and-indent
|
|
|
1772 @comment !!SourceFile simple.el
|
|
|
1773 This function inserts a newline, then indents the new line (the one
|
|
|
1774 following the newline just inserted) according to the major mode.
|
|
|
1775
|
|
|
1776 It does indentation by calling the current @code{indent-line-function}.
|
|
|
1777 In programming language modes, this is the same thing @key{TAB} does,
|
|
|
1778 but in some text modes, where @key{TAB} inserts a tab,
|
|
|
1779 @code{newline-and-indent} indents to the column specified by
|
|
|
1780 @code{left-margin}.
|
|
|
1781 @end deffn
|
|
|
1782
|
|
|
1783 @deffn Command reindent-then-newline-and-indent
|
|
|
1784 @comment !!SourceFile simple.el
|
|
|
1785 This command reindents the current line, inserts a newline at point,
|
|
|
1786 and then reindents the new line (the one following the newline just
|
|
|
1787 inserted).
|
|
|
1788
|
|
|
1789 This command does indentation on both lines according to the current
|
|
|
1790 major mode, by calling the current value of @code{indent-line-function}.
|
|
|
1791 In programming language modes, this is the same thing @key{TAB} does,
|
|
|
1792 but in some text modes, where @key{TAB} inserts a tab,
|
|
|
1793 @code{reindent-then-newline-and-indent} indents to the column specified
|
|
|
1794 by @code{left-margin}.
|
|
|
1795 @end deffn
|
|
|
1796
|
|
|
1797 @node Region Indent
|
|
|
1798 @subsection Indenting an Entire Region
|
|
|
1799
|
|
|
1800 This section describes commands that indent all the lines in the
|
|
|
1801 region. They return unpredictable values.
|
|
|
1802
|
|
|
1803 @deffn Command indent-region start end to-column
|
|
|
1804 This command indents each nonblank line starting between @var{start}
|
|
|
1805 (inclusive) and @var{end} (exclusive). If @var{to-column} is
|
|
|
1806 @code{nil}, @code{indent-region} indents each nonblank line by calling
|
|
|
1807 the current mode's indentation function, the value of
|
|
|
1808 @code{indent-line-function}.
|
|
|
1809
|
|
|
1810 If @var{to-column} is non-@code{nil}, it should be an integer
|
|
|
1811 specifying the number of columns of indentation; then this function
|
|
|
1812 gives each line exactly that much indentation, by either adding or
|
|
|
1813 deleting whitespace.
|
|
|
1814
|
|
|
1815 If there is a fill prefix, @code{indent-region} indents each line
|
|
|
1816 by making it start with the fill prefix.
|
|
|
1817 @end deffn
|
|
|
1818
|
|
|
1819 @defvar indent-region-function
|
|
|
1820 The value of this variable is a function that can be used by
|
|
|
1821 @code{indent-region} as a short cut. You should design the function so
|
|
|
1822 that it will produce the same results as indenting the lines of the
|
|
|
1823 region one by one, but presumably faster.
|
|
|
1824
|
|
|
1825 If the value is @code{nil}, there is no short cut, and
|
|
|
1826 @code{indent-region} actually works line by line.
|
|
|
1827
|
|
|
1828 A short-cut function is useful in modes such as C mode and Lisp mode,
|
|
|
1829 where the @code{indent-line-function} must scan from the beginning of
|
|
|
1830 the function definition: applying it to each line would be quadratic in
|
|
|
1831 time. The short cut can update the scan information as it moves through
|
|
|
1832 the lines indenting them; this takes linear time. In a mode where
|
|
|
1833 indenting a line individually is fast, there is no need for a short cut.
|
|
|
1834
|
|
|
1835 @code{indent-region} with a non-@code{nil} argument @var{to-column} has
|
|
|
1836 a different meaning and does not use this variable.
|
|
|
1837 @end defvar
|
|
|
1838
|
|
|
1839 @deffn Command indent-rigidly start end count
|
|
|
1840 @comment !!SourceFile indent.el
|
|
|
1841 This command indents all lines starting between @var{start}
|
|
|
1842 (inclusive) and @var{end} (exclusive) sideways by @var{count} columns.
|
|
|
1843 This ``preserves the shape'' of the affected region, moving it as a
|
|
|
1844 rigid unit. Consequently, this command is useful not only for indenting
|
|
|
1845 regions of unindented text, but also for indenting regions of formatted
|
|
|
1846 code.
|
|
|
1847
|
|
|
1848 For example, if @var{count} is 3, this command adds 3 columns of
|
|
|
1849 indentation to each of the lines beginning in the region specified.
|
|
|
1850
|
|
|
1851 In Mail mode, @kbd{C-c C-y} (@code{mail-yank-original}) uses
|
|
|
1852 @code{indent-rigidly} to indent the text copied from the message being
|
|
|
1853 replied to.
|
|
|
1854 @end deffn
|
|
|
1855
|
|
444
|
1856 @deffn Command indent-code-rigidly start end columns &optional nochange-regexp
|
|
428
|
1857 This is like @code{indent-rigidly}, except that it doesn't alter lines
|
|
|
1858 that start within strings or comments.
|
|
|
1859
|
|
|
1860 In addition, it doesn't alter a line if @var{nochange-regexp} matches at
|
|
|
1861 the beginning of the line (if @var{nochange-regexp} is non-@code{nil}).
|
|
444
|
1862 @end deffn
|
|
428
|
1863
|
|
|
1864 @node Relative Indent
|
|
|
1865 @subsection Indentation Relative to Previous Lines
|
|
|
1866
|
|
|
1867 This section describes two commands that indent the current line
|
|
|
1868 based on the contents of previous lines.
|
|
|
1869
|
|
|
1870 @deffn Command indent-relative &optional unindented-ok
|
|
|
1871 This command inserts whitespace at point, extending to the same
|
|
|
1872 column as the next @dfn{indent point} of the previous nonblank line. An
|
|
|
1873 indent point is a non-whitespace character following whitespace. The
|
|
|
1874 next indent point is the first one at a column greater than the current
|
|
|
1875 column of point. For example, if point is underneath and to the left of
|
|
|
1876 the first non-blank character of a line of text, it moves to that column
|
|
|
1877 by inserting whitespace.
|
|
|
1878
|
|
|
1879 If the previous nonblank line has no next indent point (i.e., none at a
|
|
|
1880 great enough column position), @code{indent-relative} either does
|
|
|
1881 nothing (if @var{unindented-ok} is non-@code{nil}) or calls
|
|
|
1882 @code{tab-to-tab-stop}. Thus, if point is underneath and to the right
|
|
|
1883 of the last column of a short line of text, this command ordinarily
|
|
|
1884 moves point to the next tab stop by inserting whitespace.
|
|
|
1885
|
|
|
1886 The return value of @code{indent-relative} is unpredictable.
|
|
|
1887
|
|
|
1888 In the following example, point is at the beginning of the second
|
|
|
1889 line:
|
|
|
1890
|
|
|
1891 @example
|
|
|
1892 @group
|
|
|
1893 This line is indented twelve spaces.
|
|
|
1894 @point{}The quick brown fox jumped.
|
|
|
1895 @end group
|
|
|
1896 @end example
|
|
|
1897
|
|
|
1898 @noindent
|
|
|
1899 Evaluation of the expression @code{(indent-relative nil)} produces the
|
|
|
1900 following:
|
|
|
1901
|
|
|
1902 @example
|
|
|
1903 @group
|
|
|
1904 This line is indented twelve spaces.
|
|
|
1905 @point{}The quick brown fox jumped.
|
|
|
1906 @end group
|
|
|
1907 @end example
|
|
|
1908
|
|
|
1909 In this example, point is between the @samp{m} and @samp{p} of
|
|
|
1910 @samp{jumped}:
|
|
|
1911
|
|
|
1912 @example
|
|
|
1913 @group
|
|
|
1914 This line is indented twelve spaces.
|
|
|
1915 The quick brown fox jum@point{}ped.
|
|
|
1916 @end group
|
|
|
1917 @end example
|
|
|
1918
|
|
|
1919 @noindent
|
|
|
1920 Evaluation of the expression @code{(indent-relative nil)} produces the
|
|
|
1921 following:
|
|
|
1922
|
|
|
1923 @example
|
|
|
1924 @group
|
|
|
1925 This line is indented twelve spaces.
|
|
|
1926 The quick brown fox jum @point{}ped.
|
|
|
1927 @end group
|
|
|
1928 @end example
|
|
|
1929 @end deffn
|
|
|
1930
|
|
|
1931 @deffn Command indent-relative-maybe
|
|
|
1932 @comment !!SourceFile indent.el
|
|
|
1933 This command indents the current line like the previous nonblank line.
|
|
|
1934 It calls @code{indent-relative} with @code{t} as the @var{unindented-ok}
|
|
|
1935 argument. The return value is unpredictable.
|
|
|
1936
|
|
|
1937 If the previous nonblank line has no indent points beyond the current
|
|
|
1938 column, this command does nothing.
|
|
|
1939 @end deffn
|
|
|
1940
|
|
|
1941 @node Indent Tabs
|
|
|
1942 @subsection Adjustable ``Tab Stops''
|
|
|
1943 @cindex tabs stops for indentation
|
|
|
1944
|
|
|
1945 This section explains the mechanism for user-specified ``tab stops''
|
|
|
1946 and the mechanisms that use and set them. The name ``tab stops'' is
|
|
|
1947 used because the feature is similar to that of the tab stops on a
|
|
|
1948 typewriter. The feature works by inserting an appropriate number of
|
|
|
1949 spaces and tab characters to reach the next tab stop column; it does not
|
|
|
1950 affect the display of tab characters in the buffer (@pxref{Usual
|
|
|
1951 Display}). Note that the @key{TAB} character as input uses this tab
|
|
|
1952 stop feature only in a few major modes, such as Text mode.
|
|
|
1953
|
|
|
1954 @deffn Command tab-to-tab-stop
|
|
|
1955 This command inserts spaces or tabs up to the next tab stop column
|
|
|
1956 defined by @code{tab-stop-list}. It searches the list for an element
|
|
|
1957 greater than the current column number, and uses that element as the
|
|
|
1958 column to indent to. It does nothing if no such element is found.
|
|
|
1959 @end deffn
|
|
|
1960
|
|
|
1961 @defopt tab-stop-list
|
|
|
1962 This variable is the list of tab stop columns used by
|
|
|
1963 @code{tab-to-tab-stops}. The elements should be integers in increasing
|
|
|
1964 order. The tab stop columns need not be evenly spaced.
|
|
|
1965
|
|
|
1966 Use @kbd{M-x edit-tab-stops} to edit the location of tab stops
|
|
|
1967 interactively.
|
|
|
1968 @end defopt
|
|
|
1969
|
|
|
1970 @node Motion by Indent
|
|
|
1971 @subsection Indentation-Based Motion Commands
|
|
|
1972
|
|
|
1973 These commands, primarily for interactive use, act based on the
|
|
|
1974 indentation in the text.
|
|
|
1975
|
|
444
|
1976 @deffn Command back-to-indentation
|
|
428
|
1977 @comment !!SourceFile simple.el
|
|
|
1978 This command moves point to the first non-whitespace character in the
|
|
|
1979 current line (which is the line in which point is located). It returns
|
|
|
1980 @code{nil}.
|
|
|
1981 @end deffn
|
|
|
1982
|
|
|
1983 @deffn Command backward-to-indentation arg
|
|
|
1984 @comment !!SourceFile simple.el
|
|
|
1985 This command moves point backward @var{arg} lines and then to the
|
|
|
1986 first nonblank character on that line. It returns @code{nil}.
|
|
|
1987 @end deffn
|
|
|
1988
|
|
|
1989 @deffn Command forward-to-indentation arg
|
|
|
1990 @comment !!SourceFile simple.el
|
|
|
1991 This command moves point forward @var{arg} lines and then to the first
|
|
|
1992 nonblank character on that line. It returns @code{nil}.
|
|
|
1993 @end deffn
|
|
|
1994
|
|
|
1995 @node Case Changes
|
|
|
1996 @section Case Changes
|
|
|
1997 @cindex case changes
|
|
|
1998
|
|
|
1999 The case change commands described here work on text in the current
|
|
|
2000 buffer. @xref{Character Case}, for case conversion commands that work
|
|
|
2001 on strings and characters. @xref{Case Tables}, for how to customize
|
|
|
2002 which characters are upper or lower case and how to convert them.
|
|
|
2003
|
|
444
|
2004 @deffn Command capitalize-region start end &optional buffer
|
|
428
|
2005 This function capitalizes all words in the region defined by
|
|
|
2006 @var{start} and @var{end}. To capitalize means to convert each word's
|
|
|
2007 first character to upper case and convert the rest of each word to lower
|
|
|
2008 case. The function returns @code{nil}.
|
|
|
2009
|
|
|
2010 If one end of the region is in the middle of a word, the part of the
|
|
|
2011 word within the region is treated as an entire word.
|
|
|
2012
|
|
|
2013 When @code{capitalize-region} is called interactively, @var{start} and
|
|
|
2014 @var{end} are point and the mark, with the smallest first.
|
|
|
2015
|
|
|
2016 @example
|
|
|
2017 @group
|
|
|
2018 ---------- Buffer: foo ----------
|
|
|
2019 This is the contents of the 5th foo.
|
|
|
2020 ---------- Buffer: foo ----------
|
|
|
2021 @end group
|
|
|
2022
|
|
|
2023 @group
|
|
|
2024 (capitalize-region 1 44)
|
|
|
2025 @result{} nil
|
|
|
2026
|
|
|
2027 ---------- Buffer: foo ----------
|
|
|
2028 This Is The Contents Of The 5th Foo.
|
|
|
2029 ---------- Buffer: foo ----------
|
|
|
2030 @end group
|
|
|
2031 @end example
|
|
|
2032 @end deffn
|
|
|
2033
|
|
444
|
2034 @deffn Command downcase-region start end &optional buffer
|
|
428
|
2035 This function converts all of the letters in the region defined by
|
|
|
2036 @var{start} and @var{end} to lower case. The function returns
|
|
|
2037 @code{nil}.
|
|
|
2038
|
|
|
2039 When @code{downcase-region} is called interactively, @var{start} and
|
|
|
2040 @var{end} are point and the mark, with the smallest first.
|
|
|
2041 @end deffn
|
|
|
2042
|
|
444
|
2043 @deffn Command upcase-region start end &optional buffer
|
|
428
|
2044 This function converts all of the letters in the region defined by
|
|
|
2045 @var{start} and @var{end} to upper case. The function returns
|
|
|
2046 @code{nil}.
|
|
|
2047
|
|
|
2048 When @code{upcase-region} is called interactively, @var{start} and
|
|
|
2049 @var{end} are point and the mark, with the smallest first.
|
|
|
2050 @end deffn
|
|
|
2051
|
|
444
|
2052 @deffn Command capitalize-word count &optional buffer
|
|
428
|
2053 This function capitalizes @var{count} words after point, moving point
|
|
|
2054 over as it does. To capitalize means to convert each word's first
|
|
|
2055 character to upper case and convert the rest of each word to lower case.
|
|
|
2056 If @var{count} is negative, the function capitalizes the
|
|
|
2057 @minus{}@var{count} previous words but does not move point. The value
|
|
|
2058 is @code{nil}.
|
|
|
2059
|
|
|
2060 If point is in the middle of a word, the part of the word before point
|
|
|
2061 is ignored when moving forward. The rest is treated as an entire word.
|
|
|
2062
|
|
|
2063 When @code{capitalize-word} is called interactively, @var{count} is
|
|
|
2064 set to the numeric prefix argument.
|
|
|
2065 @end deffn
|
|
|
2066
|
|
444
|
2067 @deffn Command downcase-word count &optional buffer
|
|
428
|
2068 This function converts the @var{count} words after point to all lower
|
|
|
2069 case, moving point over as it does. If @var{count} is negative, it
|
|
|
2070 converts the @minus{}@var{count} previous words but does not move point.
|
|
|
2071 The value is @code{nil}.
|
|
|
2072
|
|
|
2073 When @code{downcase-word} is called interactively, @var{count} is set
|
|
|
2074 to the numeric prefix argument.
|
|
|
2075 @end deffn
|
|
|
2076
|
|
444
|
2077 @deffn Command upcase-word count &optional buffer
|
|
428
|
2078 This function converts the @var{count} words after point to all upper
|
|
|
2079 case, moving point over as it does. If @var{count} is negative, it
|
|
|
2080 converts the @minus{}@var{count} previous words but does not move point.
|
|
|
2081 The value is @code{nil}.
|
|
|
2082
|
|
|
2083 When @code{upcase-word} is called interactively, @var{count} is set to
|
|
|
2084 the numeric prefix argument.
|
|
|
2085 @end deffn
|
|
|
2086
|
|
|
2087 @node Text Properties
|
|
|
2088 @section Text Properties
|
|
|
2089 @cindex text properties
|
|
|
2090 @cindex attributes of text
|
|
|
2091 @cindex properties of text
|
|
|
2092
|
|
|
2093 Text properties are an alternative interface to extents
|
|
|
2094 (@pxref{Extents}), and are built on top of them. They are useful when
|
|
|
2095 you want to view textual properties as being attached to the characters
|
|
|
2096 themselves rather than to intervals of characters. The text property
|
|
|
2097 interface is compatible with FSF Emacs.
|
|
|
2098
|
|
|
2099 Each character position in a buffer or a string can have a @dfn{text
|
|
|
2100 property list}, much like the property list of a symbol (@pxref{Property
|
|
|
2101 Lists}). The properties belong to a particular character at a
|
|
|
2102 particular place, such as, the letter @samp{T} at the beginning of this
|
|
|
2103 sentence or the first @samp{o} in @samp{foo}---if the same character
|
|
|
2104 occurs in two different places, the two occurrences generally have
|
|
|
2105 different properties.
|
|
|
2106
|
|
|
2107 Each property has a name and a value. Both of these can be any Lisp
|
|
|
2108 object, but the name is normally a symbol. The usual way to access the
|
|
|
2109 property list is to specify a name and ask what value corresponds to it.
|
|
|
2110
|
|
|
2111 @ignore
|
|
|
2112 If a character has a @code{category} property, we call it the
|
|
|
2113 @dfn{category} of the character. It should be a symbol. The properties
|
|
|
2114 of the symbol serve as defaults for the properties of the character.
|
|
|
2115 @end ignore
|
|
|
2116 Note that FSF Emacs also looks at the @code{category} property to find
|
|
|
2117 defaults for text properties. We consider this too bogus to implement.
|
|
|
2118
|
|
|
2119 Copying text between strings and buffers preserves the properties
|
|
|
2120 along with the characters; this includes such diverse functions as
|
|
|
2121 @code{substring}, @code{insert}, and @code{buffer-substring}.
|
|
|
2122
|
|
|
2123 @menu
|
|
|
2124 * Examining Properties:: Looking at the properties of one character.
|
|
|
2125 * Changing Properties:: Setting the properties of a range of text.
|
|
|
2126 * Property Search:: Searching for where a property changes value.
|
|
|
2127 * Special Properties:: Particular properties with special meanings.
|
|
|
2128 * Saving Properties:: Saving text properties in files, and reading
|
|
|
2129 them back.
|
|
2256
|
2130 * Fields:: Emacs-compatible text fields.
|
|
428
|
2131 @end menu
|
|
|
2132
|
|
|
2133 @node Examining Properties
|
|
|
2134 @subsection Examining Text Properties
|
|
|
2135
|
|
|
2136 The simplest way to examine text properties is to ask for the value of
|
|
|
2137 a particular property of a particular character. For that, use
|
|
|
2138 @code{get-text-property}. Use @code{text-properties-at} to get the
|
|
|
2139 entire property list of a character. @xref{Property Search}, for
|
|
|
2140 functions to examine the properties of a number of characters at once.
|
|
|
2141
|
|
|
2142 These functions handle both strings and buffers. (Keep in mind that
|
|
|
2143 positions in a string start from 0, whereas positions in a buffer start
|
|
|
2144 from 1.)
|
|
|
2145
|
|
444
|
2146 @defun get-text-property pos prop &optional object at-flag
|
|
428
|
2147 This function returns the value of the @var{prop} property of the
|
|
|
2148 character after position @var{pos} in @var{object} (a buffer or string).
|
|
|
2149 The argument @var{object} is optional and defaults to the current
|
|
|
2150 buffer.
|
|
|
2151 @ignore @c Bogus as hell!
|
|
|
2152 If there is no @var{prop} property strictly speaking, but the character
|
|
|
2153 has a category that is a symbol, then @code{get-text-property} returns
|
|
|
2154 the @var{prop} property of that symbol.
|
|
|
2155 @end ignore
|
|
|
2156 @end defun
|
|
|
2157
|
|
444
|
2158 @defun get-char-property pos prop &optional object at-flag
|
|
428
|
2159 This function is like @code{get-text-property}, except that it checks
|
|
|
2160 all extents, not just text-property extents.
|
|
|
2161
|
|
|
2162 @ignore Does not apply in XEmacs
|
|
|
2163 The argument @var{object} may be a string, a buffer, or a window. If it
|
|
|
2164 is a window, then the buffer displayed in that window is used for text
|
|
|
2165 properties and overlays, but only the overlays active for that window
|
|
|
2166 are considered. If @var{object} is a buffer, then all overlays in that
|
|
|
2167 buffer are considered, as well as text properties. If @var{object} is a
|
|
|
2168 string, only text properties are considered, since strings never have
|
|
|
2169 overlays.
|
|
|
2170 @end ignore
|
|
|
2171 @end defun
|
|
|
2172
|
|
|
2173 @defun text-properties-at position &optional object
|
|
|
2174 This function returns the entire property list of the character at
|
|
|
2175 @var{position} in the string or buffer @var{object}. If @var{object} is
|
|
|
2176 @code{nil}, it defaults to the current buffer.
|
|
|
2177 @end defun
|
|
|
2178
|
|
|
2179 @defvar default-text-properties
|
|
|
2180 This variable holds a property list giving default values for text
|
|
|
2181 properties. Whenever a character does not specify a value for a
|
|
|
2182 property, the value stored in this list is used instead. Here is
|
|
|
2183 an example:
|
|
|
2184
|
|
|
2185 @example
|
|
|
2186 (setq default-text-properties '(foo 69))
|
|
|
2187 ;; @r{Make sure character 1 has no properties of its own.}
|
|
|
2188 (set-text-properties 1 2 nil)
|
|
|
2189 ;; @r{What we get, when we ask, is the default value.}
|
|
|
2190 (get-text-property 1 'foo)
|
|
|
2191 @result{} 69
|
|
|
2192 @end example
|
|
|
2193 @end defvar
|
|
|
2194
|
|
|
2195 @node Changing Properties
|
|
|
2196 @subsection Changing Text Properties
|
|
|
2197
|
|
|
2198 The primitives for changing properties apply to a specified range of
|
|
|
2199 text. The function @code{set-text-properties} (see end of section) sets
|
|
|
2200 the entire property list of the text in that range; more often, it is
|
|
|
2201 useful to add, change, or delete just certain properties specified by
|
|
|
2202 name.
|
|
|
2203
|
|
|
2204 Since text properties are considered part of the buffer's contents, and
|
|
|
2205 can affect how the buffer looks on the screen, any change in the text
|
|
|
2206 properties is considered a buffer modification. Buffer text property
|
|
|
2207 changes are undoable (@pxref{Undo}).
|
|
|
2208
|
|
|
2209 @defun put-text-property start end prop value &optional object
|
|
|
2210 This function sets the @var{prop} property to @var{value} for the text
|
|
|
2211 between @var{start} and @var{end} in the string or buffer @var{object}.
|
|
|
2212 If @var{object} is @code{nil}, it defaults to the current buffer.
|
|
|
2213 @end defun
|
|
|
2214
|
|
|
2215 @defun add-text-properties start end props &optional object
|
|
|
2216 This function modifies the text properties for the text between
|
|
|
2217 @var{start} and @var{end} in the string or buffer @var{object}. If
|
|
|
2218 @var{object} is @code{nil}, it defaults to the current buffer.
|
|
|
2219
|
|
|
2220 The argument @var{props} specifies which properties to change. It
|
|
|
2221 should have the form of a property list (@pxref{Property Lists}): a list
|
|
|
2222 whose elements include the property names followed alternately by the
|
|
|
2223 corresponding values.
|
|
|
2224
|
|
|
2225 The return value is @code{t} if the function actually changed some
|
|
|
2226 property's value; @code{nil} otherwise (if @var{props} is @code{nil} or
|
|
|
2227 its values agree with those in the text).
|
|
|
2228
|
|
|
2229 For example, here is how to set the @code{comment} and @code{face}
|
|
|
2230 properties of a range of text:
|
|
|
2231
|
|
|
2232 @example
|
|
|
2233 (add-text-properties @var{start} @var{end}
|
|
|
2234 '(comment t face highlight))
|
|
|
2235 @end example
|
|
|
2236 @end defun
|
|
|
2237
|
|
|
2238 @defun remove-text-properties start end props &optional object
|
|
|
2239 This function deletes specified text properties from the text between
|
|
|
2240 @var{start} and @var{end} in the string or buffer @var{object}. If
|
|
|
2241 @var{object} is @code{nil}, it defaults to the current buffer.
|
|
|
2242
|
|
|
2243 The argument @var{props} specifies which properties to delete. It
|
|
|
2244 should have the form of a property list (@pxref{Property Lists}): a list
|
|
|
2245 whose elements are property names alternating with corresponding values.
|
|
|
2246 But only the names matter---the values that accompany them are ignored.
|
|
|
2247 For example, here's how to remove the @code{face} property.
|
|
|
2248
|
|
|
2249 @example
|
|
|
2250 (remove-text-properties @var{start} @var{end} '(face nil))
|
|
|
2251 @end example
|
|
|
2252
|
|
|
2253 The return value is @code{t} if the function actually changed some
|
|
|
2254 property's value; @code{nil} otherwise (if @var{props} is @code{nil} or
|
|
|
2255 if no character in the specified text had any of those properties).
|
|
|
2256 @end defun
|
|
|
2257
|
|
|
2258 @defun set-text-properties start end props &optional object
|
|
|
2259 This function completely replaces the text property list for the text
|
|
|
2260 between @var{start} and @var{end} in the string or buffer @var{object}.
|
|
|
2261 If @var{object} is @code{nil}, it defaults to the current buffer.
|
|
|
2262
|
|
|
2263 The argument @var{props} is the new property list. It should be a list
|
|
|
2264 whose elements are property names alternating with corresponding values.
|
|
|
2265
|
|
|
2266 After @code{set-text-properties} returns, all the characters in the
|
|
|
2267 specified range have identical properties.
|
|
|
2268
|
|
|
2269 If @var{props} is @code{nil}, the effect is to get rid of all properties
|
|
|
2270 from the specified range of text. Here's an example:
|
|
|
2271
|
|
|
2272 @example
|
|
|
2273 (set-text-properties @var{start} @var{end} nil)
|
|
|
2274 @end example
|
|
|
2275 @end defun
|
|
|
2276
|
|
|
2277 See also the function @code{buffer-substring-without-properties}
|
|
|
2278 (@pxref{Buffer Contents}) which copies text from the buffer
|
|
|
2279 but does not copy its properties.
|
|
|
2280
|
|
|
2281 @node Property Search
|
|
|
2282 @subsection Property Search Functions
|
|
|
2283
|
|
|
2284 In typical use of text properties, most of the time several or many
|
|
|
2285 consecutive characters have the same value for a property. Rather than
|
|
|
2286 writing your programs to examine characters one by one, it is much
|
|
|
2287 faster to process chunks of text that have the same property value.
|
|
|
2288
|
|
|
2289 Here are functions you can use to do this. They use @code{eq} for
|
|
|
2290 comparing property values. In all cases, @var{object} defaults to the
|
|
|
2291 current buffer.
|
|
|
2292
|
|
|
2293 For high performance, it's very important to use the @var{limit}
|
|
|
2294 argument to these functions, especially the ones that search for a
|
|
|
2295 single property---otherwise, they may spend a long time scanning to the
|
|
|
2296 end of the buffer, if the property you are interested in does not change.
|
|
|
2297
|
|
|
2298 Remember that a position is always between two characters; the position
|
|
|
2299 returned by these functions is between two characters with different
|
|
|
2300 properties.
|
|
|
2301
|
|
|
2302 @defun next-property-change pos &optional object limit
|
|
|
2303 The function scans the text forward from position @var{pos} in the
|
|
|
2304 string or buffer @var{object} till it finds a change in some text
|
|
|
2305 property, then returns the position of the change. In other words, it
|
|
|
2306 returns the position of the first character beyond @var{pos} whose
|
|
|
2307 properties are not identical to those of the character just after
|
|
|
2308 @var{pos}.
|
|
|
2309
|
|
|
2310 If @var{limit} is non-@code{nil}, then the scan ends at position
|
|
444
|
2311 @var{limit}. If there is no property change before that point,
|
|
428
|
2312 @code{next-property-change} returns @var{limit}.
|
|
|
2313
|
|
|
2314 The value is @code{nil} if the properties remain unchanged all the way
|
|
|
2315 to the end of @var{object} and @var{limit} is @code{nil}. If the value
|
|
|
2316 is non-@code{nil}, it is a position greater than or equal to @var{pos}.
|
|
|
2317 The value equals @var{pos} only when @var{limit} equals @var{pos}.
|
|
|
2318
|
|
|
2319 Here is an example of how to scan the buffer by chunks of text within
|
|
|
2320 which all properties are constant:
|
|
|
2321
|
|
|
2322 @smallexample
|
|
|
2323 (while (not (eobp))
|
|
|
2324 (let ((plist (text-properties-at (point)))
|
|
|
2325 (next-change
|
|
|
2326 (or (next-property-change (point) (current-buffer))
|
|
|
2327 (point-max))))
|
|
|
2328 @r{Process text from point to @var{next-change}@dots{}}
|
|
|
2329 (goto-char next-change)))
|
|
|
2330 @end smallexample
|
|
|
2331 @end defun
|
|
|
2332
|
|
|
2333 @defun next-single-property-change pos prop &optional object limit
|
|
|
2334 The function scans the text forward from position @var{pos} in the
|
|
|
2335 string or buffer @var{object} till it finds a change in the @var{prop}
|
|
|
2336 property, then returns the position of the change. In other words, it
|
|
|
2337 returns the position of the first character beyond @var{pos} whose
|
|
|
2338 @var{prop} property differs from that of the character just after
|
|
|
2339 @var{pos}.
|
|
|
2340
|
|
|
2341 If @var{limit} is non-@code{nil}, then the scan ends at position
|
|
444
|
2342 @var{limit}. If there is no property change before that point,
|
|
428
|
2343 @code{next-single-property-change} returns @var{limit}.
|
|
|
2344
|
|
|
2345 The value is @code{nil} if the property remains unchanged all the way to
|
|
|
2346 the end of @var{object} and @var{limit} is @code{nil}. If the value is
|
|
|
2347 non-@code{nil}, it is a position greater than or equal to @var{pos}; it
|
|
|
2348 equals @var{pos} only if @var{limit} equals @var{pos}.
|
|
|
2349 @end defun
|
|
|
2350
|
|
|
2351 @defun previous-property-change pos &optional object limit
|
|
444
|
2352 This is like @code{next-property-change}, but scans backward from @var{pos}
|
|
428
|
2353 instead of forward. If the value is non-@code{nil}, it is a position
|
|
|
2354 less than or equal to @var{pos}; it equals @var{pos} only if @var{limit}
|
|
|
2355 equals @var{pos}.
|
|
|
2356 @end defun
|
|
|
2357
|
|
|
2358 @defun previous-single-property-change pos prop &optional object limit
|
|
444
|
2359 This is like @code{next-single-property-change}, but scans backward from
|
|
428
|
2360 @var{pos} instead of forward. If the value is non-@code{nil}, it is a
|
|
|
2361 position less than or equal to @var{pos}; it equals @var{pos} only if
|
|
|
2362 @var{limit} equals @var{pos}.
|
|
|
2363 @end defun
|
|
|
2364
|
|
|
2365 @defun text-property-any start end prop value &optional object
|
|
|
2366 This function returns non-@code{nil} if at least one character between
|
|
|
2367 @var{start} and @var{end} has a property @var{prop} whose value is
|
|
|
2368 @var{value}. More precisely, it returns the position of the first such
|
|
|
2369 character. Otherwise, it returns @code{nil}.
|
|
|
2370
|
|
|
2371 The optional fifth argument, @var{object}, specifies the string or
|
|
|
2372 buffer to scan. Positions are relative to @var{object}. The default
|
|
|
2373 for @var{object} is the current buffer.
|
|
|
2374 @end defun
|
|
|
2375
|
|
|
2376 @defun text-property-not-all start end prop value &optional object
|
|
|
2377 This function returns non-@code{nil} if at least one character between
|
|
|
2378 @var{start} and @var{end} has a property @var{prop} whose value differs
|
|
|
2379 from @var{value}. More precisely, it returns the position of the
|
|
|
2380 first such character. Otherwise, it returns @code{nil}.
|
|
|
2381
|
|
|
2382 The optional fifth argument, @var{object}, specifies the string or
|
|
|
2383 buffer to scan. Positions are relative to @var{object}. The default
|
|
|
2384 for @var{object} is the current buffer.
|
|
|
2385 @end defun
|
|
|
2386
|
|
|
2387 @node Special Properties
|
|
|
2388 @subsection Properties with Special Meanings
|
|
|
2389
|
|
|
2390 The predefined properties are the same as those for extents.
|
|
|
2391 @xref{Extent Properties}.
|
|
|
2392
|
|
|
2393 @ignore Changed in XEmacs
|
|
|
2394 (deleted section describing FSF Emacs special text properties)
|
|
|
2395 @end ignore
|
|
|
2396
|
|
|
2397 @node Saving Properties
|
|
|
2398 @subsection Saving Text Properties in Files
|
|
|
2399 @cindex text properties in files
|
|
|
2400 @cindex saving text properties
|
|
|
2401
|
|
|
2402 You can save text properties in files, and restore text properties
|
|
444
|
2403 when inserting the files, using these two hooks:
|
|
428
|
2404
|
|
|
2405 @defvar write-region-annotate-functions
|
|
|
2406 This variable's value is a list of functions for @code{write-region} to
|
|
|
2407 run to encode text properties in some fashion as annotations to the text
|
|
|
2408 being written in the file. @xref{Writing to Files}.
|
|
|
2409
|
|
|
2410 Each function in the list is called with two arguments: the start and
|
|
|
2411 end of the region to be written. These functions should not alter the
|
|
|
2412 contents of the buffer. Instead, they should return lists indicating
|
|
|
2413 annotations to write in the file in addition to the text in the
|
|
|
2414 buffer.
|
|
|
2415
|
|
|
2416 Each function should return a list of elements of the form
|
|
|
2417 @code{(@var{position} . @var{string})}, where @var{position} is an
|
|
|
2418 integer specifying the relative position in the text to be written, and
|
|
|
2419 @var{string} is the annotation to add there.
|
|
|
2420
|
|
|
2421 Each list returned by one of these functions must be already sorted in
|
|
|
2422 increasing order by @var{position}. If there is more than one function,
|
|
|
2423 @code{write-region} merges the lists destructively into one sorted list.
|
|
|
2424
|
|
|
2425 When @code{write-region} actually writes the text from the buffer to the
|
|
|
2426 file, it intermixes the specified annotations at the corresponding
|
|
|
2427 positions. All this takes place without modifying the buffer.
|
|
|
2428 @end defvar
|
|
|
2429
|
|
|
2430 @defvar after-insert-file-functions
|
|
|
2431 This variable holds a list of functions for @code{insert-file-contents}
|
|
|
2432 to call after inserting a file's contents. These functions should scan
|
|
|
2433 the inserted text for annotations, and convert them to the text
|
|
|
2434 properties they stand for.
|
|
|
2435
|
|
|
2436 Each function receives one argument, the length of the inserted text;
|
|
|
2437 point indicates the start of that text. The function should scan that
|
|
|
2438 text for annotations, delete them, and create the text properties that
|
|
|
2439 the annotations specify. The function should return the updated length
|
|
|
2440 of the inserted text, as it stands after those changes. The value
|
|
|
2441 returned by one function becomes the argument to the next function.
|
|
|
2442
|
|
|
2443 These functions should always return with point at the beginning of
|
|
|
2444 the inserted text.
|
|
|
2445
|
|
|
2446 The intended use of @code{after-insert-file-functions} is for converting
|
|
|
2447 some sort of textual annotations into actual text properties. But other
|
|
|
2448 uses may be possible.
|
|
|
2449 @end defvar
|
|
|
2450
|
|
|
2451 We invite users to write Lisp programs to store and retrieve text
|
|
|
2452 properties in files, using these hooks, and thus to experiment with
|
|
444
|
2453 various data formats and find good ones. Eventually we hope users
|
|
428
|
2454 will produce good, general extensions we can install in Emacs.
|
|
|
2455
|
|
|
2456 We suggest not trying to handle arbitrary Lisp objects as property
|
|
|
2457 names or property values---because a program that general is probably
|
|
|
2458 difficult to write, and slow. Instead, choose a set of possible data
|
|
|
2459 types that are reasonably flexible, and not too hard to encode.
|
|
|
2460
|
|
|
2461 @xref{Format Conversion}, for a related feature.
|
|
|
2462
|
|
2256
|
2463 @node Fields
|
|
|
2464 @subsection Fields
|
|
|
2465 @cindex text fields
|
|
|
2466 @cindex fields
|
|
|
2467
|
|
|
2468 Emacs supplies a notion of a @emph{text field}, which is a region of
|
|
|
2469 text where every character has the same value of the @code{field}
|
|
|
2470 property. It is used to identify regions of a buffer used for
|
|
|
2471 communicating with an external process, for example. XEmacs supplies a
|
|
|
2472 compatible interface. In XEmacs, the @code{field} property can be set
|
|
|
2473 as either an extent property or a text property, mirroring the Emacs
|
|
|
2474 capability of using either overlays or text properties.
|
|
|
2475
|
|
|
2476 The field manipulating functions take a buffer position as the
|
|
|
2477 field-identifying argument, defaulting to point. This really means the
|
|
|
2478 field containing that buffer position. Consecutive buffer positions
|
|
|
2479 with no @code{field} property are considered an ``empty'' field. There
|
|
|
2480 is some ambiguity when a specified buffer position falls at the very
|
|
|
2481 beginning or the very end of a field: does it belong to the preceding or
|
|
|
2482 the following field? The answer depends on the openness or closedness
|
|
|
2483 of the corresponding extents (@pxref{Extent Endpoints}). A buffer
|
|
|
2484 position corresponds to the field whose property would be inherited by a
|
|
|
2485 character inserted at that position. If the buffer position is between
|
|
|
2486 an end-open and a start-open extent, then it corresponds to an empty
|
|
|
2487 field at that position, since an inserted character will belong to
|
|
|
2488 neither extent.
|
|
|
2489
|
|
|
2490 @defvar inhibit-field-text-motion
|
|
|
2491 This variable controls whether the text motion commands notice fields or
|
|
|
2492 not. When it is nil (the default), commands such as beginning-of-line
|
|
|
2493 will try to move only within fields.
|
|
|
2494 @end defvar
|
|
|
2495
|
|
|
2496 @defun make-field value from to &optional buffer
|
|
|
2497 There is no Emacs counterpart to this function. The default open and
|
|
|
2498 closedness of extents in XEmacs is opposite to the default for Emacs
|
|
|
2499 overlays. Hence, fields based on extents in XEmacs behave differently
|
|
|
2500 from the equivalent fields based on overlays in Emacs. This function
|
|
|
2501 creates a field with value @var{value} over the region @var{from} to
|
|
|
2502 @var{to} in @var{buffer}, which defaults to the current buffer, with the
|
|
|
2503 default Emacs open and closedness.
|
|
|
2504 @end defun
|
|
|
2505
|
|
|
2506 @defun find-field &optional pos merge-at-boundary beg-limit end-limit
|
|
|
2507 There is no (Lisp-visible) Emacs counterpart to this function. It is
|
|
|
2508 the workhorse for the other functions. It returns a dotted pair
|
|
|
2509 @code{(start . stop)} holding the endpoints of the field matching a
|
|
|
2510 specification. If @var{pos} is non-@code{nil}, it specifies a buffer
|
|
|
2511 position whose enclosing field should be found; otherwise, the value of
|
|
|
2512 point is used.
|
|
|
2513
|
|
|
2514 If @var{merge-at-boundary} is non-@code{nil}, then two changes are made
|
|
|
2515 to the search algorithm. First, if @var{pos} is at the very first
|
|
|
2516 position of a field, then the beginning of the previous field is
|
|
|
2517 returned instead of the beginning of @var{pos}'s field. Second, if the
|
|
|
2518 value of the @code{field} property at @var{pos} is the symbol
|
|
|
2519 @code{boundary}, then the beginning of the field before the boundary
|
|
|
2520 field and the end of the field after the boundary field are returned.
|
|
|
2521
|
|
|
2522 If @var{beg-limit} is a buffer position, and the start position that
|
|
|
2523 would be returned is less than @var{beg-limit}, then @var{beg-limit} is
|
|
|
2524 returned instead. Likewise, if @var{end-limit} is a buffer position,
|
|
|
2525 and the stop position that would be returned is greater than
|
|
|
2526 @var{end-limit}, then @var{end-limit} is returned instead.
|
|
|
2527 @end defun
|
|
|
2528
|
|
|
2529 @defun delete-field &optional pos
|
|
|
2530 Delete the text of the field at @var{pos}.
|
|
|
2531 @end defun
|
|
|
2532
|
|
|
2533 @defun field-string &optional pos
|
|
|
2534 Return the contents of the field at @var{pos} as a string.
|
|
|
2535 @end defun
|
|
|
2536
|
|
|
2537 @defun field-string-no-properties &optional pos
|
|
|
2538 Return the contents of the field at @var{pos} as a string, without text
|
|
|
2539 properties.
|
|
|
2540 @end defun
|
|
|
2541
|
|
|
2542 @defun field-beginning &optional pos escape-from-edge limit
|
|
|
2543 Return the beginning of the field at @var{pos}. If
|
|
|
2544 @var{escape-from-edge} is non-nil and @var{pos} is at the beginning of a
|
|
|
2545 field, then the beginning of the field that ends at @var{pos} is
|
|
|
2546 returned instead. If @var{limit} is a buffer position and the returned
|
|
|
2547 value would be less than @var{limit}, then @var{limit} is returned
|
|
|
2548 instead.
|
|
|
2549 @end defun
|
|
|
2550
|
|
|
2551 @defun field-end &optional pos escape-from-edge limit
|
|
|
2552 Return the end of the field at @var{pos}. If @var{escape-from-edge} is
|
|
|
2553 non-nil and @var{pos} is at the end of a field, then the end of the
|
|
|
2554 field that begins at @var{pos} is returned instead. If @var{limit} is a
|
|
|
2555 buffer position and the returned value would be greater than
|
|
|
2556 @var{limit}, then @var{limit} is returned instead.
|
|
|
2557 @end defun
|
|
|
2558
|
|
|
2559 @defun constrain-to-field new-pos old-pos &optional escape-from-edge only-in-line inhibit-capture-property
|
|
|
2560 Return the position closest to @var{new-pos} that is in the same field
|
|
|
2561 as @var{old-pos}. If @var{new-pos} is @code{nil}, then the value of
|
|
|
2562 point is used instead @emph{and} point is set to the value that is
|
|
|
2563 returned.
|
|
|
2564
|
|
|
2565 If @var{escape-from-edge} is non-@code{nil} and @var{old-pos} is at the
|
|
|
2566 boundary of two fields, then the two adjacent fields are considered one
|
|
|
2567 field. Furthermore, if @var{new-pos} is in a field whose @code{field}
|
|
|
2568 property is the symbol @code{boundary}, then the preceding field, the
|
|
|
2569 boundary field, and the following field are considered one field.
|
|
|
2570
|
|
|
2571 If @var{only-in-line} is non-@code{nil} and the returned position would
|
|
|
2572 be on a different line than @var{new-pos}, return @var{new-pos} instead.
|
|
|
2573
|
|
|
2574 If @var{inhibit-capture-property} is non-@code{nil} and the character at
|
|
|
2575 @var{old-pos} has a property of the same name as the value of
|
|
|
2576 @var{inhibit-capture-property}, then all field boundaries are ignored;
|
|
|
2577 i.e., @var{new-pos} is returned.
|
|
|
2578
|
|
|
2579 If @var{inhibit-field-text-motion} is non-@code{nil}, then all field
|
|
|
2580 boundaries are ignored and this function always returns @var{new-pos}.
|
|
|
2581 @end defun
|
|
|
2582
|
|
428
|
2583 @node Substitution
|
|
|
2584 @section Substituting for a Character Code
|
|
|
2585
|
|
|
2586 The following functions replace characters within a specified region
|
|
|
2587 based on their character codes.
|
|
|
2588
|
|
|
2589 @defun subst-char-in-region start end old-char new-char &optional noundo
|
|
|
2590 @cindex replace characters
|
|
|
2591 This function replaces all occurrences of the character @var{old-char}
|
|
|
2592 with the character @var{new-char} in the region of the current buffer
|
|
|
2593 defined by @var{start} and @var{end}.
|
|
|
2594
|
|
|
2595 @cindex Outline mode
|
|
|
2596 @cindex undo avoidance
|
|
|
2597 If @var{noundo} is non-@code{nil}, then @code{subst-char-in-region} does
|
|
|
2598 not record the change for undo and does not mark the buffer as modified.
|
|
|
2599 This feature is used for controlling selective display (@pxref{Selective
|
|
|
2600 Display}).
|
|
|
2601
|
|
|
2602 @code{subst-char-in-region} does not move point and returns
|
|
|
2603 @code{nil}.
|
|
|
2604
|
|
|
2605 @example
|
|
|
2606 @group
|
|
|
2607 ---------- Buffer: foo ----------
|
|
|
2608 This is the contents of the buffer before.
|
|
|
2609 ---------- Buffer: foo ----------
|
|
|
2610 @end group
|
|
|
2611
|
|
|
2612 @group
|
|
|
2613 (subst-char-in-region 1 20 ?i ?X)
|
|
|
2614 @result{} nil
|
|
|
2615
|
|
|
2616 ---------- Buffer: foo ----------
|
|
|
2617 ThXs Xs the contents of the buffer before.
|
|
|
2618 ---------- Buffer: foo ----------
|
|
|
2619 @end group
|
|
|
2620 @end example
|
|
|
2621 @end defun
|
|
|
2622
|
|
|
2623 @defun translate-region start end table
|
|
|
2624 This function applies a translation table to the characters in the
|
|
|
2625 buffer between positions @var{start} and @var{end}. The translation
|
|
|
2626 table @var{table} can be either a string, a vector, or a char-table.
|
|
|
2627
|
|
444
|
2628 If @var{table} is a string, its @var{n}th element is the mapping for the
|
|
428
|
2629 character with code @var{n}.
|
|
|
2630
|
|
|
2631 If @var{table} is a vector, its @var{n}th element is the mapping for
|
|
|
2632 character with code @var{n}. Legal mappings are characters, strings, or
|
|
|
2633 @code{nil} (meaning don't replace.)
|
|
|
2634
|
|
|
2635 If @var{table} is a char-table, its elements describe the mapping
|
|
|
2636 between characters and their replacements. The char-table should be of
|
|
|
2637 type @code{char} or @code{generic}.
|
|
|
2638
|
|
|
2639 When the @var{table} is a string or vector and its length is less than
|
|
|
2640 the total number of characters (256 without Mule), any characters with
|
|
|
2641 codes larger than the length of @var{table} are not altered by the
|
|
|
2642 translation.
|
|
|
2643
|
|
|
2644 The return value of @code{translate-region} is the number of
|
|
|
2645 characters that were actually changed by the translation. This does
|
|
|
2646 not count characters that were mapped into themselves in the
|
|
|
2647 translation table.
|
|
|
2648
|
|
|
2649 @strong{NOTE}: Prior to XEmacs 21.2, the @var{table} argument was
|
|
|
2650 allowed only to be a string. This is still the case in FSF Emacs.
|
|
|
2651
|
|
|
2652 The following example creates a char-table that is passed to
|
|
|
2653 @code{translate-region}, which translates character @samp{a} to
|
|
|
2654 @samp{the letter a}, removes character @samp{b}, and translates
|
|
|
2655 character @samp{c} to newline.
|
|
|
2656
|
|
|
2657 @example
|
|
|
2658 @group
|
|
|
2659 ---------- Buffer: foo ----------
|
|
|
2660 Here is a sentence in the buffer.
|
|
|
2661 ---------- Buffer: foo ----------
|
|
|
2662 @end group
|
|
|
2663
|
|
|
2664 @group
|
|
|
2665 (let ((table (make-char-table 'generic)))
|
|
|
2666 (put-char-table ?a "the letter a" table)
|
|
|
2667 (put-char-table ?b "" table)
|
|
|
2668 (put-char-table ?c ?\n table)
|
|
|
2669 (translate-region (point-min) (point-max) table))
|
|
|
2670 @result{} 3
|
|
|
2671
|
|
|
2672 ---------- Buffer: foo ----------
|
|
|
2673 Here is the letter a senten
|
|
|
2674 e in the uffer.
|
|
|
2675 ---------- Buffer: foo ----------
|
|
|
2676 @end group
|
|
|
2677 @end example
|
|
|
2678 @end defun
|
|
|
2679
|
|
|
2680 @node Registers
|
|
|
2681 @section Registers
|
|
|
2682 @cindex registers
|
|
|
2683
|
|
|
2684 A register is a sort of variable used in XEmacs editing that can hold a
|
|
|
2685 marker, a string, a rectangle, a window configuration (of one frame), or
|
|
|
2686 a frame configuration (of all frames). Each register is named by a
|
|
|
2687 single character. All characters, including control and meta characters
|
|
|
2688 (but with the exception of @kbd{C-g}), can be used to name registers.
|
|
|
2689 Thus, there are 255 possible registers. A register is designated in
|
|
|
2690 Emacs Lisp by a character that is its name.
|
|
|
2691
|
|
|
2692 The functions in this section return unpredictable values unless
|
|
|
2693 otherwise stated.
|
|
|
2694 @c Will change in version 19
|
|
|
2695
|
|
|
2696 @defvar register-alist
|
|
|
2697 This variable is an alist of elements of the form @code{(@var{name} .
|
|
|
2698 @var{contents})}. Normally, there is one element for each XEmacs
|
|
|
2699 register that has been used.
|
|
|
2700
|
|
|
2701 The object @var{name} is a character (an integer) identifying the
|
|
|
2702 register. The object @var{contents} is a string, marker, or list
|
|
|
2703 representing the register contents. A string represents text stored in
|
|
|
2704 the register. A marker represents a position. A list represents a
|
|
|
2705 rectangle; its elements are strings, one per line of the rectangle.
|
|
|
2706 @end defvar
|
|
|
2707
|
|
444
|
2708 @defun get-register register
|
|
428
|
2709 This function returns the contents of the register
|
|
444
|
2710 @var{register}, or @code{nil} if it has no contents.
|
|
428
|
2711 @end defun
|
|
|
2712
|
|
444
|
2713 @defun set-register register value
|
|
|
2714 This function sets the contents of register @var{register} to @var{value}.
|
|
428
|
2715 A register can be set to any value, but the other register functions
|
|
|
2716 expect only certain data types. The return value is @var{value}.
|
|
|
2717 @end defun
|
|
|
2718
|
|
444
|
2719 @deffn Command view-register register
|
|
|
2720 This command displays what is contained in register @var{register}.
|
|
428
|
2721 @end deffn
|
|
|
2722
|
|
|
2723 @ignore
|
|
444
|
2724 @deffn Command point-to-register register
|
|
428
|
2725 This command stores both the current location of point and the current
|
|
444
|
2726 buffer in register @var{register} as a marker.
|
|
428
|
2727 @end deffn
|
|
|
2728
|
|
444
|
2729 @deffn Command jump-to-register register
|
|
|
2730 @deffnx Command register-to-point register
|
|
428
|
2731 @comment !!SourceFile register.el
|
|
444
|
2732 This command restores the status recorded in register @var{register}.
|
|
|
2733
|
|
|
2734 If @var{register} contains a marker, it moves point to the position
|
|
|
2735 stored in the marker. Since both the buffer and the location within the
|
|
|
2736 buffer are stored by the @code{point-to-register} function, this command
|
|
|
2737 can switch you to another buffer.
|
|
|
2738
|
|
|
2739 If @var{register} contains a window configuration or a frame configuration.
|
|
428
|
2740 @code{jump-to-register} restores that configuration.
|
|
|
2741 @end deffn
|
|
|
2742 @end ignore
|
|
|
2743
|
|
444
|
2744 @deffn Command insert-register register &optional beforep
|
|
|
2745 This command inserts contents of register @var{register} into the current
|
|
428
|
2746 buffer.
|
|
|
2747
|
|
|
2748 Normally, this command puts point before the inserted text, and the
|
|
|
2749 mark after it. However, if the optional second argument @var{beforep}
|
|
|
2750 is non-@code{nil}, it puts the mark before and point after.
|
|
|
2751 You can pass a non-@code{nil} second argument @var{beforep} to this
|
|
|
2752 function interactively by supplying any prefix argument.
|
|
|
2753
|
|
|
2754 If the register contains a rectangle, then the rectangle is inserted
|
|
|
2755 with its upper left corner at point. This means that text is inserted
|
|
|
2756 in the current line and underneath it on successive lines.
|
|
|
2757
|
|
|
2758 If the register contains something other than saved text (a string) or
|
|
|
2759 a rectangle (a list), currently useless things happen. This may be
|
|
|
2760 changed in the future.
|
|
|
2761 @end deffn
|
|
|
2762
|
|
|
2763 @ignore
|
|
444
|
2764 @deffn Command copy-to-register register start end &optional delete-flag
|
|
428
|
2765 This command copies the region from @var{start} to @var{end} into
|
|
444
|
2766 register @var{register}. If @var{delete-flag} is non-@code{nil}, it deletes
|
|
428
|
2767 the region from the buffer after copying it into the register.
|
|
|
2768 @end deffn
|
|
|
2769
|
|
444
|
2770 @deffn Command prepend-to-register register start end &optional delete-flag
|
|
428
|
2771 This command prepends the region from @var{start} to @var{end} into
|
|
444
|
2772 register @var{register}. If @var{delete-flag} is non-@code{nil}, it deletes
|
|
428
|
2773 the region from the buffer after copying it to the register.
|
|
|
2774 @end deffn
|
|
|
2775
|
|
444
|
2776 @deffn Command append-to-register register start end &optional delete-flag
|
|
428
|
2777 This command appends the region from @var{start} to @var{end} to the
|
|
444
|
2778 text already in register @var{register}. If @var{delete-flag} is
|
|
428
|
2779 non-@code{nil}, it deletes the region from the buffer after copying it
|
|
|
2780 to the register.
|
|
|
2781 @end deffn
|
|
|
2782
|
|
444
|
2783 @deffn Command copy-rectangle-to-register register start end &optional delete-flag
|
|
428
|
2784 This command copies a rectangular region from @var{start} to @var{end}
|
|
444
|
2785 into register @var{register}. If @var{delete-flag} is non-@code{nil}, it
|
|
428
|
2786 deletes the region from the buffer after copying it to the register.
|
|
|
2787 @end deffn
|
|
|
2788
|
|
444
|
2789 @deffn Command window-configuration-to-register register
|
|
428
|
2790 This function stores the window configuration of the selected frame in
|
|
444
|
2791 register @var{register}.
|
|
428
|
2792 @end deffn
|
|
|
2793
|
|
444
|
2794 @deffn Command frame-configuration-to-register register
|
|
428
|
2795 This function stores the current frame configuration in register
|
|
444
|
2796 @var{register}.
|
|
428
|
2797 @end deffn
|
|
|
2798 @end ignore
|
|
|
2799
|
|
|
2800 @node Transposition
|
|
|
2801 @section Transposition of Text
|
|
|
2802
|
|
|
2803 This subroutine is used by the transposition commands.
|
|
|
2804
|
|
|
2805 @defun transpose-regions start1 end1 start2 end2 &optional leave-markers
|
|
|
2806 This function exchanges two nonoverlapping portions of the buffer.
|
|
|
2807 Arguments @var{start1} and @var{end1} specify the bounds of one portion
|
|
|
2808 and arguments @var{start2} and @var{end2} specify the bounds of the
|
|
|
2809 other portion.
|
|
|
2810
|
|
|
2811 Normally, @code{transpose-regions} relocates markers with the transposed
|
|
|
2812 text; a marker previously positioned within one of the two transposed
|
|
|
2813 portions moves along with that portion, thus remaining between the same
|
|
|
2814 two characters in their new position. However, if @var{leave-markers}
|
|
|
2815 is non-@code{nil}, @code{transpose-regions} does not do this---it leaves
|
|
|
2816 all markers unrelocated.
|
|
|
2817 @end defun
|
|
|
2818
|
|
|
2819 @node Change Hooks
|
|
|
2820 @section Change Hooks
|
|
|
2821 @cindex change hooks
|
|
|
2822 @cindex hooks for text changes
|
|
|
2823
|
|
|
2824 These hook variables let you arrange to take notice of all changes in
|
|
|
2825 all buffers (or in a particular buffer, if you make them buffer-local).
|
|
|
2826 @ignore Not in XEmacs
|
|
|
2827 See also @ref{Special Properties}, for how to detect changes to specific
|
|
|
2828 parts of the text.
|
|
|
2829 @end ignore
|
|
|
2830
|
|
|
2831 The functions you use in these hooks should save and restore the match
|
|
|
2832 data if they do anything that uses regular expressions; otherwise, they
|
|
|
2833 will interfere in bizarre ways with the editing operations that call
|
|
|
2834 them.
|
|
|
2835
|
|
|
2836 Buffer changes made while executing the following hooks don't
|
|
|
2837 themselves cause any change hooks to be invoked.
|
|
|
2838
|
|
|
2839 @defvar before-change-functions
|
|
|
2840 This variable holds a list of a functions to call before any buffer
|
|
|
2841 modification. Each function gets two arguments, the beginning and end
|
|
|
2842 of the region that is about to change, represented as integers. The
|
|
|
2843 buffer that is about to change is always the current buffer.
|
|
|
2844 @end defvar
|
|
|
2845
|
|
|
2846 @defvar after-change-functions
|
|
|
2847 This variable holds a list of a functions to call after any buffer
|
|
|
2848 modification. Each function receives three arguments: the beginning and
|
|
|
2849 end of the region just changed, and the length of the text that existed
|
|
|
2850 before the change. (To get the current length, subtract the region
|
|
|
2851 beginning from the region end.) All three arguments are integers. The
|
|
|
2852 buffer that's about to change is always the current buffer.
|
|
|
2853 @end defvar
|
|
|
2854
|
|
|
2855 @defvar before-change-function
|
|
|
2856 This obsolete variable holds one function to call before any buffer
|
|
|
2857 modification (or @code{nil} for no function). It is called just like
|
|
|
2858 the functions in @code{before-change-functions}.
|
|
|
2859 @end defvar
|
|
|
2860
|
|
|
2861 @defvar after-change-function
|
|
|
2862 This obsolete variable holds one function to call after any buffer modification
|
|
|
2863 (or @code{nil} for no function). It is called just like the functions in
|
|
|
2864 @code{after-change-functions}.
|
|
|
2865 @end defvar
|
|
|
2866
|
|
|
2867 @defvar first-change-hook
|
|
|
2868 This variable is a normal hook that is run whenever a buffer is changed
|
|
|
2869 that was previously in the unmodified state.
|
|
|
2870 @end defvar
|
|
|
2871
|
|
|
2872 @node Transformations
|
|
|
2873 @section Textual transformations---MD5 and base64 support
|
|
|
2874 @cindex MD5 digests
|
|
|
2875 @cindex base64
|
|
|
2876
|
|
|
2877 Some textual operations inherently require examining each character in
|
|
|
2878 turn, and performing arithmetic operations on them. Such operations
|
|
|
2879 can, of course, be implemented in Emacs Lisp, but tend to be very slow
|
|
|
2880 for large portions of text or data. This is why some of them are
|
|
|
2881 implemented in C, with an appropriate interface for Lisp programmers.
|
|
|
2882 Examples of algorithms thus provided are MD5 and base64 support.
|
|
|
2883
|
|
|
2884 MD5 is an algorithm for calculating message digests, as described in
|
|
901
|
2885 rfc1321. Given a message of arbitrary length, MD5 produces a 128-bit
|
|
428
|
2886 ``fingerprint'' (``message digest'') corresponding to that message. It
|
|
|
2887 is considered computationally infeasible to produce two messages having
|
|
|
2888 the same MD5 digest, or to produce a message having a prespecified
|
|
|
2889 target digest. MD5 is used heavily by various authentication schemes.
|
|
|
2890
|
|
|
2891 Emacs Lisp interface to MD5 consists of a single function @code{md5}:
|
|
|
2892
|
|
444
|
2893 @defun md5 object &optional start end coding noerror
|
|
428
|
2894 This function returns the MD5 message digest of @var{object}, a buffer
|
|
|
2895 or string.
|
|
|
2896
|
|
|
2897 Optional arguments @var{start} and @var{end} denote positions for
|
|
|
2898 computing the digest of a portion of @var{object}.
|
|
|
2899
|
|
444
|
2900 The optional @var{coding} argument specifies the coding system the text
|
|
|
2901 is to be represented in while computing the digest. If unspecified, it
|
|
|
2902 defaults to the current format of the data, or is guessed.
|
|
|
2903
|
|
|
2904 If @var{noerror} is non-@code{nil}, silently assume binary coding if the
|
|
|
2905 guesswork fails. Normally, an error is signaled in such case.
|
|
|
2906
|
|
|
2907 @var{coding} and @var{noerror} arguments are meaningful only in XEmacsen
|
|
|
2908 with file-coding or Mule support. Otherwise, they are ignored. Some
|
|
|
2909 examples of usage:
|
|
428
|
2910
|
|
|
2911 @example
|
|
|
2912 @group
|
|
|
2913 ;; @r{Calculate the digest of the entire buffer}
|
|
|
2914 (md5 (current-buffer))
|
|
|
2915 @result{} "8842b04362899b1cda8d2d126dc11712"
|
|
|
2916 @end group
|
|
|
2917
|
|
|
2918 @group
|
|
|
2919 ;; @r{Calculate the digest of the current line}
|
|
|
2920 (md5 (current-buffer) (point-at-bol) (point-at-eol))
|
|
|
2921 @result{} "60614d21e9dee27dfdb01fa4e30d6d00"
|
|
|
2922 @end group
|
|
|
2923
|
|
|
2924 @group
|
|
|
2925 ;; @r{Calculate the digest of your name and email address}
|
|
|
2926 (md5 (concat (format "%s <%s>" (user-full-name) user-mail-address)))
|
|
|
2927 @result{} "0a2188c40fd38922d941fe6032fce516"
|
|
|
2928 @end group
|
|
|
2929 @end example
|
|
|
2930 @end defun
|
|
|
2931
|
|
|
2932 Base64 is a portable encoding for arbitrary sequences of octets, in a
|
|
|
2933 form that need not be readable by humans. It uses a 65-character subset
|
|
|
2934 of US-ASCII, as described in rfc2045. Base64 is used by MIME to encode
|
|
|
2935 binary bodies, and to encode binary characters in message headers.
|
|
|
2936
|
|
|
2937 The Lisp interface to base64 consists of four functions:
|
|
|
2938
|
|
444
|
2939 @deffn Command base64-encode-region start end &optional no-line-break
|
|
|
2940 This function encodes the region between @var{start} and @var{end} of the
|
|
|
2941 current buffer to base64 format. This means that the original region is
|
|
428
|
2942 deleted, and replaced with its base64 equivalent.
|
|
|
2943
|
|
|
2944 Normally, encoded base64 output is multi-line, with 76-character lines.
|
|
444
|
2945 If @var{no-line-break} is non-@code{nil}, newlines will not be inserted,
|
|
428
|
2946 resulting in single-line output.
|
|
|
2947
|
|
|
2948 Mule note: you should make sure that you convert the multibyte
|
|
|
2949 characters (those that do not fit into 0--255 range) to something else,
|
|
|
2950 because they cannot be meaningfully converted to base64. If the
|
|
|
2951 @code{base64-encode-region} encounters such characters, it will signal
|
|
|
2952 an error.
|
|
|
2953
|
|
|
2954 @code{base64-encode-region} returns the length of the encoded text.
|
|
|
2955
|
|
|
2956 @example
|
|
|
2957 @group
|
|
|
2958 ;; @r{Encode the whole buffer in base64}
|
|
|
2959 (base64-encode-region (point-min) (point-max))
|
|
|
2960 @end group
|
|
|
2961 @end example
|
|
|
2962
|
|
|
2963 The function can also be used interactively, in which case it works on
|
|
|
2964 the currently active region.
|
|
444
|
2965 @end deffn
|
|
|
2966
|
|
|
2967 @defun base64-encode-string string &optional no-line-break
|
|
428
|
2968 This function encodes @var{string} to base64, and returns the encoded
|
|
|
2969 string.
|
|
|
2970
|
|
444
|
2971 Normally, encoded base64 output is multi-line, with 76-character lines.
|
|
|
2972 If @var{no-line-break} is non-@code{nil}, newlines will not be inserted,
|
|
|
2973 resulting in single-line output.
|
|
|
2974
|
|
428
|
2975 For Mule, the same considerations apply as for
|
|
|
2976 @code{base64-encode-region}.
|
|
|
2977
|
|
|
2978 @example
|
|
|
2979 @group
|
|
|
2980 (base64-encode-string "fubar")
|
|
|
2981 @result{} "ZnViYXI="
|
|
|
2982 @end group
|
|
|
2983 @end example
|
|
|
2984 @end defun
|
|
|
2985
|
|
444
|
2986 @deffn Command base64-decode-region start end
|
|
|
2987 This function decodes the region between @var{start} and @var{end} of the
|
|
428
|
2988 current buffer. The region should be in base64 encoding.
|
|
|
2989
|
|
|
2990 If the region was decoded correctly, @code{base64-decode-region} returns
|
|
444
|
2991 the length of the decoded region. If the decoding failed, @code{nil} is
|
|
428
|
2992 returned.
|
|
|
2993
|
|
|
2994 @example
|
|
|
2995 @group
|
|
|
2996 ;; @r{Decode a base64 buffer, and replace it with the decoded version}
|
|
|
2997 (base64-decode-region (point-min) (point-max))
|
|
|
2998 @end group
|
|
|
2999 @end example
|
|
444
|
3000 @end deffn
|
|
428
|
3001
|
|
|
3002 @defun base64-decode-string string
|
|
|
3003 This function decodes @var{string} to base64, and returns the decoded
|
|
|
3004 string. @var{string} should be valid base64-encoded text.
|
|
|
3005
|
|
|
3006 If encoding was not possible, @code{nil} is returned.
|
|
|
3007
|
|
|
3008 @example
|
|
|
3009 @group
|
|
|
3010 (base64-decode-string "ZnViYXI=")
|
|
|
3011 @result{} "fubar"
|
|
|
3012 @end group
|
|
|
3013
|
|
|
3014 @group
|
|
|
3015 (base64-decode-string "totally bogus")
|
|
|
3016 @result{} nil
|
|
|
3017 @end group
|
|
|
3018 @end example
|
|
|
3019 @end defun
|
