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1
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2 @node Programs, Running, Text, Top
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3 @chapter Editing Programs
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4 @cindex Lisp
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5 @cindex C
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6
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7 Emacs has many commands designed to understand the syntax of programming
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8 languages such as Lisp and C. These commands can:
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9
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10 @itemize @bullet
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11 @item
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12 Move over or kill balanced expressions or @dfn{sexps} (@pxref{Lists}).
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13 @item
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14 Move over or mark top-level balanced expressions (@dfn{defuns}, in Lisp;
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15 functions, in C).
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16 @item
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17 Show how parentheses balance (@pxref{Matching}).
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18 @item
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19 Insert, kill, or align comments (@pxref{Comments}).
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20 @item
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21 Follow the usual indentation conventions of the language
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22 (@pxref{Grinding}).
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23 @end itemize
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24
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25 The commands available for words, sentences, and paragraphs are useful in
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26 editing code even though their canonical application is for editing human
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27 language text. Most symbols contain words (@pxref{Words}); sentences can
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28 be found in strings and comments (@pxref{Sentences}). Paragraphs per se
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29 are not present in code, but the paragraph commands are useful anyway,
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30 because Lisp mode and C mode define paragraphs to begin and end at blank
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31 lines (@pxref{Paragraphs}). Judicious use of blank lines to make the
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32 program clearer also provides interesting chunks of text for the
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33 paragraph commands to work on.
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34
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35 The selective display feature is useful for looking at the overall
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36 structure of a function (@pxref{Selective Display}). This feature causes
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37 only the lines that are indented less than a specified amount to appear
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38 on the screen.
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39
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40 @menu
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41 * Program Modes:: Major modes for editing programs.
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42 * Lists:: Expressions with balanced parentheses.
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43 There are editing commands to operate on them.
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44 * Defuns:: Each program is made up of separate functions.
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45 There are editing commands to operate on them.
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46 * Grinding:: Adjusting indentation to show the nesting.
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47 * Matching:: Insertion of a close-delimiter flashes matching open.
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442
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48 * Comments:: Inserting, filling and aligning comments.
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49 * Balanced Editing:: Inserting two matching parentheses at once, etc.
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50 * Lisp Completion:: Completion on symbol names in Lisp code.
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51 * Documentation:: Getting documentation of functions you plan to call.
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52 * Change Log:: Maintaining a change history for your program.
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53 * Tags:: Go direct to any function in your program in one
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54 command. Tags remembers which file it is in.
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55 * Fortran:: Fortran mode and its special features.
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56 * Asm Mode:: Asm mode and its special features.
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57 @end menu
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58
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59 @node Program Modes, Lists, Programs, Programs
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60 @section Major Modes for Programming Languages
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61
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62 @cindex Lisp mode
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63 @cindex C mode
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64 @cindex Scheme mode
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65 Emacs has several major modes for the programming languages Lisp, Scheme (a
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66 variant of Lisp), C, Fortran, and Muddle. Ideally, a major mode should be
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67 implemented for each programming language you might want to edit with
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68 Emacs; but often the mode for one language can serve for other
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69 syntactically similar languages. The language modes that exist are those
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70 that someone decided to take the trouble to write.
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71
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72 There are several variants of Lisp mode, which differ in the way they
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73 interface to Lisp execution. @xref{Lisp Modes}.
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74
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75 Each of the programming language modes defines the @key{TAB} key to run
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76 an indentation function that knows the indentation conventions of that
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77 language and updates the current line's indentation accordingly. For
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78 example, in C mode @key{TAB} is bound to @code{c-indent-line}. @key{LFD}
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79 is normally defined to do @key{RET} followed by @key{TAB}; thus it, too,
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80 indents in a mode-specific fashion.
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81
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82 @kindex DEL
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83 @findex backward-delete-char-untabify
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84 In most programming languages, indentation is likely to vary from line to
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85 line. So the major modes for those languages rebind @key{DEL} to treat a
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86 tab as if it were the equivalent number of spaces (using the command
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87 @code{backward-delete-char-untabify}). This makes it possible to rub out
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88 indentation one column at a time without worrying whether it is made up of
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89 spaces or tabs. In these modes, use @kbd{C-b C-d} to delete a tab
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90 character before point.
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91
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92 Programming language modes define paragraphs to be separated only by
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93 blank lines, so that the paragraph commands remain useful. Auto Fill mode,
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94 if enabled in a programming language major mode, indents the new lines
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95 which it creates.
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96
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97 @cindex mode hook
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98 @vindex c-mode-hook
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99 @vindex lisp-mode-hook
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100 @vindex emacs-lisp-mode-hook
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101 @vindex lisp-interaction-mode-hook
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102 @vindex scheme-mode-hook
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103 @vindex muddle-mode-hook
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104 Turning on a major mode calls a user-supplied function called the
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105 @dfn{mode hook}, which is the value of a Lisp variable. For example,
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106 turning on C mode calls the value of the variable @code{c-mode-hook} if
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107 that value exists and is non-@code{nil}. Mode hook variables for other
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108 programming language modes include @code{lisp-mode-hook},
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109 @code{emacs-lisp-mode-hook}, @code{lisp-interaction-mode-hook},
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110 @code{scheme-mode-hook}, and @code{muddle-mode-hook}. The mode hook
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111 function receives no arguments.@refill
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112
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113 @node Lists, Defuns, Program Modes, Programs
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114 @section Lists and Sexps
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115
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116 @cindex Control-Meta
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117 By convention, Emacs keys for dealing with balanced expressions are
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118 usually @kbd{Control-Meta-} characters. They tend to be analogous in
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119 function to their @kbd{Control-} and @kbd{Meta-} equivalents. These commands
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120 are usually thought of as pertaining to expressions in programming
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121 languages, but can be useful with any language in which some sort of
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122 parentheses exist (including English).
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123
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124 @cindex list
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125 @cindex sexp
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126 @cindex expression
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127 The commands fall into two classes. Some commands deal only with
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128 @dfn{lists} (parenthetical groupings). They see nothing except
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129 parentheses, brackets, braces (depending on what must balance in the
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130 language you are working with), and escape characters that might be used
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131 to quote those.
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132
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133 The other commands deal with expressions or @dfn{sexps}. The word `sexp'
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134 is derived from @dfn{s-expression}, the term for a symbolic expression in
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135 Lisp. In Emacs, the notion of `sexp' is not limited to Lisp. It
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136 refers to an expression in the language your program is written in.
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137 Each programming language has its own major mode, which customizes the
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138 syntax tables so that expressions in that language count as sexps.
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139
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140 Sexps typically include symbols, numbers, and string constants, as well
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141 as anything contained in parentheses, brackets, or braces.
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142
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143 In languages that use prefix and infix operators, such as C, it is not
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144 possible for all expressions to be sexps. For example, C mode does not
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145 recognize @samp{foo + bar} as an sexp, even though it @i{is} a C expression;
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146 it recognizes @samp{foo} as one sexp and @samp{bar} as another, with the
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147 @samp{+} as punctuation between them. This is a fundamental ambiguity:
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148 both @samp{foo + bar} and @samp{foo} are legitimate choices for the sexp to
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149 move over if point is at the @samp{f}. Note that @samp{(foo + bar)} is a
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150 sexp in C mode.
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151
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152 Some languages have obscure forms of syntax for expressions that nobody
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153 has bothered to make Emacs understand properly.
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154
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155 @c doublewidecommands
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156 @table @kbd
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157 @item C-M-f
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158 Move forward over an sexp (@code{forward-sexp}).
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159 @item C-M-b
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160 Move backward over an sexp (@code{backward-sexp}).
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161 @item C-M-k
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162 Kill sexp forward (@code{kill-sexp}).
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163 @item C-M-u
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164 Move up and backward in list structure (@code{backward-up-list}).
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165 @item C-M-d
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166 Move down and forward in list structure (@code{down-list}).
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167 @item C-M-n
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168 Move forward over a list (@code{forward-list}).
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169 @item C-M-p
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170 Move backward over a list (@code{backward-list}).
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171 @item C-M-t
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172 Transpose expressions (@code{transpose-sexps}).
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173 @item C-M-@@
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174 Put mark after following expression (@code{mark-sexp}).
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175 @end table
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176
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177 @kindex C-M-f
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178 @kindex C-M-b
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179 @findex forward-sexp
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180 @findex backward-sexp
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181 To move forward over an sexp, use @kbd{C-M-f} (@code{forward-sexp}). If
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182 the first significant character after point is an opening delimiter
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183 (@samp{(} in Lisp; @samp{(}, @samp{[}, or @samp{@{} in C), @kbd{C-M-f}
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184 moves past the matching closing delimiter. If the character begins a
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185 symbol, string, or number, @kbd{C-M-f} moves over that. If the character
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186 after point is a closing delimiter, @kbd{C-M-f} just moves past it. (This
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187 last is not really moving across an sexp; it is an exception which is
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188 included in the definition of @kbd{C-M-f} because it is as useful a
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189 behavior as anyone can think of for that situation.)@refill
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190
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191 The command @kbd{C-M-b} (@code{backward-sexp}) moves backward over a
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192 sexp. The detailed rules are like those above for @kbd{C-M-f}, but with
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193 directions reversed. If there are any prefix characters (single quote,
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194 back quote, and comma, in Lisp) preceding the sexp, @kbd{C-M-b} moves back
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195 over them as well.
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196
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197 @kbd{C-M-f} or @kbd{C-M-b} with an argument repeats that operation the
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198 specified number of times; with a negative argument, it moves in the
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199 opposite direction.
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200
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201 In languages such as C where the comment-terminator can be recognized,
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202 the sexp commands move across comments as if they were whitespace. In
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203 Lisp and other languages where comments run until the end of a line, it
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204 is very difficult to ignore comments when parsing backwards; therefore,
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205 in such languages the sexp commands treat the text of comments as if it
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206 were code.
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207
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208 @kindex C-M-k
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209 @findex kill-sexp
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210 Killing an sexp at a time can be done with @kbd{C-M-k} (@code{kill-sexp}).
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211 @kbd{C-M-k} kills the characters that @kbd{C-M-f} would move over.
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212
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213 @kindex C-M-n
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214 @kindex C-M-p
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215 @findex forward-list
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216 @findex backward-list
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217 The @dfn{list commands}, @kbd{C-M-n} (@code{forward-list}) and
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218 @kbd{C-M-p} (@code{backward-list}), move over lists like the sexp
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219 commands but skip over any number of other kinds of sexps (symbols,
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220 strings, etc). In some situations, these commands are useful because
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221 they usually ignore comments, since the comments usually do not contain
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222 any lists.@refill
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223
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224 @kindex C-M-u
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225 @kindex C-M-d
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226 @findex backward-up-list
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227 @findex down-list
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228 @kbd{C-M-n} and @kbd{C-M-p} stay at the same level in parentheses, when
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229 that is possible. To move @i{up} one (or @var{n}) levels, use @kbd{C-M-u}
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230 (@code{backward-up-list}).
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231 @kbd{C-M-u} moves backward up past one unmatched opening delimiter. A
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232 positive argument serves as a repeat count; a negative argument reverses
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233 direction of motion and also requests repetition, so it moves forward and
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234 up one or more levels.@refill
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235
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236 To move @i{down} in list structure, use @kbd{C-M-d}
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237 (@code{down-list}). In Lisp mode, where @samp{(} is the only opening
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238 delimiter, this is nearly the same as searching for a @samp{(}. An
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239 argument specifies the number of levels of parentheses to go down.
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240
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241 @cindex transposition
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242 @kindex C-M-t
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243 @findex transpose-sexps
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244 @kbd{C-M-t} (@code{transpose-sexps}) drags the previous sexp across
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245 the next one. An argument serves as a repeat count, and a negative
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246 argument drags backwards (thus canceling out the effect of @kbd{C-M-t} with
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247 a positive argument). An argument of zero, rather than doing nothing,
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248 transposes the sexps ending after point and the mark.
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249
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250 @kindex C-M-@@
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251 @findex mark-sexp
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252 To make the region be the next sexp in the buffer, use @kbd{C-M-@@}
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253 (@code{mark-sexp}) which sets the mark at the same place that
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254 @kbd{C-M-f} would move to. @kbd{C-M-@@} takes arguments like
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255 @kbd{C-M-f}. In particular, a negative argument is useful for putting
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256 the mark at the beginning of the previous sexp.
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257
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258 The list and sexp commands' understanding of syntax is completely
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259 controlled by the syntax table. Any character can, for example, be
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260 declared to be an opening delimiter and act like an open parenthesis.
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261 @xref{Syntax}.
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262
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263 @node Defuns, Grinding, Lists, Programs
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264 @section Defuns
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265 @cindex defuns
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266
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267 In Emacs, a parenthetical grouping at the top level in the buffer is
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268 called a @dfn{defun}. The name derives from the fact that most
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269 top-level lists in Lisp are instances of the special form
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270 @code{defun}, but Emacs calls any top-level parenthetical
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271 grouping counts a defun regardless of its contents or
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272 the programming language. For example, in C, the body of a
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273 function definition is a defun.
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274
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275 @c doublewidecommands
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276 @table @kbd
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277 @item C-M-a
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278 Move to beginning of current or preceding defun
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279 (@code{beginning-of-defun}).
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280 @item C-M-e
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281 Move to end of current or following defun (@code{end-of-defun}).
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282 @item C-M-h
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283 Put region around whole current or following defun (@code{mark-defun}).
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284 @end table
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285
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286 @kindex C-M-a
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287 @kindex C-M-e
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288 @kindex C-M-h
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289 @findex beginning-of-defun
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290 @findex end-of-defun
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291 @findex mark-defun
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292 The commands to move to the beginning and end of the current defun are
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293 @kbd{C-M-a} (@code{beginning-of-defun}) and @kbd{C-M-e} (@code{end-of-defun}).
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294
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295 To operate on the current defun, use @kbd{C-M-h} (@code{mark-defun})
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296 which puts point at the beginning and the mark at the end of the current
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297 or next defun. This is the easiest way to prepare for moving the defun
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298 to a different place. In C mode, @kbd{C-M-h} runs the function
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299 @code{mark-c-function}, which is almost the same as @code{mark-defun},
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300 but which backs up over the argument declarations, function name, and
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301 returned data type so that the entire C function is inside the region.
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302
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303 @findex compile-defun
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304 To compile and evaluate the current defun, use @kbd{M-x compile-defun}.
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305 This function prints the results in the minibuffer. If you include an
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306 argument, it inserts the value in the current buffer after the defun.
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307
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308 Emacs assumes that any open-parenthesis found in the leftmost column is
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309 the start of a defun. Therefore, @i{never put an open-parenthesis at the
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310 left margin in a Lisp file unless it is the start of a top level list.
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311 Never put an open-brace or other opening delimiter at the beginning of a
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312 line of C code unless it starts the body of a function.} The most likely
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313 problem case is when you want an opening delimiter at the start of a line
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314 inside a string. To avoid trouble, put an escape character (@samp{\} in C
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315 and Emacs Lisp, @samp{/} in some other Lisp dialects) before the opening
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316 delimiter. It will not affect the contents of the string.
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317
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318 The original Emacs found defuns by moving upward a
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319 level of parentheses until there were no more levels to go up. This
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320 required scanning back to the beginning of the buffer for every
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321 function. To speed this up, Emacs was changed to assume
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322 that any @samp{(} (or other character assigned the syntactic class of
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323 opening-delimiter) at the left margin is the start of a defun. This
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324 heuristic is nearly always right; however, it mandates the convention
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325 described above.
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326
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327 @node Grinding, Matching, Defuns, Programs
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328 @section Indentation for Programs
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329 @cindex indentation
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330 @cindex grinding
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331
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332 The best way to keep a program properly indented (``ground'') is to
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333 use Emacs to re-indent it as you change the program. Emacs has commands
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334 to indent properly either a single line, a specified number of lines, or
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335 all of the lines inside a single parenthetical grouping.
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336
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337 @menu
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338 * Basic Indent::
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339 * Multi-line Indent:: Commands to reindent many lines at once.
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340 * Lisp Indent:: Specifying how each Lisp function should be indented.
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341 * C Indent:: Choosing an indentation style for C code.
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342 @end menu
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343
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344 @node Basic Indent, Multi-line Indent, Grinding, Grinding
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345 @subsection Basic Program Indentation Commands
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346
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347 @c WideCommands
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348 @table @kbd
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349 @item @key{TAB}
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350 Adjust indentation of current line.
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351 @item @key{LFD}
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352 Equivalent to @key{RET} followed by @key{TAB} (@code{newline-and-indent}).
|
|
|
353 @end table
|
|
|
354
|
|
|
355 @kindex TAB
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|
|
356 @findex c-indent-line
|
|
|
357 @findex lisp-indent-line
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|
|
358 The basic indentation command is @key{TAB}, which gives the current
|
|
|
359 line the correct indentation as determined from the previous lines. The
|
|
|
360 function that @key{TAB} runs depends on the major mode; it is
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|
|
361 @code{lisp-indent-line} in Lisp mode, @code{c-indent-line} in C mode,
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|
|
362 etc. These functions understand different syntaxes for different
|
|
|
363 languages, but they all do about the same thing. @key{TAB} in any
|
|
|
364 programming language major mode inserts or deletes whitespace at the
|
|
|
365 beginning of the current line, independent of where point is in the
|
|
|
366 line. If point is inside the whitespace at the beginning of the line,
|
|
|
367 @key{TAB} leaves it at the end of that whitespace; otherwise, @key{TAB}
|
|
|
368 leaves point fixed with respect to the characters around it.
|
|
|
369
|
|
|
370 Use @kbd{C-q @key{TAB}} to insert a tab at point.
|
|
|
371
|
|
|
372 @kindex LFD
|
|
|
373 @findex newline-and-indent
|
|
|
374 When entering a large amount of new code, use @key{LFD}
|
|
|
375 (@code{newline-and-indent}), which is equivalent to a @key{RET} followed
|
|
|
376 by a @key{TAB}. @key{LFD} creates a blank line, then gives it the
|
|
|
377 appropriate indentation.
|
|
|
378
|
|
|
379 @key{TAB} indents the second and following lines of the body of a
|
|
|
380 parenthetical grouping each under the preceding one; therefore, if you
|
|
|
381 alter one line's indentation to be nonstandard, the lines below tend
|
|
|
382 to follow it. This is the right behavior in cases where the standard
|
|
|
383 result of @key{TAB} does not look good.
|
|
|
384
|
|
|
385 Remember that Emacs assumes that an open-parenthesis, open-brace, or
|
|
|
386 other opening delimiter at the left margin (including the indentation
|
|
|
387 routines) is the start of a function. You should therefore never have
|
|
|
388 an opening delimiter in column zero that is not the beginning of a
|
|
|
389 function, not even inside a string. This restriction is vital for
|
|
|
390 making the indentation commands fast. @xref{Defuns}, for more
|
|
|
391 information on this behavior.
|
|
|
392
|
|
|
393 @node Multi-line Indent, Lisp Indent, Basic Indent, Grinding
|
|
|
394 @subsection Indenting Several Lines
|
|
|
395
|
|
|
396 Several commands are available to re-indent several lines of code
|
|
|
397 which have been altered or moved to a different level in a list
|
|
|
398 structure.
|
|
|
399
|
|
|
400
|
|
|
401 @table @kbd
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|
|
402 @item C-M-q
|
|
|
403 Re-indent all the lines within one list (@code{indent-sexp}).
|
|
|
404 @item C-u @key{TAB}
|
|
|
405 Shift an entire list rigidly sideways so that its first line
|
|
|
406 is properly indented.
|
|
|
407 @item C-M-\
|
|
|
408 Re-indent all lines in the region (@code{indent-region}).
|
|
|
409 @end table
|
|
|
410
|
|
|
411 @kindex C-M-q
|
|
|
412 @findex indent-sexp
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|
|
413 @findex indent-c-exp
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|
|
414 To re-indent the contents of a single list, position point before the
|
|
|
415 beginning of it and type @kbd{C-M-q}. This key is bound to
|
|
|
416 @code{indent-sexp} in Lisp mode, @code{indent-c-exp} in C mode, and
|
|
|
417 bound to other suitable functions in other modes. The indentation of
|
|
|
418 the line the sexp starts on is not changed; therefore, only the relative
|
|
|
419 indentation within the list, and not its position, is changed. To
|
|
|
420 correct the position as well, type a @key{TAB} before @kbd{C-M-q}.
|
|
|
421
|
|
|
422 @kindex C-u TAB
|
|
|
423 If the relative indentation within a list is correct but the
|
|
|
424 indentation of its beginning is not, go to the line on which the list
|
|
|
425 begins and type @kbd{C-u @key{TAB}}. When you give @key{TAB} a numeric
|
|
|
426 argument, it moves all the lines in the group, starting on the current
|
|
|
427 line, sideways the same amount that the current line moves. The command
|
|
|
428 does not move lines that start inside strings, or C
|
|
|
429 preprocessor lines when in C mode.
|
|
|
430
|
|
|
431 @kindex C-M-\
|
|
|
432 @findex indent-region
|
|
|
433 Another way to specify a range to be re-indented is with point and
|
|
|
434 mark. The command @kbd{C-M-\} (@code{indent-region}) applies @key{TAB}
|
|
|
435 to every line whose first character is between point and mark.
|
|
|
436
|
|
|
437 @node Lisp Indent, C Indent, Multi-line Indent, Grinding
|
|
|
438 @subsection Customizing Lisp Indentation
|
|
|
439 @cindex customization
|
|
|
440
|
|
|
441 The indentation pattern for a Lisp expression can depend on the function
|
|
|
442 called by the expression. For each Lisp function, you can choose among
|
|
|
443 several predefined patterns of indentation, or define an arbitrary one with
|
|
|
444 a Lisp program.
|
|
|
445
|
|
|
446 The standard pattern of indentation is as follows: the second line of the
|
|
|
447 expression is indented under the first argument, if that is on the same
|
|
|
448 line as the beginning of the expression; otherwise, the second line is
|
|
|
449 indented underneath the function name. Each following line is indented
|
|
|
450 under the previous line whose nesting depth is the same.
|
|
|
451
|
|
|
452 @vindex lisp-indent-offset
|
|
|
453 If the variable @code{lisp-indent-offset} is non-@code{nil}, it overrides
|
|
|
454 the usual indentation pattern for the second line of an expression, so that
|
|
|
455 such lines are always indented @code{lisp-indent-offset} more columns than
|
|
|
456 the containing list.
|
|
|
457
|
|
|
458 @vindex lisp-body-indention
|
|
|
459 Certain functions override the standard pattern. Functions
|
|
|
460 whose names start with @code{def} always indent the second line by
|
|
|
461 @code{lisp-body-indention} extra columns beyond the open-parenthesis
|
|
|
462 starting the expression.
|
|
|
463
|
|
|
464 Individual functions can override the standard pattern in various
|
|
|
465 ways, according to the @code{lisp-indent-function} property of the
|
|
|
466 function name. (Note: @code{lisp-indent-function} was formerly called
|
|
|
467 @code{lisp-indent-hook}). There are four possibilities for this
|
|
|
468 property:
|
|
|
469
|
|
|
470 @table @asis
|
|
|
471 @item @code{nil}
|
|
|
472 This is the same as no property; the standard indentation pattern is used.
|
|
|
473 @item @code{defun}
|
|
|
474 The pattern used for function names that start with @code{def} is used for
|
|
|
475 this function also.
|
|
|
476 @item a number, @var{number}
|
|
|
477 The first @var{number} arguments of the function are
|
|
|
478 @dfn{distinguished} arguments; the rest are considered the @dfn{body}
|
|
|
479 of the expression. A line in the expression is indented according to
|
|
|
480 whether the first argument on it is distinguished or not. If the
|
|
|
481 argument is part of the body, the line is indented @code{lisp-body-indent}
|
|
|
482 more columns than the open-parenthesis starting the containing
|
|
|
483 expression. If the argument is distinguished and is either the first
|
|
|
484 or second argument, it is indented @i{twice} that many extra columns.
|
|
|
485 If the argument is distinguished and not the first or second argument,
|
|
|
486 the standard pattern is followed for that line.
|
|
|
487 @item a symbol, @var{symbol}
|
|
|
488 @var{symbol} should be a function name; that function is called to
|
|
|
489 calculate the indentation of a line within this expression. The
|
|
|
490 function receives two arguments:
|
|
|
491 @table @asis
|
|
|
492 @item @var{state}
|
|
|
493 The value returned by @code{parse-partial-sexp} (a Lisp primitive for
|
|
|
494 indentation and nesting computation) when it parses up to the
|
|
|
495 beginning of this line.
|
|
|
496 @item @var{pos}
|
|
|
497 The position at which the line being indented begins.
|
|
|
498 @end table
|
|
|
499 @noindent
|
|
|
500 It should return either a number, which is the number of columns of
|
|
|
501 indentation for that line, or a list whose first element is such a
|
|
|
502 number. The difference between returning a number and returning a list
|
|
|
503 is that a number says that all following lines at the same nesting level
|
|
|
504 should be indented just like this one; a list says that following lines
|
|
|
505 might call for different indentations. This makes a difference when the
|
|
|
506 indentation is computed by @kbd{C-M-q}; if the value is a number,
|
|
|
507 @kbd{C-M-q} need not recalculate indentation for the following lines
|
|
|
508 until the end of the list.
|
|
|
509 @end table
|
|
|
510
|
|
|
511 @node C Indent, , Lisp Indent, Grinding
|
|
|
512 @subsection Customizing C Indentation
|
|
|
513
|
|
|
514 Two variables control which commands perform C indentation and when.
|
|
|
515
|
|
|
516 @vindex c-auto-newline
|
|
|
517 If @code{c-auto-newline} is non-@code{nil}, newlines are inserted both
|
|
|
518 before and after braces that you insert and after colons and semicolons.
|
|
|
519 Correct C indentation is done on all the lines that are made this way.
|
|
|
520
|
|
|
521 @vindex c-tab-always-indent
|
|
|
522 If @code{c-tab-always-indent} is non-@code{nil}, the @key{TAB} command
|
|
|
523 in C mode does indentation only if point is at the left margin or within
|
|
|
524 the line's indentation. If there is non-whitespace to the left of point,
|
|
|
525 @key{TAB} just inserts a tab character in the buffer. Normally,
|
|
|
526 this variable is @code{nil}, and @key{TAB} always reindents the current line.
|
|
|
527
|
|
|
528 C does not have anything analogous to particular function names for which
|
|
|
529 special forms of indentation are desirable. However, it has a different
|
|
|
530 need for customization facilities: many different styles of C indentation
|
|
|
531 are in common use.
|
|
|
532
|
|
|
533 There are six variables you can set to control the style that Emacs C
|
|
|
534 mode will use.
|
|
|
535
|
|
|
536 @table @code
|
|
|
537 @item c-indent-level
|
|
|
538 Indentation of C statements within surrounding block. The surrounding
|
|
|
539 block's indentation is the indentation of the line on which the
|
|
|
540 open-brace appears.
|
|
|
541 @item c-continued-statement-offset
|
|
|
542 Extra indentation given to a substatement, such as the then-clause of
|
|
|
543 an @code{if} or body of a @code{while}.
|
|
|
544 @item c-brace-offset
|
|
|
545 Extra indentation for lines that start with an open brace.
|
|
|
546 @item c-brace-imaginary-offset
|
|
|
547 An open brace following other text is treated as if it were this far
|
|
|
548 to the right of the start of its line.
|
|
|
549 @item c-argdecl-indent
|
|
|
550 Indentation level of declarations of C function arguments.
|
|
|
551 @item c-label-offset
|
|
|
552 Extra indentation for a line that is a label, case, or default.
|
|
|
553 @end table
|
|
|
554
|
|
|
555 @vindex c-indent-level
|
|
|
556 The variable @code{c-indent-level} controls the indentation for C
|
|
|
557 statements with respect to the surrounding block. In the example:
|
|
|
558
|
|
|
559 @example
|
|
|
560 @{
|
|
|
561 foo ();
|
|
|
562 @end example
|
|
|
563
|
|
|
564 @noindent
|
|
|
565 the difference in indentation between the lines is @code{c-indent-level}.
|
|
|
566 Its standard value is 2.
|
|
|
567
|
|
|
568 If the open-brace beginning the compound statement is not at the beginning
|
|
|
569 of its line, the @code{c-indent-level} is added to the indentation of the
|
|
|
570 line, not the column of the open-brace. For example,
|
|
|
571
|
|
|
572 @example
|
|
|
573 if (losing) @{
|
|
|
574 do_this ();
|
|
|
575 @end example
|
|
|
576
|
|
|
577 @noindent
|
|
|
578 One popular indentation style is that which results from setting
|
|
|
579 @code{c-indent-level} to 8 and putting open-braces at the end of a line
|
|
|
580 in this way. Another popular style prefers to put the open-brace on a
|
|
|
581 separate line.
|
|
|
582
|
|
|
583 @vindex c-brace-imaginary-offset
|
|
|
584 In fact, the value of the variable @code{c-brace-imaginary-offset} is
|
|
|
585 also added to the indentation of such a statement. Normally this variable
|
|
|
586 is zero. Think of this variable as the imaginary position of the open
|
|
|
587 brace, relative to the first non-blank character on the line. By setting
|
|
|
588 the variable to 4 and @code{c-indent-level} to 0, you can get this style:
|
|
|
589
|
|
|
590 @example
|
|
|
591 if (x == y) @{
|
|
|
592 do_it ();
|
|
|
593 @}
|
|
|
594 @end example
|
|
|
595
|
|
|
596 When @code{c-indent-level} is zero, the statements inside most braces
|
|
|
597 line up exactly under the open brace. An exception are braces in column
|
|
|
598 zero, like those surrounding a function's body. The statements inside
|
|
|
599 those braces are not placed at column zero. Instead,
|
|
|
600 @code{c-brace-offset} and @code{c-continued-statement-offset} (see
|
|
|
601 below) are added to produce a typical offset between brace levels, and
|
|
|
602 the statements are indented that far.
|
|
|
603
|
|
|
604 @vindex c-continued-statement-offset
|
|
|
605 @code{c-continued-statement-offset} controls the extra indentation for
|
|
|
606 a line that starts within a statement (but not within parentheses or
|
|
|
607 brackets). These lines are usually statements inside other statements,
|
|
|
608 like the then-clauses of @code{if} statements and the bodies of
|
|
|
609 @code{while} statements. The @code{c-continued-statement-offset}
|
|
|
610 parameter determines the difference in indentation between the two lines in:
|
|
|
611
|
|
|
612 @example
|
|
|
613 if (x == y)
|
|
|
614 do_it ();
|
|
|
615 @end example
|
|
|
616
|
|
|
617 @noindent
|
|
|
618 The default value for @code{c-continued-statement-offset} is 2. Some
|
|
|
619 popular indentation styles correspond to a value of zero for
|
|
|
620 @code{c-continued-statement-offset}.
|
|
|
621
|
|
|
622 @vindex c-brace-offset
|
|
|
623 @code{c-brace-offset} is the extra indentation given to a line that
|
|
|
624 starts with an open-brace. Its standard value is zero;
|
|
|
625 compare:
|
|
|
626
|
|
|
627 @example
|
|
|
628 if (x == y)
|
|
|
629 @{
|
|
|
630 @end example
|
|
|
631
|
|
|
632 @noindent
|
|
|
633 with:
|
|
|
634
|
|
|
635 @example
|
|
|
636 if (x == y)
|
|
|
637 do_it ();
|
|
|
638 @end example
|
|
|
639
|
|
|
640 @noindent
|
|
|
641 If you set @code{c-brace-offset} to 4, the first example becomes:
|
|
|
642
|
|
|
643 @example
|
|
|
644 if (x == y)
|
|
|
645 @{
|
|
|
646 @end example
|
|
|
647
|
|
|
648 @vindex c-argdecl-indent
|
|
|
649 @code{c-argdecl-indent} controls the indentation of declarations of the
|
|
|
650 arguments of a C function. It is absolute: argument declarations receive
|
|
|
651 exactly @code{c-argdecl-indent} spaces. The standard value is 5 and
|
|
|
652 results in code like this:
|
|
|
653
|
|
|
654 @example
|
|
|
655 char *
|
|
|
656 index (string, char)
|
|
|
657 char *string;
|
|
|
658 int char;
|
|
|
659 @end example
|
|
|
660
|
|
|
661 @vindex c-label-offset
|
|
|
662 @code{c-label-offset} is the extra indentation given to a line that
|
|
|
663 contains a label, a case statement, or a @code{default:} statement. Its
|
|
|
664 standard value is @minus{}2 and results in code like this:
|
|
|
665
|
|
|
666 @example
|
|
|
667 switch (c)
|
|
|
668 @{
|
|
|
669 case 'x':
|
|
|
670 @end example
|
|
|
671
|
|
|
672 @noindent
|
|
|
673 If @code{c-label-offset} were zero, the same code would be indented as:
|
|
|
674
|
|
|
675 @example
|
|
|
676 switch (c)
|
|
|
677 @{
|
|
|
678 case 'x':
|
|
|
679 @end example
|
|
|
680
|
|
|
681 @noindent
|
|
|
682 This example assumes that the other variables above also have their
|
|
|
683 default values.
|
|
|
684
|
|
|
685 Using the indentation style produced by the default settings of the
|
|
|
686 variables just discussed and putting open braces on separate lines
|
|
|
687 produces clear and readable files. For an example, look at any of the C
|
|
|
688 source files of XEmacs.
|
|
|
689
|
|
|
690 @node Matching, Comments, Grinding, Programs
|
|
|
691 @section Automatic Display of Matching Parentheses
|
|
|
692 @cindex matching parentheses
|
|
|
693 @cindex parentheses
|
|
|
694
|
|
|
695 The Emacs parenthesis-matching feature shows you automatically how
|
|
|
696 parentheses match in the text. Whenever a self-inserting character that
|
|
|
697 is a closing delimiter is typed, the cursor moves momentarily to the
|
|
|
698 location of the matching opening delimiter, provided that is visible on
|
|
|
699 the screen. If it is not on the screen, some text starting with that
|
|
|
700 opening delimiter is displayed in the echo area. Either way, you see
|
|
|
701 the grouping you are closing off.
|
|
|
702
|
|
|
703 In Lisp, automatic matching applies only to parentheses. In C, it
|
|
|
704 also applies to braces and brackets. Emacs knows which characters to regard
|
|
|
705 as matching delimiters based on the syntax table set by the major
|
|
|
706 mode. @xref{Syntax}.
|
|
|
707
|
|
|
708 If the opening delimiter and closing delimiter are mismatched---as
|
|
|
709 in @samp{[x)}---the echo area displays a warning message. The
|
|
|
710 correct matches are specified in the syntax table.
|
|
|
711
|
|
|
712 @vindex blink-matching-paren
|
|
|
713 @vindex blink-matching-paren-distance
|
|
|
714 Two variables control parenthesis matching displays.
|
|
|
715 @code{blink-matching-paren} turns the feature on or off. The default is
|
|
|
716 @code{t} (match display is on); @code{nil} turns it off.
|
|
|
717 @code{blink-matching-paren-distance} specifies how many characters back
|
|
|
718 Emacs searches to find a matching opening delimiter. If the match is
|
|
|
719 not found in the specified region, scanning stops, and nothing is
|
|
|
720 displayed. This prevents wasting lots of time scanning when there is no
|
|
|
721 match. The default is 4000.
|
|
|
722
|
|
|
723 @node Comments, Balanced Editing, Matching, Programs
|
|
|
724 @section Manipulating Comments
|
|
|
725 @cindex comments
|
|
|
726 @kindex M-;
|
|
|
727 @cindex indentation
|
|
|
728 @findex indent-for-comment
|
|
|
729
|
|
|
730 The comment commands insert, kill and align comments.
|
|
|
731
|
|
|
732 @c WideCommands
|
|
|
733 @table @kbd
|
|
|
734 @item M-;
|
|
|
735 Insert or align comment (@code{indent-for-comment}).
|
|
|
736 @item C-x ;
|
|
|
737 Set comment column (@code{set-comment-column}).
|
|
|
738 @item C-u - C-x ;
|
|
|
739 Kill comment on current line (@code{kill-comment}).
|
|
|
740 @item M-@key{LFD}
|
|
|
741 Like @key{RET} followed by inserting and aligning a comment
|
|
|
742 (@code{indent-new-comment-line}).
|
|
|
743 @end table
|
|
|
744
|
|
|
745 The command that creates a comment is @kbd{Meta-;}
|
|
|
746 (@code{indent-for-comment}). If there is no comment already on the
|
|
|
747 line, a new comment is created and aligned at a specific column called
|
|
|
748 the @dfn{comment column}. Emacs creates the comment by inserting the
|
|
|
749 string at the value of @code{comment-start}; see below. Point is left
|
|
|
750 after that string. If the text of the line extends past the comment
|
|
|
751 column, indentation is done to a suitable boundary (usually, at least
|
|
|
752 one space is inserted). If the major mode has specified a string to
|
|
|
753 terminate comments, that string is inserted after point, to keep the
|
|
|
754 syntax valid.
|
|
|
755
|
|
|
756 You can also use @kbd{Meta-;} to align an existing comment. If a line
|
|
|
757 already contains the string that starts comments, @kbd{M-;} just moves
|
|
|
758 point after it and re-indents it to the conventional place. Exception:
|
|
|
759 comments starting in column 0 are not moved.
|
|
|
760
|
|
|
761 Some major modes have special rules for indenting certain kinds of
|
|
|
762 comments in certain contexts. For example, in Lisp code, comments which
|
|
|
763 start with two semicolons are indented as if they were lines of code,
|
|
|
764 instead of at the comment column. Comments which start with three
|
|
|
765 semicolons are supposed to start at the left margin. Emacs understands
|
|
|
766 these conventions by indenting a double-semicolon comment using @key{TAB}
|
|
|
767 and by not changing the indentation of a triple-semicolon comment at all.
|
|
|
768
|
|
|
769 @example
|
|
|
770 ;; This function is just an example.
|
|
|
771 ;;; Here either two or three semicolons are appropriate.
|
|
|
772 (defun foo (x)
|
|
|
773 ;;; And now, the first part of the function:
|
|
|
774 ;; The following line adds one.
|
|
|
775 (1+ x)) ; This line adds one.
|
|
|
776 @end example
|
|
|
777
|
|
|
778 In C code, a comment preceded on its line by nothing but whitespace
|
|
|
779 is indented like a line of code.
|
|
|
780
|
|
|
781 Even when an existing comment is properly aligned, @kbd{M-;} is still
|
|
|
782 useful for moving directly to the start of the comment.
|
|
|
783
|
|
|
784 @kindex C-u - C-x ;
|
|
|
785 @findex kill-comment
|
|
|
786 @kbd{C-u - C-x ;} (@code{kill-comment}) kills the comment on the
|
|
|
787 current line, if there is one. The indentation before the start of the
|
|
|
788 comment is killed as well. If there does not appear to be a comment in
|
|
|
789 the line, nothing happens. To reinsert the comment on another line,
|
|
|
790 move to the end of that line, type first @kbd{C-y}, and then @kbd{M-;}
|
|
|
791 to realign the comment. Note that @kbd{C-u - C-x ;} is not a distinct
|
|
|
792 key; it is @kbd{C-x ;} (@code{set-comment-column}) with a negative
|
|
|
793 argument. That command is programmed to call @code{kill-comment} when
|
|
|
794 called with a negative argument. However, @code{kill-comment} is a
|
|
|
795 valid command which you could bind directly to a key if you wanted to.
|
|
|
796
|
|
|
797 @subsection Multiple Lines of Comments
|
|
|
798
|
|
|
799 @kindex M-LFD
|
|
|
800 @cindex blank lines
|
|
|
801 @cindex Auto Fill mode
|
|
|
802 @findex indent-new-comment-line
|
|
|
803 If you are typing a comment and want to continue it on another line,
|
|
|
804 use the command @kbd{Meta-@key{LFD}} (@code{indent-new-comment-line}),
|
|
|
805 which terminates the comment you are typing, creates a new blank line
|
|
|
806 afterward, and begins a new comment indented under the old one. If
|
|
|
807 Auto Fill mode is on and you go past the fill column while typing, the
|
|
|
808 comment is continued in just this fashion. If point is
|
|
|
809 not at the end of the line when you type @kbd{M-@key{LFD}}, the text on
|
|
|
810 the rest of the line becomes part of the new comment line.
|
|
|
811
|
|
|
812 @subsection Options Controlling Comments
|
|
|
813
|
|
|
814 @vindex comment-column
|
|
|
815 @kindex C-x ;
|
|
|
816 @findex set-comment-column
|
|
|
817 The comment column is stored in the variable @code{comment-column}. You
|
|
|
818 can explicitly set it to a number. Alternatively, the command @kbd{C-x ;}
|
|
|
819 (@code{set-comment-column}) sets the comment column to the column point is
|
|
|
820 at. @kbd{C-u C-x ;} sets the comment column to match the last comment
|
|
|
821 before point in the buffer, and then calls @kbd{Meta-;} to align the
|
|
|
822 current line's comment under the previous one. Note that @kbd{C-u - C-x ;}
|
|
|
823 runs the function @code{kill-comment} as described above.
|
|
|
824
|
|
|
825 @code{comment-column} is a per-buffer variable; altering the variable
|
|
|
826 affects only the current buffer. You can also change the default value.
|
|
|
827 @xref{Locals}. Many major modes initialize this variable
|
|
|
828 for the current buffer.
|
|
|
829
|
|
|
830 @vindex comment-start-skip
|
|
|
831 The comment commands recognize comments based on the regular expression
|
|
|
832 that is the value of the variable @code{comment-start-skip}. This regexp
|
|
|
833 should not match the null string. It may match more than the comment
|
|
|
834 starting delimiter in the strictest sense of the word; for example, in C
|
|
|
835 mode the value of the variable is @code{@t{"/\\*+ *"}}, which matches extra
|
|
|
836 stars and spaces after the @samp{/*} itself. (Note that @samp{\\} is
|
|
|
837 needed in Lisp syntax to include a @samp{\} in the string, which is needed
|
|
|
838 to deny the first star its special meaning in regexp syntax. @xref{Regexps}.)
|
|
|
839
|
|
|
840 @vindex comment-start
|
|
|
841 @vindex comment-end
|
|
|
842 When a comment command makes a new comment, it inserts the value of
|
|
|
843 @code{comment-start} to begin it. The value of @code{comment-end} is
|
|
|
844 inserted after point and will follow the text you will insert
|
|
|
845 into the comment. In C mode, @code{comment-start} has the value
|
|
|
846 @w{@code{"/* "}} and @code{comment-end} has the value @w{@code{" */"}}.
|
|
|
847
|
|
|
848 @vindex comment-multi-line
|
|
|
849 @code{comment-multi-line} controls how @kbd{M-@key{LFD}}
|
|
|
850 (@code{indent-new-comment-line}) behaves when used inside a comment. If
|
|
|
851 @code{comment-multi-line} is @code{nil}, as it normally is, then
|
|
|
852 @kbd{M-@key{LFD}} terminates the comment on the starting line and starts
|
|
|
853 a new comment on the new following line. If @code{comment-multi-line}
|
|
|
854 is not @code{nil}, then @kbd{M-@key{LFD}} sets up the new following line
|
|
|
855 as part of the same comment that was found on the starting line. This
|
|
|
856 is done by not inserting a terminator on the old line and not inserting
|
|
|
857 a starter on the new line. In languages where multi-line comments are legal,
|
|
|
858 the value you choose for this variable is a matter of taste.
|
|
|
859
|
|
|
860 @vindex comment-indent-hook
|
|
|
861 The variable @code{comment-indent-hook} should contain a function that
|
|
|
862 is called to compute the indentation for a newly inserted comment or for
|
|
|
863 aligning an existing comment. Major modes set this variable differently.
|
|
|
864 The function is called with no arguments, but with point at the
|
|
|
865 beginning of the comment, or at the end of a line if a new comment is to
|
|
|
866 be inserted. The function should return the column in which the comment
|
|
|
867 ought to start. For example, in Lisp mode, the indent hook function
|
|
|
868 bases its decision on the number of semicolons that begin an existing
|
|
|
869 comment and on the code in the preceding lines.
|
|
|
870
|
|
|
871 @node Balanced Editing, Lisp Completion, Comments, Programs
|
|
|
872 @section Editing Without Unbalanced Parentheses
|
|
|
873
|
|
|
874 @table @kbd
|
|
|
875 @item M-(
|
|
|
876 Put parentheses around next sexp(s) (@code{insert-parentheses}).
|
|
|
877 @item M-)
|
|
|
878 Move past next close parenthesis and re-indent
|
|
|
879 (@code{move-over-close-and-reindent}).
|
|
|
880 @end table
|
|
|
881
|
|
|
882 @kindex M-(
|
|
|
883 @kindex M-)
|
|
|
884 @findex insert-parentheses
|
|
|
885 @findex move-over-close-and-reindent
|
|
|
886 The commands @kbd{M-(} (@code{insert-parentheses}) and @kbd{M-)}
|
|
|
887 (@code{move-over-close-and-reindent}) are designed to facilitate a style of
|
|
|
888 editing which keeps parentheses balanced at all times. @kbd{M-(} inserts a
|
|
|
889 pair of parentheses, either together as in @samp{()}, or, if given an
|
|
|
890 argument, around the next several sexps, and leaves point after the open
|
|
|
891 parenthesis. Instead of typing @kbd{( F O O )}, you can type @kbd{M-( F O
|
|
|
892 O}, which has the same effect except for leaving the cursor before the
|
|
|
893 close parenthesis. You can then type @kbd{M-)}, which moves past the
|
|
|
894 close parenthesis, deletes any indentation preceding it (in this example
|
|
|
895 there is none), and indents with @key{LFD} after it.
|
|
|
896
|
|
|
897 @node Lisp Completion, Documentation, Balanced Editing, Programs
|
|
|
898 @section Completion for Lisp Symbols
|
|
|
899 @cindex completion (symbol names)
|
|
|
900
|
|
|
901 Completion usually happens in the minibuffer. An exception is
|
|
|
902 completion for Lisp symbol names, which is available in all buffers.
|
|
|
903
|
|
|
904 @kindex M-TAB
|
|
|
905 @findex lisp-complete-symbol
|
|
|
906 The command @kbd{M-@key{TAB}} (@code{lisp-complete-symbol}) takes the
|
|
|
907 partial Lisp symbol before point to be an abbreviation, and compares it
|
|
|
908 against all non-trivial Lisp symbols currently known to Emacs. Any
|
|
|
909 additional characters that they all have in common are inserted at point.
|
|
|
910 Non-trivial symbols are those that have function definitions, values, or
|
|
|
911 properties.
|
|
|
912
|
|
|
913 If there is an open-parenthesis immediately before the beginning of
|
|
|
914 the partial symbol, only symbols with function definitions are considered
|
|
|
915 as completions.
|
|
|
916
|
|
|
917 If the partial name in the buffer has more than one possible completion
|
|
|
918 and they have no additional characters in common, a list of all possible
|
|
|
919 completions is displayed in another window.
|
|
|
920
|
|
|
921 @node Documentation, Change Log, Lisp Completion, Programs
|
|
|
922 @section Documentation Commands
|
|
|
923
|
|
|
924 @kindex C-h f
|
|
|
925 @findex describe-function
|
|
|
926 @kindex C-h v
|
|
|
927 @findex describe-variable
|
|
|
928 As you edit Lisp code to be run in Emacs, you can use the commands
|
|
|
929 @kbd{C-h f} (@code{describe-function}) and @kbd{C-h v}
|
|
|
930 (@code{describe-variable}) to print documentation of functions and
|
|
|
931 variables you want to call. These commands use the minibuffer to
|
|
|
932 read the name of a function or variable to document, and display the
|
|
|
933 documentation in a window.
|
|
|
934
|
|
|
935 For extra convenience, these commands provide default arguments based on
|
|
|
936 the code in the neighborhood of point. @kbd{C-h f} sets the default to the
|
|
|
937 function called in the innermost list containing point. @kbd{C-h v} uses
|
|
|
938 the symbol name around or adjacent to point as its default.
|
|
|
939
|
|
|
940 @findex manual-entry
|
|
|
941 The @kbd{M-x manual-entry} command gives you access to documentation
|
|
|
942 on Unix commands, system calls, and libraries. The command reads a
|
|
|
943 topic as an argument, and displays the Unix manual page for that topic.
|
|
|
944 @code{manual-entry} always searches all 8 sections of the
|
|
|
945 manual and concatenates all the entries it finds. For example,
|
|
|
946 the topic @samp{termcap} finds the description of the termcap library
|
|
|
947 from section 3, followed by the description of the termcap data base
|
|
|
948 from section 5.
|
|
|
949
|
|
|
950 @node Change Log, Tags, Documentation, Programs
|
|
|
951 @section Change Logs
|
|
|
952
|
|
|
953 @cindex change log
|
|
|
954 @findex add-change-log-entry
|
|
|
955 The Emacs command @kbd{M-x add-change-log-entry} helps you keep a record
|
|
|
956 of when and why you have changed a program. It assumes that you have a
|
|
|
957 file in which you write a chronological sequence of entries describing
|
|
|
958 individual changes. The default is to store the change entries in a file
|
|
|
959 called @file{ChangeLog} in the same directory as the file you are editing.
|
|
|
960 The same @file{ChangeLog} file therefore records changes for all the files
|
|
|
961 in a directory.
|
|
|
962
|
|
|
963 A change log entry starts with a header line that contains your name
|
|
|
964 and the current date. Except for these header lines, every line in the
|
|
|
965 change log starts with a tab. One entry can describe several changes;
|
|
|
966 each change starts with a line starting with a tab and a star. @kbd{M-x
|
|
|
967 add-change-log-entry} visits the change log file and creates a new entry
|
|
|
968 unless the most recent entry is for today's date and your name. In
|
|
|
969 either case, it adds a new line to start the description of another
|
|
|
970 change just after the header line of the entry. When @kbd{M-x
|
|
|
971 add-change-log-entry} is finished, all is prepared for you to edit in
|
|
|
972 the description of what you changed and how. You must then save the
|
|
|
973 change log file yourself.
|
|
|
974
|
|
|
975 The change log file is always visited in Indented Text mode, which means
|
|
|
976 that @key{LFD} and auto-filling indent each new line like the previous
|
|
|
977 line. This is convenient for entering the contents of an entry, which must
|
|
|
978 be indented. @xref{Text Mode}.
|
|
|
979
|
|
|
980 Here is an example of the formatting conventions used in the change log
|
|
|
981 for Emacs:
|
|
|
982
|
|
|
983 @smallexample
|
|
|
984 Wed Jun 26 19:29:32 1985 Richard M. Stallman (rms at mit-prep)
|
|
|
985
|
|
|
986 * xdisp.c (try_window_id):
|
|
|
987 If C-k is done at end of next-to-last line,
|
|
|
988 this fn updates window_end_vpos and cannot leave
|
|
|
989 window_end_pos nonnegative (it is zero, in fact).
|
|
|
990 If display is preempted before lines are output,
|
|
|
991 this is inconsistent. Fix by setting
|
|
|
992 blank_end_of_window to nonzero.
|
|
|
993
|
|
|
994 Tue Jun 25 05:25:33 1985 Richard M. Stallman (rms at mit-prep)
|
|
|
995
|
|
|
996 * cmds.c (Fnewline):
|
|
|
997 Call the auto fill hook if appropriate.
|
|
|
998
|
|
|
999 * xdisp.c (try_window_id):
|
|
|
1000 If point is found by compute_motion after xp, record that
|
|
|
1001 permanently. If display_text_line sets point position wrong
|
|
|
1002 (case where line is killed, point is at eob and that line is
|
|
|
1003 not displayed), set it again in final compute_motion.
|
|
|
1004 @end smallexample
|
|
|
1005
|
|
|
1006 @node Tags, Fortran, Change Log, Programs
|
|
|
1007 @section Tags Tables
|
|
|
1008 @cindex tags table
|
|
|
1009
|
|
|
1010 A @dfn{tags table} is a description of how a multi-file program is
|
|
|
1011 broken up into files. It lists the names of the component files and the
|
|
|
1012 names and positions of the functions (or other named subunits) in each
|
|
|
1013 file. Grouping the related files makes it possible to search or replace
|
|
|
1014 through all the files with one command. Recording the function names
|
|
|
1015 and positions makes possible the @kbd{M-.} command which finds the
|
|
|
1016 definition of a function by looking up which of the files it is in.
|
|
|
1017
|
|
|
1018 Tags tables are stored in files called @dfn{tags table files}. The
|
|
|
1019 conventional name for a tags table file is @file{TAGS}.
|
|
|
1020
|
|
|
1021 Each entry in the tags table records the name of one tag, the name of the
|
|
|
1022 file that the tag is defined in (implicitly), and the position in that file
|
|
|
1023 of the tag's definition.
|
|
|
1024
|
|
|
1025 Just what names from the described files are recorded in the tags table
|
|
|
1026 depends on the programming language of the described file. They
|
|
|
1027 normally include all functions and subroutines, and may also include
|
|
|
1028 global variables, data types, and anything else convenient. Each name
|
|
|
1029 recorded is called a @dfn{tag}.
|
|
|
1030
|
|
458
|
1031 @cindex C++ class browser, tags
|
|
|
1032 @cindex tags, C++
|
|
|
1033 @cindex class browser, C++
|
|
|
1034 @cindex Ebrowse
|
|
|
1035 The Ebrowse is a separate facility tailored for C++, with tags and a
|
|
704
|
1036 class browser. @xref{Ebrowse,,, ebrowse, Ebrowse User's Manual}.
|
|
458
|
1037
|
|
428
|
1038 @menu
|
|
|
1039 * Tag Syntax:: Tag syntax for various types of code and text files.
|
|
|
1040 * Create Tags Table:: Creating a tags table with @code{etags}.
|
|
|
1041 * Etags Regexps:: Create arbitrary tags using regular expressions.
|
|
|
1042 * Select Tags Table:: How to visit a tags table.
|
|
|
1043 * Find Tag:: Commands to find the definition of a specific tag.
|
|
|
1044 * Tags Search:: Using a tags table for searching and replacing.
|
|
|
1045 * List Tags:: Listing and finding tags defined in a file.
|
|
|
1046 @end menu
|
|
|
1047
|
|
458
|
1048 @node Tag Syntax
|
|
428
|
1049 @subsection Source File Tag Syntax
|
|
|
1050
|
|
|
1051 Here is how tag syntax is defined for the most popular languages:
|
|
|
1052
|
|
|
1053 @itemize @bullet
|
|
|
1054 @item
|
|
|
1055 In C code, any C function or typedef is a tag, and so are definitions of
|
|
|
1056 @code{struct}, @code{union} and @code{enum}. You can tag function
|
|
|
1057 declarations and external variables in addition to function definitions
|
|
|
1058 by giving the @samp{--declarations} option to @code{etags}.
|
|
|
1059 @code{#define} macro definitions and @code{enum} constants are also
|
|
|
1060 tags, unless you specify @samp{--no-defines} when making the tags table.
|
|
|
1061 Similarly, global variables are tags, unless you specify
|
|
|
1062 @samp{--no-globals}. Use of @samp{--no-globals} and @samp{--no-defines}
|
|
|
1063 can make the tags table file much smaller.
|
|
|
1064
|
|
|
1065 @item
|
|
|
1066 In C++ code, in addition to all the tag constructs of C code, member
|
|
|
1067 functions are also recognized, and optionally member variables if you
|
|
|
1068 use the @samp{--members} option. Tags for variables and functions in
|
|
|
1069 classes are named @samp{@var{class}::@var{variable}} and
|
|
|
1070 @samp{@var{class}::@var{function}}. @code{operator} functions tags are
|
|
|
1071 named, for example @samp{operator+}.
|
|
|
1072
|
|
|
1073 @item
|
|
|
1074 In Java code, tags include all the constructs recognized in C++, plus
|
|
|
1075 the @code{interface}, @code{extends} and @code{implements} constructs.
|
|
|
1076 Tags for variables and functions in classes are named
|
|
|
1077 @samp{@var{class}.@var{variable}} and @samp{@var{class}.@var{function}}.
|
|
|
1078
|
|
|
1079 @item
|
|
|
1080 In La@TeX{} text, the argument of any of the commands @code{\chapter},
|
|
|
1081 @code{\section}, @code{\subsection}, @code{\subsubsection},
|
|
|
1082 @code{\eqno}, @code{\label}, @code{\ref}, @code{\cite}, @code{\bibitem},
|
|
|
1083 @code{\part}, @code{\appendix}, @code{\entry}, or @code{\index}, is a
|
|
|
1084 tag.@refill
|
|
|
1085
|
|
|
1086 Other commands can make tags as well, if you specify them in the
|
|
460
|
1087 environment variable @code{TEXTAGS} before invoking @code{etags}. The
|
|
428
|
1088 value of this environment variable should be a colon-separated list of
|
|
|
1089 command names. For example,
|
|
|
1090
|
|
|
1091 @example
|
|
|
1092 TEXTAGS="def:newcommand:newenvironment"
|
|
|
1093 export TEXTAGS
|
|
|
1094 @end example
|
|
|
1095
|
|
|
1096 @noindent
|
|
|
1097 specifies (using Bourne shell syntax) that the commands @samp{\def},
|
|
|
1098 @samp{\newcommand} and @samp{\newenvironment} also define tags.
|
|
|
1099
|
|
|
1100 @item
|
|
|
1101 In Lisp code, any function defined with @code{defun}, any variable
|
|
|
1102 defined with @code{defvar} or @code{defconst}, and in general the first
|
|
|
1103 argument of any expression that starts with @samp{(def} in column zero, is
|
|
|
1104 a tag.
|
|
|
1105
|
|
|
1106 @item
|
|
|
1107 In Scheme code, tags include anything defined with @code{def} or with a
|
|
|
1108 construct whose name starts with @samp{def}. They also include variables
|
|
|
1109 set with @code{set!} at top level in the file.
|
|
|
1110 @end itemize
|
|
|
1111
|
|
|
1112 Several other languages are also supported:
|
|
|
1113
|
|
|
1114 @itemize @bullet
|
|
|
1115
|
|
|
1116 @item
|
|
|
1117 In Ada code, functions, procedures, packages, tasks, and types are
|
|
458
|
1118 tags. Use the @samp{--packages-only} option to create tags for
|
|
|
1119 packages only.
|
|
|
1120
|
|
|
1121 With Ada, it is possible to have the same name used for different
|
|
|
1122 entity kinds (e.g.@: the same name for a procedure and a function). Also,
|
|
|
1123 for things like packages, procedures and functions, there is the spec
|
|
|
1124 (i.e.@: the interface) and the body (i.e.@: the implementation). To
|
|
|
1125 facilitate the choice to the user, a tag value is appended with a
|
|
|
1126 qualifier:
|
|
|
1127
|
|
|
1128 @table @asis
|
|
|
1129 @item function
|
|
|
1130 @kbd{/f}
|
|
|
1131 @item procedure
|
|
|
1132 @kbd{/p}
|
|
|
1133 @item package spec
|
|
|
1134 @kbd{/s}
|
|
|
1135 @item package body
|
|
|
1136 @kbd{/b}
|
|
|
1137 @item type
|
|
|
1138 @kbd{/t}
|
|
|
1139 @item task
|
|
|
1140 @kbd{/k}
|
|
|
1141 @end table
|
|
|
1142
|
|
|
1143 So, as an example, @kbd{M-x find-tag bidule/b} will go directly to the
|
|
|
1144 body of the package @var{bidule} while @kbd{M-x find-tag bidule} will
|
|
|
1145 just search for any tag @var{bidule}.
|
|
428
|
1146
|
|
|
1147 @item
|
|
|
1148 In assembler code, labels appearing at the beginning of a line,
|
|
|
1149 followed by a colon, are tags.
|
|
|
1150
|
|
|
1151 @item
|
|
|
1152 In Bison or Yacc input files, each rule defines as a tag the nonterminal
|
|
|
1153 it constructs. The portions of the file that contain C code are parsed
|
|
|
1154 as C code.
|
|
|
1155
|
|
|
1156 @item
|
|
|
1157 In Cobol code, tags are paragraph names; that is, any word starting in
|
|
|
1158 column 8 and followed by a period.
|
|
|
1159
|
|
|
1160 @item
|
|
|
1161 In Erlang code, the tags are the functions, records, and macros defined
|
|
|
1162 in the file.
|
|
|
1163
|
|
|
1164 @item
|
|
|
1165 In Fortran code, functions, subroutines and blockdata are tags.
|
|
|
1166
|
|
|
1167 @item
|
|
458
|
1168 In makefiles, targets are tags.
|
|
|
1169
|
|
|
1170 @item
|
|
428
|
1171 In Objective C code, tags include Objective C definitions for classes,
|
|
|
1172 class categories, methods, and protocols.
|
|
|
1173
|
|
|
1174 @item
|
|
|
1175 In Pascal code, the tags are the functions and procedures defined in
|
|
|
1176 the file.
|
|
|
1177
|
|
|
1178 @item
|
|
|
1179 In Perl code, the tags are the procedures defined by the @code{sub},
|
|
|
1180 @code{my} and @code{local} keywords. Use @samp{--globals} if you want
|
|
|
1181 to tag global variables.
|
|
|
1182
|
|
|
1183 @item
|
|
709
|
1184 In PHP code, tags are functions, classes and defines. When using the
|
|
|
1185 @samp{--members} option, vars are tags too.
|
|
|
1186
|
|
|
1187 @item
|
|
458
|
1188 In PostScript code, the tags are the functions.
|
|
428
|
1189
|
|
|
1190 @item
|
|
709
|
1191 In Prolog code, tags are predicates and rules at the beginning of
|
|
|
1192 line.
|
|
428
|
1193
|
|
|
1194 @item
|
|
|
1195 In Python code, @code{def} or @code{class} at the beginning of a line
|
|
|
1196 generate a tag.
|
|
|
1197 @end itemize
|
|
|
1198
|
|
458
|
1199 You can also generate tags based on regexp matching (@pxref{Etags
|
|
|
1200 Regexps}) to handle other formats and languages.
|
|
428
|
1201
|
|
458
|
1202 @node Create Tags Table
|
|
428
|
1203 @subsection Creating Tags Tables
|
|
|
1204 @cindex @code{etags} program
|
|
|
1205
|
|
|
1206 The @code{etags} program is used to create a tags table file. It knows
|
|
|
1207 the syntax of several languages, as described in
|
|
|
1208 @iftex
|
|
|
1209 the previous section.
|
|
|
1210 @end iftex
|
|
|
1211 @ifinfo
|
|
|
1212 @ref{Tag Syntax}.
|
|
|
1213 @end ifinfo
|
|
|
1214 Here is how to run @code{etags}:
|
|
|
1215
|
|
|
1216 @example
|
|
|
1217 etags @var{inputfiles}@dots{}
|
|
|
1218 @end example
|
|
|
1219
|
|
|
1220 @noindent
|
|
|
1221 The @code{etags} program reads the specified files, and writes a tags
|
|
|
1222 table named @file{TAGS} in the current working directory. You can
|
|
|
1223 intermix compressed and plain text source file names. @code{etags}
|
|
|
1224 knows about the most common compression formats, and does the right
|
|
|
1225 thing. So you can compress all your source files and have @code{etags}
|
|
|
1226 look for compressed versions of its file name arguments, if it does not
|
|
|
1227 find uncompressed versions. Under MS-DOS, @code{etags} also looks for
|
|
|
1228 file names like @samp{mycode.cgz} if it is given @samp{mycode.c} on the
|
|
|
1229 command line and @samp{mycode.c} does not exist.
|
|
|
1230
|
|
|
1231 @code{etags} recognizes the language used in an input file based on
|
|
|
1232 its file name and contents. You can specify the language with the
|
|
|
1233 @samp{--language=@var{name}} option, described below.
|
|
|
1234
|
|
|
1235 If the tags table data become outdated due to changes in the files
|
|
|
1236 described in the table, the way to update the tags table is the same way it
|
|
|
1237 was made in the first place. It is not necessary to do this often.
|
|
|
1238
|
|
|
1239 If the tags table fails to record a tag, or records it for the wrong
|
|
|
1240 file, then Emacs cannot possibly find its definition. However, if the
|
|
|
1241 position recorded in the tags table becomes a little bit wrong (due to
|
|
|
1242 some editing in the file that the tag definition is in), the only
|
|
|
1243 consequence is a slight delay in finding the tag. Even if the stored
|
|
|
1244 position is very wrong, Emacs will still find the tag, but it must
|
|
|
1245 search the entire file for it.
|
|
|
1246
|
|
|
1247 So you should update a tags table when you define new tags that you want
|
|
|
1248 to have listed, or when you move tag definitions from one file to another,
|
|
|
1249 or when changes become substantial. Normally there is no need to update
|
|
|
1250 the tags table after each edit, or even every day.
|
|
|
1251
|
|
|
1252 One tags table can effectively include another. Specify the included
|
|
|
1253 tags file name with the @samp{--include=@var{file}} option when creating
|
|
|
1254 the file that is to include it. The latter file then acts as if it
|
|
|
1255 contained all the files specified in the included file, as well as the
|
|
|
1256 files it directly contains.
|
|
|
1257
|
|
|
1258 If you specify the source files with relative file names when you run
|
|
|
1259 @code{etags}, the tags file will contain file names relative to the
|
|
|
1260 directory where the tags file was initially written. This way, you can
|
|
|
1261 move an entire directory tree containing both the tags file and the
|
|
|
1262 source files, and the tags file will still refer correctly to the source
|
|
|
1263 files.
|
|
|
1264
|
|
|
1265 If you specify absolute file names as arguments to @code{etags}, then
|
|
|
1266 the tags file will contain absolute file names. This way, the tags file
|
|
|
1267 will still refer to the same files even if you move it, as long as the
|
|
|
1268 source files remain in the same place. Absolute file names start with
|
|
|
1269 @samp{/}, or with @samp{@var{device}:/} on MS-DOS and MS-Windows.
|
|
|
1270
|
|
|
1271 When you want to make a tags table from a great number of files, you
|
|
|
1272 may have problems listing them on the command line, because some systems
|
|
|
1273 have a limit on its length. The simplest way to circumvent this limit
|
|
|
1274 is to tell @code{etags} to read the file names from its standard input,
|
|
|
1275 by typing a dash in place of the file names, like this:
|
|
|
1276
|
|
|
1277 @smallexample
|
|
|
1278 find . -name "*.[chCH]" -print | etags -
|
|
|
1279 @end smallexample
|
|
|
1280
|
|
|
1281 Use the option @samp{--language=@var{name}} to specify the language
|
|
|
1282 explicitly. You can intermix these options with file names; each one
|
|
|
1283 applies to the file names that follow it. Specify
|
|
|
1284 @samp{--language=auto} to tell @code{etags} to resume guessing the
|
|
|
1285 language from the file names and file contents. Specify
|
|
|
1286 @samp{--language=none} to turn off language-specific processing
|
|
|
1287 entirely; then @code{etags} recognizes tags by regexp matching alone
|
|
|
1288 (@pxref{Etags Regexps}).
|
|
|
1289
|
|
|
1290 @samp{etags --help} prints the list of the languages @code{etags}
|
|
|
1291 knows, and the file name rules for guessing the language. It also prints
|
|
|
1292 a list of all the available @code{etags} options, together with a short
|
|
|
1293 explanation.
|
|
|
1294
|
|
458
|
1295 @node Etags Regexps
|
|
428
|
1296 @subsection Etags Regexps
|
|
|
1297
|
|
|
1298 The @samp{--regex} option provides a general way of recognizing tags
|
|
|
1299 based on regexp matching. You can freely intermix it with file names.
|
|
|
1300 Each @samp{--regex} option adds to the preceding ones, and applies only
|
|
|
1301 to the following files. The syntax is:
|
|
|
1302
|
|
|
1303 @smallexample
|
|
|
1304 --regex=/@var{tagregexp}[/@var{nameregexp}]/
|
|
|
1305 @end smallexample
|
|
|
1306
|
|
|
1307 @noindent
|
|
|
1308 where @var{tagregexp} is used to match the lines to tag. It is always
|
|
|
1309 anchored, that is, it behaves as if preceded by @samp{^}. If you want
|
|
|
1310 to account for indentation, just match any initial number of blanks by
|
|
|
1311 beginning your regular expression with @samp{[ \t]*}. In the regular
|
|
|
1312 expressions, @samp{\} quotes the next character, and @samp{\t} stands
|
|
|
1313 for the tab character. Note that @code{etags} does not handle the other
|
|
|
1314 C escape sequences for special characters.
|
|
|
1315
|
|
|
1316 @cindex interval operator (in regexps)
|
|
|
1317 The syntax of regular expressions in @code{etags} is the same as in
|
|
|
1318 Emacs, augmented with the @dfn{interval operator}, which works as in
|
|
|
1319 @code{grep} and @code{ed}. The syntax of an interval operator is
|
|
|
1320 @samp{\@{@var{m},@var{n}\@}}, and its meaning is to match the preceding
|
|
|
1321 expression at least @var{m} times and up to @var{n} times.
|
|
|
1322
|
|
|
1323 You should not match more characters with @var{tagregexp} than that
|
|
|
1324 needed to recognize what you want to tag. If the match is such that
|
|
|
1325 more characters than needed are unavoidably matched by @var{tagregexp}
|
|
|
1326 (as will usually be the case), you should add a @var{nameregexp}, to
|
|
|
1327 pick out just the tag. This will enable Emacs to find tags more
|
|
|
1328 accurately and to do completion on tag names more reliably. You can
|
|
|
1329 find some examples below.
|
|
|
1330
|
|
|
1331 The option @samp{--ignore-case-regex} (or @samp{-c}) is like
|
|
|
1332 @samp{--regex}, except that the regular expression provided will be
|
|
|
1333 matched without regard to case, which is appropriate for various
|
|
|
1334 programming languages.
|
|
|
1335
|
|
|
1336 The @samp{-R} option deletes all the regexps defined with
|
|
|
1337 @samp{--regex} options. It applies to the file names following it, as
|
|
|
1338 you can see from the following example:
|
|
|
1339
|
|
|
1340 @smallexample
|
|
|
1341 etags --regex=/@var{reg1}/ voo.doo --regex=/@var{reg2}/ \
|
|
|
1342 bar.ber -R --lang=lisp los.er
|
|
|
1343 @end smallexample
|
|
|
1344
|
|
|
1345 @noindent
|
|
|
1346 Here @code{etags} chooses the parsing language for @file{voo.doo} and
|
|
|
1347 @file{bar.ber} according to their contents. @code{etags} also uses
|
|
|
1348 @var{reg1} to recognize additional tags in @file{voo.doo}, and both
|
|
|
1349 @var{reg1} and @var{reg2} to recognize additional tags in
|
|
|
1350 @file{bar.ber}. @code{etags} uses the Lisp tags rules, and no regexp
|
|
|
1351 matching, to recognize tags in @file{los.er}.
|
|
|
1352
|
|
|
1353 A regular expression can be bound to a given language, by prepending
|
|
|
1354 it with @samp{@{lang@}}. When you do this, @code{etags} will use the
|
|
|
1355 regular expression only for files of that language. @samp{etags --help}
|
|
|
1356 prints the list of languages recognised by @code{etags}. The following
|
|
|
1357 example tags the @code{DEFVAR} macros in the Emacs source files.
|
|
|
1358 @code{etags} applies this regular expression to C files only:
|
|
|
1359
|
|
|
1360 @smallexample
|
|
|
1361 --regex='@{c@}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/'
|
|
|
1362 @end smallexample
|
|
|
1363
|
|
|
1364 @noindent
|
|
|
1365 This feature is particularly useful when storing a list of regular
|
|
|
1366 expressions in a file. The following option syntax instructs
|
|
|
1367 @code{etags} to read two files of regular expressions. The regular
|
|
|
1368 expressions contained in the second file are matched without regard to
|
|
|
1369 case.
|
|
|
1370
|
|
|
1371 @smallexample
|
|
|
1372 --regex=@@first-file --ignore-case-regex=@@second-file
|
|
|
1373 @end smallexample
|
|
|
1374
|
|
|
1375 @noindent
|
|
|
1376 A regex file contains one regular expressions per line. Empty lines,
|
|
|
1377 and lines beginning with space or tab are ignored. When the first
|
|
|
1378 character in a line is @samp{@@}, @code{etags} assumes that the rest of
|
|
|
1379 the line is the name of a file of regular expressions. This means that
|
|
|
1380 such files can be nested. All the other lines are taken to be regular
|
|
|
1381 expressions. For example, one can create a file called
|
|
|
1382 @samp{emacs.tags} with the following contents (the first line in the
|
|
|
1383 file is a comment):
|
|
|
1384
|
|
|
1385 @smallexample
|
|
|
1386 -- This is for GNU Emacs source files
|
|
|
1387 @{c@}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/\1/
|
|
|
1388 @end smallexample
|
|
|
1389
|
|
|
1390 @noindent
|
|
|
1391 and then use it like this:
|
|
|
1392
|
|
|
1393 @smallexample
|
|
|
1394 etags --regex=@@emacs.tags *.[ch] */*.[ch]
|
|
|
1395 @end smallexample
|
|
|
1396
|
|
|
1397 Here are some more examples. The regexps are quoted to protect them
|
|
|
1398 from shell interpretation.
|
|
|
1399
|
|
|
1400 @itemize @bullet
|
|
|
1401
|
|
|
1402 @item
|
|
|
1403 Tag Octave files:
|
|
|
1404
|
|
|
1405 @smallexample
|
|
|
1406 etags --language=none \
|
|
|
1407 --regex='/[ \t]*function.*=[ \t]*\([^ \t]*\)[ \t]*(/\1/' \
|
|
|
1408 --regex='/###key \(.*\)/\1/' \
|
|
|
1409 --regex='/[ \t]*global[ \t].*/' \
|
|
|
1410 *.m
|
|
|
1411 @end smallexample
|
|
|
1412
|
|
|
1413 @noindent
|
|
|
1414 Note that tags are not generated for scripts so that you have to add a
|
|
|
1415 line by yourself of the form `###key <script-name>' if you want to jump
|
|
|
1416 to it.
|
|
|
1417
|
|
|
1418 @item
|
|
|
1419 Tag Tcl files:
|
|
|
1420
|
|
|
1421 @smallexample
|
|
|
1422 etags --language=none --regex='/proc[ \t]+\([^ \t]+\)/\1/' *.tcl
|
|
|
1423 @end smallexample
|
|
|
1424
|
|
|
1425 @item
|
|
|
1426 Tag VHDL files:
|
|
|
1427
|
|
|
1428 @smallexample
|
|
|
1429 --language=none \
|
|
|
1430 --regex='/[ \t]*\(ARCHITECTURE\|CONFIGURATION\) +[^ ]* +OF/' \
|
|
|
1431 --regex='/[ \t]*\(ATTRIBUTE\|ENTITY\|FUNCTION\|PACKAGE\
|
|
|
1432 \( BODY\)?\|PROCEDURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/'
|
|
|
1433 @end smallexample
|
|
|
1434 @end itemize
|
|
|
1435
|
|
|
1436 @node Select Tags Table, Find Tag, Etags Regexps, Tags
|
|
|
1437 @subsection Selecting a Tags Table
|
|
|
1438
|
|
|
1439 @vindex tag-table-alist
|
|
|
1440 At any time Emacs has one @dfn{selected} tags table, and all the commands
|
|
|
1441 for working with tags tables use the selected one. To select a tags table,
|
|
|
1442 use the variable @code{tag-table-alist}.
|
|
|
1443
|
|
|
1444 The value of @code{tag-table-alist} is a list that determines which
|
|
|
1445 @code{TAGS} files should be active for a given buffer. This is not
|
|
|
1446 really an association list, in that all elements are checked. The car
|
|
|
1447 of each element of this list is a pattern against which the buffers file
|
|
|
1448 name is compared; if it matches, then the cdr of the list should be the
|
|
|
1449 name of the tags table to use. If more than one element of this list
|
|
|
1450 matches the buffers file name, all of the associated tags tables are
|
|
|
1451 used. Earlier ones are searched first.
|
|
|
1452
|
|
|
1453 If the car of elements of this list are strings, they are treated
|
|
|
1454 as regular-expressions against which the file is compared (like the
|
|
|
1455 @code{auto-mode-alist}). If they are not strings, they are evaluated.
|
|
|
1456 If they evaluate to non-@code{nil}, the current buffer is considered to
|
|
|
1457 match.
|
|
|
1458
|
|
|
1459 If the cdr of the elements of this list are strings, they are
|
|
|
1460 assumed to name a tags file. If they name a directory, the string
|
|
|
1461 @file{tags} is appended to them to get the file name. If they are not
|
|
|
1462 strings, they are evaluated and must return an appropriate string.
|
|
|
1463
|
|
|
1464 For example:
|
|
|
1465
|
|
|
1466 @example
|
|
|
1467 (setq tag-table-alist
|
|
440
|
1468 '(("/usr/src/public/perl/" . "/usr/src/public/perl/perl-3.0/")
|
|
|
1469 ("\\.el$" . "/usr/local/emacs/src/")
|
|
|
1470 ("/jbw/gnu/" . "/usr15/degree/stud/jbw/gnu/")
|
|
|
1471 ("" . "/usr/local/emacs/src/")
|
|
|
1472 ))
|
|
428
|
1473 @end example
|
|
|
1474
|
|
|
1475 The example defines the tags table alist in the following way:
|
|
|
1476
|
|
|
1477 @itemize @bullet
|
|
|
1478 @item
|
|
|
1479 Anything in the directory @file{/usr/src/public/perl/}
|
|
|
1480 should use the @file{TAGS} file @file{/usr/src/public/perl/perl-3.0/TAGS}.
|
|
|
1481 @item
|
|
|
1482 Files ending in @file{.el} should use the @file{TAGS} file
|
|
|
1483 @file{/usr/local/emacs/src/TAGS}.
|
|
|
1484 @item
|
|
|
1485 Anything in or below the directory @file{/jbw/gnu/} should use the
|
|
|
1486 @file{TAGS} file @file{/usr15/degree/stud/jbw/gnu/TAGS}.
|
|
|
1487 @end itemize
|
|
|
1488
|
|
|
1489 If you had a file called @file{/usr/jbw/foo.el}, it would use both
|
|
|
1490 @file{TAGS} files, @* @file{/usr/local/emacs/src/TAGS} and
|
|
|
1491 @file{/usr15/degree/stud/jbw/gnu/TAGS} (in that order), because it
|
|
|
1492 matches both patterns.
|
|
|
1493
|
|
|
1494 If the buffer-local variable @code{buffer-tag-table} is set, it names a
|
|
|
1495 tags table that is searched before all others when @code{find-tag} is
|
|
|
1496 executed from this buffer.
|
|
|
1497
|
|
|
1498 If there is a file called @file{TAGS} in the same directory as the file
|
|
|
1499 in question, then that tags file will always be used as well (after the
|
|
|
1500 @code{buffer-tag-table} but before the tables specified by this list).
|
|
|
1501
|
|
|
1502 If the variable @code{tags-file-name} is set, the @file{TAGS} file it names
|
|
|
1503 will apply to all buffers (for backwards compatibility.) It is searched
|
|
|
1504 first.
|
|
|
1505
|
|
|
1506 @vindex tags-always-build-completion-table
|
|
|
1507 If the value of the variable @code{tags-always-build-completion-table}
|
|
|
1508 is @code{t}, the tags file will always be added to the completion table
|
|
|
1509 without asking first, regardless of the size of the tags file.
|
|
|
1510
|
|
|
1511 @vindex tags-file-name
|
|
|
1512 @findex visit-tags-table
|
|
|
1513 The function @kbd{M-x visit-tags-table}, is largely made obsolete by
|
|
|
1514 the variable @code{tag-table-alist}, tells tags commands to use the tags
|
|
|
1515 table file @var{file} first. The @var{file} should be the name of a
|
|
|
1516 file created with the @code{etags} program. A directory name is also
|
|
|
1517 acceptable; it means the file @file{TAGS} in that directory. The
|
|
|
1518 function only stores the file name you provide in the variable
|
|
|
1519 @code{tags-file-name}. Emacs does not actually read in the tags table
|
|
|
1520 contents until you try to use them. You can set the variable explicitly
|
|
|
1521 instead of using @code{visit-tags-table}. The value of the variable
|
|
|
1522 @code{tags-file-name} is the name of the tags table used by all buffers.
|
|
|
1523 This is for backward compatibility, and is largely supplanted by the
|
|
|
1524 variable @code{tag-table-alist}.
|
|
|
1525
|
|
|
1526 @node Find Tag, Tags Search, Select Tags Table, Tags
|
|
|
1527 @subsection Finding a Tag
|
|
|
1528
|
|
|
1529 The most important thing that a tags table enables you to do is to find
|
|
|
1530 the definition of a specific tag.
|
|
|
1531
|
|
|
1532 @table @kbd
|
|
|
1533 @item M-.@: @var{tag &optional other-window}
|
|
|
1534 Find first definition of @var{tag} (@code{find-tag}).
|
|
|
1535 @item C-u M-.
|
|
|
1536 Find next alternate definition of last tag specified.
|
|
|
1537 @item C-x 4 . @var{tag}
|
|
|
1538 Find first definition of @var{tag}, but display it in another window
|
|
|
1539 (@code{find-tag-other-window}).
|
|
|
1540 @end table
|
|
|
1541
|
|
|
1542 @kindex M-.
|
|
|
1543 @findex find-tag
|
|
|
1544 @kbd{M-.}@: (@code{find-tag}) is the command to find the definition of
|
|
|
1545 a specified tag. It searches through the tags table for that tag, as a
|
|
|
1546 string, then uses the tags table information to determine the file in
|
|
|
1547 which the definition is used and the approximate character position of
|
|
|
1548 the definition in the file. Then @code{find-tag} visits the file,
|
|
|
1549 moves point to the approximate character position, and starts searching
|
|
|
1550 ever-increasing distances away for the text that should appear at
|
|
|
1551 the beginning of the definition.
|
|
|
1552
|
|
|
1553 If an empty argument is given (by typing @key{RET}), the sexp in the
|
|
|
1554 buffer before or around point is used as the name of the tag to find.
|
|
|
1555 @xref{Lists}, for information on sexps.
|
|
|
1556
|
|
|
1557 The argument to @code{find-tag} need not be the whole tag name; it can
|
|
|
1558 be a substring of a tag name. However, there can be many tag names
|
|
|
1559 containing the substring you specify. Since @code{find-tag} works by
|
|
|
1560 searching the text of the tags table, it finds the first tag in the table
|
|
|
1561 that the specified substring appears in. To find other tags that match
|
|
|
1562 the substring, give @code{find-tag} a numeric argument, as in @kbd{C-u
|
|
|
1563 M-.}. This does not read a tag name, but continues searching the tag
|
|
|
1564 table's text for another tag containing the same substring last used.
|
|
|
1565 If your keyboard has a real @key{META} key, @kbd{M-0 M-.}@: is an easier
|
|
|
1566 alternative to @kbd{C-u M-.}.
|
|
|
1567
|
|
|
1568 If the optional second argument @var{other-window} is non-@code{nil}, it uses
|
|
|
1569 another window to display the tag.
|
|
|
1570 Multiple active tags tables and completion are supported.
|
|
|
1571
|
|
|
1572 Variables of note include the following:
|
|
|
1573
|
|
|
1574 @vindex tag-table-alist
|
|
|
1575 @vindex tags-file-name
|
|
|
1576 @vindex tags-build-completion-table
|
|
|
1577 @vindex buffer-tag-table
|
|
|
1578 @vindex make-tags-files-invisible
|
|
|
1579 @vindex tag-mark-stack-max
|
|
|
1580
|
|
|
1581 @table @kbd
|
|
|
1582 @item tag-table-alist
|
|
|
1583 Controls which tables apply to which buffers.
|
|
440
|
1584 @item tags-file-name
|
|
428
|
1585 Stores a default tags table.
|
|
440
|
1586 @item tags-build-completion-table
|
|
428
|
1587 Controls completion behavior.
|
|
440
|
1588 @item buffer-tag-table
|
|
428
|
1589 Specifies a buffer-local table.
|
|
440
|
1590 @item make-tags-files-invisible
|
|
428
|
1591 Sets whether tags tables should be very hidden.
|
|
440
|
1592 @item tag-mark-stack-max
|
|
428
|
1593 Specifies how many tags-based hops to remember.
|
|
|
1594 @end table
|
|
|
1595
|
|
|
1596 @kindex C-x 4 .
|
|
|
1597 @findex find-tag-other-window
|
|
|
1598 Like most commands that can switch buffers, @code{find-tag} has another
|
|
|
1599 similar command that displays the new buffer in another window. @kbd{C-x 4
|
|
|
1600 .}@: invokes the function @code{find-tag-other-window}. (This key sequence
|
|
|
1601 ends with a period.)
|
|
|
1602
|
|
|
1603 Emacs comes with a tags table file @file{TAGS} (in the directory
|
|
|
1604 containing Lisp libraries) that includes all the Lisp libraries and all
|
|
|
1605 the C sources of Emacs. By specifying this file with @code{visit-tags-table}
|
|
|
1606 and then using @kbd{M-.}@: you can quickly look at the source of any Emacs
|
|
|
1607 function.
|
|
|
1608
|
|
|
1609 @node Tags Search, List Tags, Find Tag, Tags
|
|
|
1610 @subsection Searching and Replacing with Tags Tables
|
|
|
1611
|
|
|
1612 The commands in this section visit and search all the files listed in the
|
|
|
1613 selected tags table, one by one. For these commands, the tags table serves
|
|
|
1614 only to specify a sequence of files to search. A related command is
|
|
|
1615 @kbd{M-x grep} (@pxref{Compilation}).
|
|
|
1616
|
|
|
1617 @table @kbd
|
|
|
1618 @item M-x tags-search @key{RET} @var{regexp} @key{RET}
|
|
|
1619 Search for @var{regexp} through the files in the selected tags
|
|
|
1620 table.
|
|
|
1621 @item M-x tags-query-replace @key{RET} @var{regexp} @key{RET} @var{replacement} @key{RET}
|
|
|
1622 Perform a @code{query-replace-regexp} on each file in the selected tags table.
|
|
|
1623 @item M-,
|
|
|
1624 Restart one of the commands above, from the current location of point
|
|
|
1625 (@code{tags-loop-continue}).
|
|
|
1626 @end table
|
|
|
1627
|
|
|
1628 @findex tags-search
|
|
|
1629 @kbd{M-x tags-search} reads a regexp using the minibuffer, then
|
|
|
1630 searches for matches in all the files in the selected tags table, one
|
|
|
1631 file at a time. It displays the name of the file being searched so you
|
|
|
1632 can follow its progress. As soon as it finds an occurrence,
|
|
|
1633 @code{tags-search} returns.
|
|
|
1634
|
|
|
1635 @kindex M-,
|
|
|
1636 @findex tags-loop-continue
|
|
|
1637 Having found one match, you probably want to find all the rest. To find
|
|
|
1638 one more match, type @kbd{M-,} (@code{tags-loop-continue}) to resume the
|
|
|
1639 @code{tags-search}. This searches the rest of the current buffer, followed
|
|
|
1640 by the remaining files of the tags table.@refill
|
|
|
1641
|
|
|
1642 @findex tags-query-replace
|
|
|
1643 @kbd{M-x tags-query-replace} performs a single
|
|
|
1644 @code{query-replace-regexp} through all the files in the tags table. It
|
|
|
1645 reads a regexp to search for and a string to replace with, just like
|
|
|
1646 ordinary @kbd{M-x query-replace-regexp}. It searches much like @kbd{M-x
|
|
|
1647 tags-search}, but repeatedly, processing matches according to your
|
|
|
1648 input. @xref{Replace}, for more information on query replace.
|
|
|
1649
|
|
|
1650 It is possible to get through all the files in the tags table with a
|
|
|
1651 single invocation of @kbd{M-x tags-query-replace}. But often it is
|
|
|
1652 useful to exit temporarily, which you can do with any input event that
|
|
|
1653 has no special query replace meaning. You can resume the query replace
|
|
|
1654 subsequently by typing @kbd{M-,}; this command resumes the last tags
|
|
|
1655 search or replace command that you did.
|
|
|
1656
|
|
|
1657 The commands in this section carry out much broader searches than the
|
|
|
1658 @code{find-tag} family. The @code{find-tag} commands search only for
|
|
|
1659 definitions of tags that match your substring or regexp. The commands
|
|
|
1660 @code{tags-search} and @code{tags-query-replace} find every occurrence
|
|
|
1661 of the regexp, as ordinary search commands and replace commands do in
|
|
|
1662 the current buffer.
|
|
|
1663
|
|
|
1664 These commands create buffers only temporarily for the files that they
|
|
|
1665 have to search (those which are not already visited in Emacs buffers).
|
|
|
1666 Buffers in which no match is found are quickly killed; the others
|
|
|
1667 continue to exist.
|
|
|
1668
|
|
|
1669 It may have struck you that @code{tags-search} is a lot like
|
|
|
1670 @code{grep}. You can also run @code{grep} itself as an inferior of
|
|
|
1671 Emacs and have Emacs show you the matching lines one by one. This works
|
|
|
1672 much like running a compilation; finding the source locations of the
|
|
|
1673 @code{grep} matches works like finding the compilation errors.
|
|
|
1674 @xref{Compilation}.
|
|
|
1675
|
|
|
1676 If you wish to process all the files in a selected tags table, but
|
|
|
1677 @kbd{M-x tags-search} and @kbd{M-x tags-query-replace} are not giving
|
|
|
1678 you the desired result, you can use @kbd{M-x next-file}.
|
|
|
1679
|
|
|
1680 @table @kbd
|
|
|
1681 @item C-u M-x next-file
|
|
|
1682 With a numeric argument, regardless of its value, visit the first
|
|
|
1683 file in the tags table and prepare to advance sequentially by files.
|
|
|
1684 @item M-x next-file
|
|
|
1685 Visit the next file in the selected tags table.
|
|
|
1686 @end table
|
|
|
1687
|
|
|
1688 @node List Tags, , Tags Search, Tags
|
|
|
1689 @subsection Tags Table Inquiries
|
|
|
1690
|
|
|
1691 @table @kbd
|
|
|
1692 @item M-x list-tags
|
|
|
1693 Display a list of the tags defined in a specific program file.
|
|
|
1694 @item M-x tags-apropos
|
|
|
1695 Display a list of all tags matching a specified regexp.
|
|
|
1696 @end table
|
|
|
1697
|
|
|
1698 @findex list-tags
|
|
|
1699 @kbd{M-x list-tags} reads the name of one of the files described by the
|
|
|
1700 selected tags table, and displays a list of all the tags defined in that
|
|
|
1701 file. The ``file name'' argument is really just a string to compare
|
|
|
1702 against the names recorded in the tags table; it is read as a string rather
|
|
|
1703 than a file name. Therefore, completion and defaulting are not
|
|
|
1704 available, and you must enter the string the same way it appears in the tag
|
|
|
1705 table. Do not include a directory as part of the file name unless the file
|
|
|
1706 name recorded in the tags table contains that directory.
|
|
|
1707
|
|
|
1708 @findex tags-apropos
|
|
|
1709 @kbd{M-x tags-apropos} is like @code{apropos} for tags. It reads a regexp,
|
|
|
1710 then finds all the tags in the selected tags table whose entries match that
|
|
|
1711 regexp, and displays the tag names found.
|
|
|
1712
|
|
|
1713 @node Fortran, Asm Mode, Tags, Programs
|
|
|
1714 @section Fortran Mode
|
|
|
1715 @cindex Fortran mode
|
|
|
1716
|
|
|
1717 Fortran mode provides special motion commands for Fortran statements and
|
|
|
1718 subprograms, and indentation commands that understand Fortran conventions
|
|
|
1719 of nesting, line numbers, and continuation statements.
|
|
|
1720
|
|
|
1721 Special commands for comments are provided because Fortran comments are
|
|
|
1722 unlike those of other languages.
|
|
|
1723
|
|
|
1724 Built-in abbrevs optionally save typing when you insert Fortran keywords.
|
|
|
1725
|
|
|
1726 @findex fortran-mode
|
|
|
1727 Use @kbd{M-x fortran-mode} to switch to this major mode. Doing so calls
|
|
|
1728 the value of @code{fortran-mode-hook} as a function of no arguments if
|
|
|
1729 that variable has a non-@code{nil} value.
|
|
|
1730
|
|
|
1731 @menu
|
|
|
1732 * Motion: Fortran Motion. Moving point by statements or subprograms.
|
|
|
1733 * Indent: Fortran Indent. Indentation commands for Fortran.
|
|
|
1734 * Comments: Fortran Comments. Inserting and aligning comments.
|
|
|
1735 * Columns: Fortran Columns. Measuring columns for valid Fortran.
|
|
|
1736 * Abbrev: Fortran Abbrev. Built-in abbrevs for Fortran keywords.
|
|
|
1737 @end menu
|
|
|
1738
|
|
|
1739 Fortran mode was contributed by Michael Prange.
|
|
|
1740
|
|
|
1741 @node Fortran Motion, Fortran Indent, Fortran, Fortran
|
|
|
1742 @subsection Motion Commands
|
|
|
1743
|
|
|
1744 Fortran mode provides special commands to move by subprograms (functions
|
|
|
1745 and subroutines) and by statements. There is also a command to put the
|
|
|
1746 region around one subprogram, which is convenient for killing it or moving it.
|
|
|
1747
|
|
|
1748 @kindex C-M-a (Fortran mode)
|
|
|
1749 @kindex C-M-e (Fortran mode)
|
|
|
1750 @kindex C-M-h (Fortran mode)
|
|
|
1751 @kindex C-c C-p (Fortran mode)
|
|
|
1752 @kindex C-c C-n (Fortran mode)
|
|
|
1753 @findex beginning-of-fortran-subprogram
|
|
|
1754 @findex end-of-fortran-subprogram
|
|
|
1755 @findex mark-fortran-subprogram
|
|
|
1756 @findex fortran-previous-statement
|
|
|
1757 @findex fortran-next-statement
|
|
|
1758
|
|
|
1759 @table @kbd
|
|
|
1760 @item C-M-a
|
|
|
1761 Move to beginning of subprogram@*
|
|
|
1762 (@code{beginning-of-fortran-subprogram}).
|
|
|
1763 @item C-M-e
|
|
|
1764 Move to end of subprogram (@code{end-of-fortran-subprogram}).
|
|
|
1765 @item C-M-h
|
|
|
1766 Put point at beginning of subprogram and mark at end
|
|
|
1767 (@code{mark-fortran-subprogram}).
|
|
|
1768 @item C-c C-n
|
|
|
1769 Move to beginning of current or next statement
|
|
|
1770 (@code{fortran-next-@*statement}).
|
|
|
1771 @item C-c C-p
|
|
|
1772 Move to beginning of current or previous statement
|
|
|
1773 (@code{fortran-@*previous-statement}).
|
|
|
1774 @end table
|
|
|
1775
|
|
|
1776 @node Fortran Indent, Fortran Comments, Fortran Motion, Fortran
|
|
|
1777 @subsection Fortran Indentation
|
|
|
1778
|
|
|
1779 Special commands and features are available for indenting Fortran
|
|
|
1780 code. They make sure various syntactic entities (line numbers, comment line
|
|
|
1781 indicators, and continuation line flags) appear in the columns that are
|
|
|
1782 required for standard Fortran.
|
|
|
1783
|
|
|
1784 @menu
|
|
|
1785 * Commands: ForIndent Commands. Commands for indenting Fortran.
|
|
|
1786 * Numbers: ForIndent Num. How line numbers auto-indent.
|
|
|
1787 * Conv: ForIndent Conv. Conventions you must obey to avoid trouble.
|
|
|
1788 * Vars: ForIndent Vars. Variables controlling Fortran indent style.
|
|
|
1789 @end menu
|
|
|
1790
|
|
|
1791 @node ForIndent Commands, ForIndent Num, Fortran Indent, Fortran Indent
|
|
|
1792 @subsubsection Fortran Indentation Commands
|
|
|
1793
|
|
|
1794 @table @kbd
|
|
|
1795 @item @key{TAB}
|
|
|
1796 Indent the current line (@code{fortran-indent-line}).
|
|
|
1797 @item M-@key{LFD}
|
|
|
1798 Break the current line and set up a continuation line.
|
|
|
1799 @item C-M-q
|
|
|
1800 Indent all the lines of the subprogram point is in
|
|
|
1801 (@code{fortran-indent-subprogram}).
|
|
|
1802 @end table
|
|
|
1803
|
|
|
1804 @findex fortran-indent-line
|
|
|
1805 @key{TAB} is redefined by Fortran mode to reindent the current line for
|
|
|
1806 Fortran (@code{fortran-indent-line}). Line numbers and continuation
|
|
|
1807 markers are indented to their required columns, and the body of the
|
|
|
1808 statement is independently indented, based on its nesting in the program.
|
|
|
1809
|
|
|
1810 @kindex C-M-q (Fortran mode)
|
|
|
1811 @findex fortran-indent-subprogram
|
|
|
1812 The key @kbd{C-M-q} is redefined as @code{fortran-indent-subprogram}, a
|
|
|
1813 command that reindents all the lines of the Fortran subprogram (function or
|
|
|
1814 subroutine) containing point.
|
|
|
1815
|
|
|
1816 @kindex M-LFD (Fortran mode)
|
|
|
1817 @findex fortran-split-line
|
|
|
1818 The key @kbd{M-@key{LFD}} is redefined as @code{fortran-split-line}, a
|
|
|
1819 command to split a line in the appropriate fashion for Fortran. In a
|
|
|
1820 non-comment line, the second half becomes a continuation line and is
|
|
|
1821 indented accordingly. In a comment line, both halves become separate
|
|
|
1822 comment lines.
|
|
|
1823
|
|
|
1824 @node ForIndent Num, ForIndent Conv, ForIndent Commands, Fortran Indent
|
|
|
1825 @subsubsection Line Numbers and Continuation
|
|
|
1826
|
|
|
1827 If a number is the first non-whitespace in the line, it is assumed to be
|
|
|
1828 a line number and is moved to columns 0 through 4. (Columns are always
|
|
|
1829 counted from 0 in XEmacs.) If the text on the line starts with the
|
|
|
1830 conventional Fortran continuation marker @samp{$}, it is moved to column 5.
|
|
|
1831 If the text begins with any non whitespace character in column 5, it is
|
|
|
1832 assumed to be an unconventional continuation marker and remains in column
|
|
|
1833 5.
|
|
|
1834
|
|
|
1835 @vindex fortran-line-number-indent
|
|
|
1836 Line numbers of four digits or less are normally indented one space.
|
|
|
1837 This amount is controlled by the variable @code{fortran-line-number-indent},
|
|
|
1838 which is the maximum indentation a line number can have. Line numbers
|
|
|
1839 are indented to right-justify them to end in column 4 unless that would
|
|
|
1840 require more than the maximum indentation. The default value of the
|
|
|
1841 variable is 1.
|
|
|
1842
|
|
|
1843 @vindex fortran-electric-line-number
|
|
|
1844 Simply inserting a line number is enough to indent it according to these
|
|
|
1845 rules. As each digit is inserted, the indentation is recomputed. To turn
|
|
|
1846 off this feature, set the variable @code{fortran-electric-line-number} to
|
|
|
1847 @code{nil}. Then inserting line numbers is like inserting anything else.
|
|
|
1848
|
|
|
1849 @node ForIndent Conv, ForIndent Vars, ForIndent Num, Fortran Indent
|
|
|
1850 @subsubsection Syntactic Conventions
|
|
|
1851
|
|
|
1852 Fortran mode assumes that you follow certain conventions that simplify
|
|
|
1853 the task of understanding a Fortran program well enough to indent it
|
|
|
1854 properly:
|
|
|
1855
|
|
|
1856 @vindex fortran-continuation-char
|
|
|
1857 @itemize @bullet
|
|
|
1858 @item
|
|
|
1859 Two nested @samp{do} loops never share a @samp{continue} statement.
|
|
|
1860
|
|
|
1861 @item
|
|
|
1862 The same character appears in column 5 of all continuation lines. It
|
|
|
1863 is the value of the variable @code{fortran-continuation-char}.
|
|
|
1864 By default, this character is @samp{$}.
|
|
|
1865 @end itemize
|
|
|
1866
|
|
|
1867 @noindent
|
|
|
1868 If you fail to follow these conventions, the indentation commands may
|
|
|
1869 indent some lines unaesthetically. However, a correct Fortran program will
|
|
|
1870 retain its meaning when reindented even if the conventions are not
|
|
|
1871 followed.
|
|
|
1872
|
|
|
1873 @node ForIndent Vars, , ForIndent Conv, Fortran Indent
|
|
|
1874 @subsubsection Variables for Fortran Indentation
|
|
|
1875
|
|
|
1876 @vindex fortran-do-indent
|
|
|
1877 @vindex fortran-if-indent
|
|
|
1878 @vindex fortran-continuation-indent
|
|
|
1879 @vindex fortran-check-all-num-for-matching-do
|
|
|
1880 @vindex fortran-minimum-statement-indent
|
|
|
1881 Several additional variables control how Fortran indentation works.
|
|
|
1882
|
|
|
1883 @table @code
|
|
|
1884 @item fortran-do-indent
|
|
|
1885 Extra indentation within each level of @samp{do} statement (the default is 3).
|
|
|
1886
|
|
|
1887 @item fortran-if-indent
|
|
|
1888 Extra indentation within each level of @samp{if} statement (the default is 3).
|
|
|
1889
|
|
|
1890 @item fortran-continuation-indent
|
|
|
1891 Extra indentation for bodies of continuation lines (the default is 5).
|
|
|
1892
|
|
|
1893 @item fortran-check-all-num-for-matching-do
|
|
|
1894 If this is @code{nil}, indentation assumes that each @samp{do}
|
|
|
1895 statement ends on a @samp{continue} statement. Therefore, when
|
|
|
1896 computing indentation for a statement other than @samp{continue}, it
|
|
|
1897 can save time by not checking for a @samp{do} statement ending there.
|
|
|
1898 If this is non-@code{nil}, indenting any numbered statement must check
|
|
|
1899 for a @samp{do} that ends there. The default is @code{nil}.
|
|
|
1900
|
|
|
1901 @item fortran-minimum-statement-indent
|
|
|
1902 Minimum indentation for Fortran statements. For standard Fortran,
|
|
|
1903 this is 6. Statement bodies are always indented at least this much.
|
|
|
1904 @end table
|
|
|
1905
|
|
|
1906 @node Fortran Comments, Fortran Columns, Fortran Indent, Fortran
|
|
|
1907 @subsection Comments
|
|
|
1908
|
|
|
1909 The usual Emacs comment commands assume that a comment can follow a line
|
|
|
1910 of code. In Fortran, the standard comment syntax requires an entire line
|
|
|
1911 to be just a comment. Therefore, Fortran mode replaces the standard Emacs
|
|
|
1912 comment commands and defines some new variables.
|
|
|
1913
|
|
|
1914 Fortran mode can also handle a non-standard comment syntax where comments
|
|
|
1915 start with @samp{!} and can follow other text. Because only some Fortran
|
|
|
1916 compilers accept this syntax, Fortran mode will not insert such comments
|
|
|
1917 unless you have specified to do so in advance by setting the variable
|
|
|
1918 @code{comment-start} to @samp{"!"} (@pxref{Variables}).
|
|
|
1919
|
|
|
1920 @table @kbd
|
|
|
1921 @item M-;
|
|
|
1922 Align comment or insert new comment (@code{fortran-comment-indent}).
|
|
|
1923
|
|
|
1924 @item C-x ;
|
|
|
1925 Applies to nonstandard @samp{!} comments only.
|
|
|
1926
|
|
|
1927 @item C-c ;
|
|
|
1928 Turn all lines of the region into comments, or (with arg)
|
|
|
1929 turn them back into real code (@code{fortran-comment-region}).
|
|
|
1930 @end table
|
|
|
1931
|
|
|
1932 @kbd{M-;} in Fortran mode is redefined as the command
|
|
|
1933 @code{fortran-comment-indent}. Like the usual @kbd{M-;} command,
|
|
|
1934 it recognizes an existing comment and aligns its text appropriately.
|
|
|
1935 If there is no existing comment, a comment is inserted and aligned.
|
|
|
1936
|
|
|
1937 Inserting and aligning comments is not the same in Fortran mode as in
|
|
|
1938 other modes. When a new comment must be inserted, a full-line comment is
|
|
|
1939 inserted if the current line is blank. On a non-blank line, a
|
|
|
1940 non-standard @samp{!} comment is inserted if you previously specified
|
|
|
1941 you wanted to use them. Otherwise a full-line comment is inserted on a
|
|
|
1942 new line before the current line.
|
|
|
1943
|
|
|
1944 Non-standard @samp{!} comments are aligned like comments in other
|
|
|
1945 languages, but full-line comments are aligned differently. In a
|
|
|
1946 standard full-line comment, the comment delimiter itself must always
|
|
|
1947 appear in column zero. What can be aligned is the text within the
|
|
|
1948 comment. You can choose from three styles of alignment by setting the
|
|
|
1949 variable @code{fortran-comment-indent-style} to one of these values:
|
|
|
1950
|
|
|
1951 @vindex fortran-comment-indent-style
|
|
|
1952 @vindex fortran-comment-line-column
|
|
|
1953 @table @code
|
|
|
1954 @item fixed
|
|
|
1955 The text is aligned at a fixed column, which is the value of
|
|
|
1956 @code{fortran-comment-line-column}. This is the default.
|
|
|
1957 @item relative
|
|
|
1958 The text is aligned as if it were a line of code, but with an
|
|
|
1959 additional @code{fortran-comment-line-column} columns of indentation.
|
|
|
1960 @item nil
|
|
|
1961 Text in full-line columns is not moved automatically.
|
|
|
1962 @end table
|
|
|
1963
|
|
|
1964 @vindex fortran-comment-indent-char
|
|
|
1965 You can also specify the character to be used to indent within
|
|
|
1966 full-line comments by setting the variable @code{fortran-comment-indent-char}
|
|
|
1967 to the character you want to use.
|
|
|
1968
|
|
|
1969 @vindex comment-line-start
|
|
|
1970 @vindex comment-line-start-skip
|
|
|
1971 Fortran mode introduces two variables @code{comment-line-start} and
|
|
|
1972 @code{comment-line-start-skip}, which do for full-line comments what
|
|
|
1973 @code{comment-start} and @code{comment-start-skip} do for
|
|
|
1974 ordinary text-following comments. Normally these are set properly by
|
|
|
1975 Fortran mode, so you do not need to change them.
|
|
|
1976
|
|
|
1977 The normal Emacs comment command @kbd{C-x ;} has not been redefined.
|
|
|
1978 It can therefore be used if you use @samp{!} comments, but is useless in
|
|
|
1979 Fortran mode otherwise.
|
|
|
1980
|
|
|
1981 @kindex C-c ; (Fortran mode)
|
|
|
1982 @findex fortran-comment-region
|
|
|
1983 @vindex fortran-comment-region
|
|
|
1984 The command @kbd{C-c ;} (@code{fortran-comment-region}) turns all the
|
|
|
1985 lines of the region into comments by inserting the string @samp{C$$$} at
|
|
|
1986 the front of each one. With a numeric arg, the region is turned back into
|
|
|
1987 live code by deleting @samp{C$$$} from the front of each line. You can
|
|
|
1988 control the string used for the comments by setting the variable
|
|
|
1989 @code{fortran-comment-region}. Note that here we have an example of a
|
|
|
1990 command and a variable with the same name; the two uses of the name never
|
|
|
1991 conflict because in Lisp and in Emacs it is always clear from the context
|
|
|
1992 which one is referred to.
|
|
|
1993
|
|
|
1994 @node Fortran Columns, Fortran Abbrev, Fortran Comments, Fortran
|
|
|
1995 @subsection Columns
|
|
|
1996
|
|
|
1997 @table @kbd
|
|
|
1998 @item C-c C-r
|
|
|
1999 Displays a ``column ruler'' momentarily above the current line
|
|
|
2000 (@code{fortran-column-ruler}).
|
|
|
2001 @item C-c C-w
|
|
|
2002 Splits the current window horizontally so that it is 72 columns wide.
|
|
|
2003 This may help you avoid going over that limit (@code{fortran-window-create}).
|
|
|
2004 @end table
|
|
|
2005
|
|
|
2006 @kindex C-c C-r (Fortran mode)
|
|
|
2007 @findex fortran-column-ruler
|
|
|
2008 The command @kbd{C-c C-r} (@code{fortran-column-ruler}) shows a column
|
|
|
2009 ruler above the current line. The comment ruler consists of two lines
|
|
|
2010 of text that show you the locations of columns with special significance
|
|
|
2011 in Fortran programs. Square brackets show the limits of the columns for
|
|
|
2012 line numbers, and curly brackets show the limits of the columns for the
|
|
|
2013 statement body. Column numbers appear above them.
|
|
|
2014
|
|
|
2015 Note that the column numbers count from zero, as always in XEmacs. As
|
|
|
2016 a result, the numbers may not be those you are familiar with; but the
|
|
|
2017 actual positions in the line are standard Fortran.
|
|
|
2018
|
|
|
2019 The text used to display the column ruler is the value of the variable
|
|
|
2020 @code{fortran-comment-ruler}. By changing this variable, you can change
|
|
|
2021 the display.
|
|
|
2022
|
|
|
2023 @kindex C-c C-w (Fortran mode)
|
|
|
2024 @findex fortran-window-create
|
|
|
2025 For even more help, use @kbd{C-c C-w} (@code{fortran-window-create}), a
|
|
|
2026 command which splits the current window horizontally, resulting in a window 72
|
|
|
2027 columns wide. When you edit in this window, you can immediately see
|
|
|
2028 when a line gets too wide to be correct Fortran.
|
|
|
2029
|
|
|
2030 @node Fortran Abbrev, , Fortran Columns, Fortran
|
|
|
2031 @subsection Fortran Keyword Abbrevs
|
|
|
2032
|
|
|
2033 Fortran mode provides many built-in abbrevs for common keywords and
|
|
|
2034 declarations. These are the same sort of abbrevs that you can define
|
|
|
2035 yourself. To use them, you must turn on Abbrev mode. @pxref{Abbrevs}.
|
|
|
2036
|
|
|
2037 The built-in abbrevs are unusual in one way: they all start with a
|
|
|
2038 semicolon. You cannot normally use semicolon in an abbrev, but Fortran
|
|
|
2039 mode makes this possible by changing the syntax of semicolon to ``word
|
|
|
2040 constituent''.
|
|
|
2041
|
|
|
2042 For example, one built-in Fortran abbrev is @samp{;c} for
|
|
|
2043 @samp{continue}. If you insert @samp{;c} and then insert a punctuation
|
|
|
2044 character such as a space or a newline, the @samp{;c} changes
|
|
|
2045 automatically to @samp{continue}, provided Abbrev mode is enabled.@refill
|
|
|
2046
|
|
|
2047 Type @samp{;?} or @samp{;C-h} to display a list of all built-in
|
|
|
2048 Fortran abbrevs and what they stand for.
|
|
|
2049
|
|
|
2050 @node Asm Mode, , Fortran, Programs
|
|
|
2051 @section Asm Mode
|
|
|
2052
|
|
|
2053 @cindex Asm mode
|
|
|
2054 Asm mode is a major mode for editing files of assembler code. It
|
|
|
2055 defines these commands:
|
|
|
2056
|
|
|
2057 @table @kbd
|
|
|
2058 @item @key{TAB}
|
|
|
2059 @code{tab-to-tab-stop}.
|
|
|
2060 @item @key{LFD}
|
|
|
2061 Insert a newline and then indent using @code{tab-to-tab-stop}.
|
|
|
2062 @item :
|
|
|
2063 Insert a colon and then remove the indentation from before the label
|
|
|
2064 preceding colon. Then do @code{tab-to-tab-stop}.
|
|
|
2065 @item ;
|
|
|
2066 Insert or align a comment.
|
|
|
2067 @end table
|
|
|
2068
|
|
|
2069 The variable @code{asm-comment-char} specifies which character
|
|
|
2070 starts comments in assembler syntax.
|
