1 |
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2 | =for comment
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3 | This document is in Pod format. To read this, use a Pod formatter,
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4 | like "perldoc perlpod".
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5 |
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6 | =head1 NAME
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7 | X<POD> X<plain old documentation>
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8 |
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9 | perlpod - the Plain Old Documentation format
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10 |
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11 | =head1 DESCRIPTION
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12 |
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13 | Pod is a simple-to-use markup language used for writing documentation
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14 | for Perl, Perl programs, and Perl modules.
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15 |
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16 | Translators are available for converting Pod to various formats
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17 | like plain text, HTML, man pages, and more.
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18 |
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19 | Pod markup consists of three basic kinds of paragraphs:
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20 | L<ordinary|/"Ordinary Paragraph">,
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21 | L<verbatim|/"Verbatim Paragraph">, and
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22 | L<command|/"Command Paragraph">.
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23 |
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24 |
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25 | =head2 Ordinary Paragraph
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26 | X<POD, ordinary paragraph>
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27 |
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28 | Most paragraphs in your documentation will be ordinary blocks
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29 | of text, like this one. You can simply type in your text without
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30 | any markup whatsoever, and with just a blank line before and
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31 | after. When it gets formatted, it will undergo minimal formatting,
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32 | like being rewrapped, probably put into a proportionally spaced
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33 | font, and maybe even justified.
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34 |
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35 | You can use formatting codes in ordinary paragraphs, for B<bold>,
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36 | I<italic>, C<code-style>, L<hyperlinks|perlfaq>, and more. Such
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37 | codes are explained in the "L<Formatting Codes|/"Formatting Codes">"
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38 | section, below.
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39 |
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40 |
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41 | =head2 Verbatim Paragraph
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42 | X<POD, verbatim paragraph> X<verbatim>
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43 |
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44 | Verbatim paragraphs are usually used for presenting a codeblock or
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45 | other text which does not require any special parsing or formatting,
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46 | and which shouldn't be wrapped.
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47 |
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48 | A verbatim paragraph is distinguished by having its first character
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49 | be a space or a tab. (And commonly, all its lines begin with spaces
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50 | and/or tabs.) It should be reproduced exactly, with tabs assumed to
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51 | be on 8-column boundaries. There are no special formatting codes,
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52 | so you can't italicize or anything like that. A \ means \, and
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53 | nothing else.
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54 |
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55 |
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56 | =head2 Command Paragraph
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57 | X<POD, command>
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58 |
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59 | A command paragraph is used for special treatment of whole chunks
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60 | of text, usually as headings or parts of lists.
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61 |
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62 | All command paragraphs (which are typically only one line long) start
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63 | with "=", followed by an identifier, followed by arbitrary text that
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64 | the command can use however it pleases. Currently recognized commands
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65 | are
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66 |
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67 | =pod
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68 | =head1 Heading Text
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69 | =head2 Heading Text
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70 | =head3 Heading Text
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71 | =head4 Heading Text
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72 | =over indentlevel
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73 | =item stuff
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74 | =back
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75 | =begin format
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76 | =end format
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77 | =for format text...
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78 | =encoding type
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79 | =cut
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80 |
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81 | To explain them each in detail:
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82 |
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83 | =over
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84 |
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85 | =item C<=head1 I<Heading Text>>
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86 | X<=head1> X<=head2> X<=head3> X<=head4>
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87 | X<head1> X<head2> X<head3> X<head4>
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88 |
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89 | =item C<=head2 I<Heading Text>>
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90 |
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91 | =item C<=head3 I<Heading Text>>
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92 |
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93 | =item C<=head4 I<Heading Text>>
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94 |
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95 | Head1 through head4 produce headings, head1 being the highest
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96 | level. The text in the rest of this paragraph is the content of the
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97 | heading. For example:
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98 |
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99 | =head2 Object Attributes
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100 |
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101 | The text "Object Attributes" comprises the heading there. (Note that
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102 | head3 and head4 are recent additions, not supported in older Pod
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103 | translators.) The text in these heading commands can use
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104 | formatting codes, as seen here:
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105 |
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106 | =head2 Possible Values for C<$/>
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107 |
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108 | Such commands are explained in the
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109 | "L<Formatting Codes|/"Formatting Codes">" section, below.
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110 |
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111 | =item C<=over I<indentlevel>>
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112 | X<=over> X<=item> X<=back> X<over> X<item> X<back>
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113 |
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114 | =item C<=item I<stuff...>>
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115 |
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116 | =item C<=back>
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117 |
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118 | Item, over, and back require a little more explanation: "=over" starts
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119 | a region specifically for the generation of a list using "=item"
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120 | commands, or for indenting (groups of) normal paragraphs. At the end
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121 | of your list, use "=back" to end it. The I<indentlevel> option to
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122 | "=over" indicates how far over to indent, generally in ems (where
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123 | one em is the width of an "M" in the document's base font) or roughly
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124 | comparable units; if there is no I<indentlevel> option, it defaults
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125 | to four. (And some formatters may just ignore whatever I<indentlevel>
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126 | you provide.) In the I<stuff> in C<=item I<stuff...>>, you may
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127 | use formatting codes, as seen here:
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128 |
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129 | =item Using C<$|> to Control Buffering
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130 |
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131 | Such commands are explained in the
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132 | "L<Formatting Codes|/"Formatting Codes">" section, below.
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133 |
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134 | Note also that there are some basic rules to using "=over" ...
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135 | "=back" regions:
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136 |
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137 | =over
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138 |
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139 | =item *
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140 |
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141 | Don't use "=item"s outside of an "=over" ... "=back" region.
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142 |
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143 | =item *
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144 |
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145 | The first thing after the "=over" command should be an "=item", unless
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146 | there aren't going to be any items at all in this "=over" ... "=back"
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147 | region.
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148 |
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149 | =item *
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150 |
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151 | Don't put "=headI<n>" commands inside an "=over" ... "=back" region.
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152 |
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153 | =item *
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154 |
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155 | And perhaps most importantly, keep the items consistent: either use
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156 | "=item *" for all of them, to produce bullets; or use "=item 1.",
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157 | "=item 2.", etc., to produce numbered lists; or use "=item foo",
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158 | "=item bar", etc. -- namely, things that look nothing like bullets or
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159 | numbers.
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160 |
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161 | If you start with bullets or numbers, stick with them, as
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162 | formatters use the first "=item" type to decide how to format the
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163 | list.
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164 |
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165 | =back
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166 |
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167 | =item C<=cut>
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168 | X<=cut> X<cut>
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169 |
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170 | To end a Pod block, use a blank line,
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171 | then a line beginning with "=cut", and a blank
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172 | line after it. This lets Perl (and the Pod formatter) know that
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173 | this is where Perl code is resuming. (The blank line before the "=cut"
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174 | is not technically necessary, but many older Pod processors require it.)
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175 |
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176 | =item C<=pod>
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177 | X<=pod> X<pod>
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178 |
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179 | The "=pod" command by itself doesn't do much of anything, but it
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180 | signals to Perl (and Pod formatters) that a Pod block starts here. A
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181 | Pod block starts with I<any> command paragraph, so a "=pod" command is
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182 | usually used just when you want to start a Pod block with an ordinary
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183 | paragraph or a verbatim paragraph. For example:
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184 |
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185 | =item stuff()
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186 |
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187 | This function does stuff.
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188 |
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189 | =cut
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190 |
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191 | sub stuff {
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192 | ...
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193 | }
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194 |
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195 | =pod
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196 |
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197 | Remember to check its return value, as in:
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198 |
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199 | stuff() || die "Couldn't do stuff!";
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200 |
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201 | =cut
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202 |
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203 | =item C<=begin I<formatname>>
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204 | X<=begin> X<=end> X<=for> X<begin> X<end> X<for>
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205 |
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206 | =item C<=end I<formatname>>
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207 |
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208 | =item C<=for I<formatname> I<text...>>
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209 |
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210 | For, begin, and end will let you have regions of text/code/data that
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211 | are not generally interpreted as normal Pod text, but are passed
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212 | directly to particular formatters, or are otherwise special. A
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213 | formatter that can use that format will use the region, otherwise it
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214 | will be completely ignored.
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215 |
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216 | A command "=begin I<formatname>", some paragraphs, and a
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217 | command "=end I<formatname>", mean that the text/data inbetween
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218 | is meant for formatters that understand the special format
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219 | called I<formatname>. For example,
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220 |
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221 | =begin html
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222 |
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223 | <hr> <img src="thang.png">
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224 | <p> This is a raw HTML paragraph </p>
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225 |
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226 | =end html
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227 |
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228 | The command "=for I<formatname> I<text...>"
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229 | specifies that the remainder of just this paragraph (starting
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230 | right after I<formatname>) is in that special format.
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231 |
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232 | =for html <hr> <img src="thang.png">
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233 | <p> This is a raw HTML paragraph </p>
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234 |
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235 | This means the same thing as the above "=begin html" ... "=end html"
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236 | region.
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237 |
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238 | That is, with "=for", you can have only one paragraph's worth
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239 | of text (i.e., the text in "=foo targetname text..."), but with
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240 | "=begin targetname" ... "=end targetname", you can have any amount
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241 | of stuff inbetween. (Note that there still must be a blank line
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242 | after the "=begin" command and a blank line before the "=end"
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243 | command.
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244 |
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245 | Here are some examples of how to use these:
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246 |
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247 | =begin html
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248 |
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249 | <br>Figure 1.<br><IMG SRC="figure1.png"><br>
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250 |
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251 | =end html
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252 |
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253 | =begin text
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254 |
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255 | ---------------
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256 | | foo |
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257 | | bar |
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258 | ---------------
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259 |
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260 | ^^^^ Figure 1. ^^^^
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261 |
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262 | =end text
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263 |
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264 | Some format names that formatters currently are known to accept
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265 | include "roff", "man", "latex", "tex", "text", and "html". (Some
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266 | formatters will treat some of these as synonyms.)
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267 |
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268 | A format name of "comment" is common for just making notes (presumably
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269 | to yourself) that won't appear in any formatted version of the Pod
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270 | document:
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271 |
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272 | =for comment
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273 | Make sure that all the available options are documented!
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274 |
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275 | Some I<formatnames> will require a leading colon (as in
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276 | C<"=for :formatname">, or
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277 | C<"=begin :formatname" ... "=end :formatname">),
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278 | to signal that the text is not raw data, but instead I<is> Pod text
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279 | (i.e., possibly containing formatting codes) that's just not for
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280 | normal formatting (e.g., may not be a normal-use paragraph, but might
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281 | be for formatting as a footnote).
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282 |
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283 | =item C<=encoding I<encodingname>>
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284 | X<=encoding> X<encoding>
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285 |
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286 | This command is used for declaring the encoding of a document. Most
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287 | users won't need this; but if your encoding isn't US-ASCII or Latin-1,
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288 | then put a C<=encoding I<encodingname>> command early in the document so
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289 | that pod formatters will know how to decode the document. For
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290 | I<encodingname>, use a name recognized by the L<Encode::Supported>
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291 | module. Examples:
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292 |
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293 | =encoding utf8
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294 |
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295 | =encoding koi8-r
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296 |
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297 | =encoding ShiftJIS
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298 |
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299 | =encoding big5
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300 |
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301 | =back
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302 |
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303 | And don't forget, when using any command, that the command lasts up
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304 | until the end of its I<paragraph>, not its line. So in the
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305 | examples below, you can see that every command needs the blank
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306 | line after it, to end its paragraph.
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307 |
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308 | Some examples of lists include:
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309 |
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310 | =over
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311 |
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312 | =item *
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313 |
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314 | First item
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315 |
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316 | =item *
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317 |
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318 | Second item
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319 |
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320 | =back
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321 |
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322 | =over
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323 |
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324 | =item Foo()
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325 |
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326 | Description of Foo function
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327 |
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328 | =item Bar()
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329 |
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330 | Description of Bar function
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331 |
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332 | =back
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333 |
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334 |
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335 | =head2 Formatting Codes
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336 | X<POD, formatting code> X<formatting code>
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337 | X<POD, interior sequence> X<interior sequence>
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338 |
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339 | In ordinary paragraphs and in some command paragraphs, various
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340 | formatting codes (a.k.a. "interior sequences") can be used:
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341 |
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342 | =for comment
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343 | "interior sequences" is such an opaque term.
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344 | Prefer "formatting codes" instead.
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345 |
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346 | =over
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347 |
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348 | =item C<IE<lt>textE<gt>> -- italic text
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349 | X<I> X<< IZ<><> >> X<POD, formatting code, italic> X<italic>
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350 |
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351 | Used for emphasis ("C<be IE<lt>careful!E<gt>>") and parameters
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352 | ("C<redo IE<lt>LABELE<gt>>")
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353 |
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354 | =item C<BE<lt>textE<gt>> -- bold text
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355 | X<B> X<< BZ<><> >> X<POD, formatting code, bold> X<bold>
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356 |
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357 | Used for switches ("C<perl's BE<lt>-nE<gt> switch>"), programs
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358 | ("C<some systems provide a BE<lt>chfnE<gt> for that>"),
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359 | emphasis ("C<be BE<lt>careful!E<gt>>"), and so on
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360 | ("C<and that feature is known as BE<lt>autovivificationE<gt>>").
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361 |
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362 | =item C<CE<lt>codeE<gt>> -- code text
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363 | X<C> X<< CZ<><> >> X<POD, formatting code, code> X<code>
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364 |
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365 | Renders code in a typewriter font, or gives some other indication that
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366 | this represents program text ("C<CE<lt>gmtime($^T)E<gt>>") or some other
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367 | form of computerese ("C<CE<lt>drwxr-xr-xE<gt>>").
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368 |
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369 | =item C<LE<lt>nameE<gt>> -- a hyperlink
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370 | X<L> X<< LZ<><> >> X<POD, formatting code, hyperlink> X<hyperlink>
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371 |
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372 | There are various syntaxes, listed below. In the syntaxes given,
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373 | C<text>, C<name>, and C<section> cannot contain the characters
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374 | '/' and '|'; and any '<' or '>' should be matched.
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375 |
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376 | =over
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377 |
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378 | =item *
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379 |
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380 | C<LE<lt>nameE<gt>>
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381 |
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382 | Link to a Perl manual page (e.g., C<LE<lt>Net::PingE<gt>>). Note
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383 | that C<name> should not contain spaces. This syntax
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384 | is also occasionally used for references to UNIX man pages, as in
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385 | C<LE<lt>crontab(5)E<gt>>.
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386 |
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387 | =item *
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388 |
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389 | C<LE<lt>name/"sec"E<gt>> or C<LE<lt>name/secE<gt>>
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390 |
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391 | Link to a section in other manual page. E.g.,
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392 | C<LE<lt>perlsyn/"For Loops"E<gt>>
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393 |
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394 | =item *
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395 |
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396 | C<LE<lt>/"sec"E<gt>> or C<LE<lt>/secE<gt>> or C<LE<lt>"sec"E<gt>>
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397 |
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398 | Link to a section in this manual page. E.g.,
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399 | C<LE<lt>/"Object Methods"E<gt>>
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400 |
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401 | =back
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402 |
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403 | A section is started by the named heading or item. For
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404 | example, C<LE<lt>perlvar/$.E<gt>> or C<LE<lt>perlvar/"$."E<gt>> both
|
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405 | link to the section started by "C<=item $.>" in perlvar. And
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406 | C<LE<lt>perlsyn/For LoopsE<gt>> or C<LE<lt>perlsyn/"For Loops"E<gt>>
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407 | both link to the section started by "C<=head2 For Loops>"
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408 | in perlsyn.
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409 |
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410 | To control what text is used for display, you
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411 | use "C<LE<lt>text|...E<gt>>", as in:
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412 |
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413 | =over
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414 |
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415 | =item *
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416 |
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417 | C<LE<lt>text|nameE<gt>>
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418 |
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419 | Link this text to that manual page. E.g.,
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420 | C<LE<lt>Perl Error Messages|perldiagE<gt>>
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421 |
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422 | =item *
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423 |
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424 | C<LE<lt>text|name/"sec"E<gt>> or C<LE<lt>text|name/secE<gt>>
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425 |
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426 | Link this text to that section in that manual page. E.g.,
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427 | C<LE<lt>SWITCH statements|perlsyn/"Basic BLOCKs and Switch
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428 | Statements"E<gt>>
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429 |
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430 | =item *
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431 |
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432 | C<LE<lt>text|/"sec"E<gt>> or C<LE<lt>text|/secE<gt>>
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433 | or C<LE<lt>text|"sec"E<gt>>
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434 |
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435 | Link this text to that section in this manual page. E.g.,
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436 | C<LE<lt>the various attributes|/"Member Data"E<gt>>
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437 |
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438 | =back
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439 |
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440 | Or you can link to a web page:
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441 |
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442 | =over
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443 |
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444 | =item *
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445 |
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446 | C<LE<lt>scheme:...E<gt>>
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447 |
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448 | Links to an absolute URL. For example,
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449 | C<LE<lt>http://www.perl.org/E<gt>>. But note
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450 | that there is no corresponding C<LE<lt>text|scheme:...E<gt>> syntax, for
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451 | various reasons.
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452 |
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453 | =back
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454 |
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455 | =item C<EE<lt>escapeE<gt>> -- a character escape
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456 | X<E> X<< EZ<><> >> X<POD, formatting code, escape> X<escape>
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457 |
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458 | Very similar to HTML/XML C<&I<foo>;> "entity references":
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459 |
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460 | =over
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461 |
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462 | =item *
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463 |
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464 | C<EE<lt>ltE<gt>> -- a literal E<lt> (less than)
|
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465 |
|
---|
466 | =item *
|
---|
467 |
|
---|
468 | C<EE<lt>gtE<gt>> -- a literal E<gt> (greater than)
|
---|
469 |
|
---|
470 | =item *
|
---|
471 |
|
---|
472 | C<EE<lt>verbarE<gt>> -- a literal | (I<ver>tical I<bar>)
|
---|
473 |
|
---|
474 | =item *
|
---|
475 |
|
---|
476 | C<EE<lt>solE<gt>> = a literal / (I<sol>idus)
|
---|
477 |
|
---|
478 | The above four are optional except in other formatting codes,
|
---|
479 | notably C<LE<lt>...E<gt>>, and when preceded by a
|
---|
480 | capital letter.
|
---|
481 |
|
---|
482 | =item *
|
---|
483 |
|
---|
484 | C<EE<lt>htmlnameE<gt>>
|
---|
485 |
|
---|
486 | Some non-numeric HTML entity name, such as C<EE<lt>eacuteE<gt>>,
|
---|
487 | meaning the same thing as C<é> in HTML -- i.e., a lowercase
|
---|
488 | e with an acute (/-shaped) accent.
|
---|
489 |
|
---|
490 | =item *
|
---|
491 |
|
---|
492 | C<EE<lt>numberE<gt>>
|
---|
493 |
|
---|
494 | The ASCII/Latin-1/Unicode character with that number. A
|
---|
495 | leading "0x" means that I<number> is hex, as in
|
---|
496 | C<EE<lt>0x201EE<gt>>. A leading "0" means that I<number> is octal,
|
---|
497 | as in C<EE<lt>075E<gt>>. Otherwise I<number> is interpreted as being
|
---|
498 | in decimal, as in C<EE<lt>181E<gt>>.
|
---|
499 |
|
---|
500 | Note that older Pod formatters might not recognize octal or
|
---|
501 | hex numeric escapes, and that many formatters cannot reliably
|
---|
502 | render characters above 255. (Some formatters may even have
|
---|
503 | to use compromised renderings of Latin-1 characters, like
|
---|
504 | rendering C<EE<lt>eacuteE<gt>> as just a plain "e".)
|
---|
505 |
|
---|
506 | =back
|
---|
507 |
|
---|
508 | =item C<FE<lt>filenameE<gt>> -- used for filenames
|
---|
509 | X<F> X<< FZ<><> >> X<POD, formatting code, filename> X<filename>
|
---|
510 |
|
---|
511 | Typically displayed in italics. Example: "C<FE<lt>.cshrcE<gt>>"
|
---|
512 |
|
---|
513 | =item C<SE<lt>textE<gt>> -- text contains non-breaking spaces
|
---|
514 | X<S> X<< SZ<><> >> X<POD, formatting code, non-breaking space>
|
---|
515 | X<non-breaking space>
|
---|
516 |
|
---|
517 | This means that the words in I<text> should not be broken
|
---|
518 | across lines. Example: S<C<SE<lt>$x ? $y : $zE<gt>>>.
|
---|
519 |
|
---|
520 | =item C<XE<lt>topic nameE<gt>> -- an index entry
|
---|
521 | X<X> X<< XZ<><> >> X<POD, formatting code, index entry> X<index entry>
|
---|
522 |
|
---|
523 | This is ignored by most formatters, but some may use it for building
|
---|
524 | indexes. It always renders as empty-string.
|
---|
525 | Example: C<XE<lt>absolutizing relative URLsE<gt>>
|
---|
526 |
|
---|
527 | =item C<ZE<lt>E<gt>> -- a null (zero-effect) formatting code
|
---|
528 | X<Z> X<< ZZ<><> >> X<POD, formatting code, null> X<null>
|
---|
529 |
|
---|
530 | This is rarely used. It's one way to get around using an
|
---|
531 | EE<lt>...E<gt> code sometimes. For example, instead of
|
---|
532 | "C<NEE<lt>ltE<gt>3>" (for "NE<lt>3") you could write
|
---|
533 | "C<NZE<lt>E<gt>E<lt>3>" (the "ZE<lt>E<gt>" breaks up the "N" and
|
---|
534 | the "E<lt>" so they can't be considered
|
---|
535 | the part of a (fictitious) "NE<lt>...E<gt>" code.
|
---|
536 |
|
---|
537 | =for comment
|
---|
538 | This was formerly explained as a "zero-width character". But it in
|
---|
539 | most parser models, it parses to nothing at all, as opposed to parsing
|
---|
540 | as if it were a E<zwnj> or E<zwj>, which are REAL zero-width characters.
|
---|
541 | So "width" and "character" are exactly the wrong words.
|
---|
542 |
|
---|
543 | =back
|
---|
544 |
|
---|
545 | Most of the time, you will need only a single set of angle brackets to
|
---|
546 | delimit the beginning and end of formatting codes. However,
|
---|
547 | sometimes you will want to put a real right angle bracket (a
|
---|
548 | greater-than sign, '>') inside of a formatting code. This is particularly
|
---|
549 | common when using a formatting code to provide a different font-type for a
|
---|
550 | snippet of code. As with all things in Perl, there is more than
|
---|
551 | one way to do it. One way is to simply escape the closing bracket
|
---|
552 | using an C<E> code:
|
---|
553 |
|
---|
554 | C<$a E<lt>=E<gt> $b>
|
---|
555 |
|
---|
556 | This will produce: "C<$a E<lt>=E<gt> $b>"
|
---|
557 |
|
---|
558 | A more readable, and perhaps more "plain" way is to use an alternate
|
---|
559 | set of delimiters that doesn't require a single ">" to be escaped. With
|
---|
560 | the Pod formatters that are standard starting with perl5.5.660, doubled
|
---|
561 | angle brackets ("<<" and ">>") may be used I<if and only if there is
|
---|
562 | whitespace right after the opening delimiter and whitespace right
|
---|
563 | before the closing delimiter!> For example, the following will
|
---|
564 | do the trick:
|
---|
565 | X<POD, formatting code, escaping with multiple brackets>
|
---|
566 |
|
---|
567 | C<< $a <=> $b >>
|
---|
568 |
|
---|
569 | In fact, you can use as many repeated angle-brackets as you like so
|
---|
570 | long as you have the same number of them in the opening and closing
|
---|
571 | delimiters, and make sure that whitespace immediately follows the last
|
---|
572 | '<' of the opening delimiter, and immediately precedes the first '>'
|
---|
573 | of the closing delimiter. (The whitespace is ignored.) So the
|
---|
574 | following will also work:
|
---|
575 | X<POD, formatting code, escaping with multiple brackets>
|
---|
576 |
|
---|
577 | C<<< $a <=> $b >>>
|
---|
578 | C<<<< $a <=> $b >>>>
|
---|
579 |
|
---|
580 | And they all mean exactly the same as this:
|
---|
581 |
|
---|
582 | C<$a E<lt>=E<gt> $b>
|
---|
583 |
|
---|
584 | As a further example, this means that if you wanted to put these bits of
|
---|
585 | code in C<C> (code) style:
|
---|
586 |
|
---|
587 | open(X, ">>thing.dat") || die $!
|
---|
588 | $foo->bar();
|
---|
589 |
|
---|
590 | you could do it like so:
|
---|
591 |
|
---|
592 | C<<< open(X, ">>thing.dat") || die $! >>>
|
---|
593 | C<< $foo->bar(); >>
|
---|
594 |
|
---|
595 | which is presumably easier to read than the old way:
|
---|
596 |
|
---|
597 | C<open(X, "E<gt>E<gt>thing.dat") || die $!>
|
---|
598 | C<$foo-E<gt>bar();>
|
---|
599 |
|
---|
600 | This is currently supported by pod2text (Pod::Text), pod2man (Pod::Man),
|
---|
601 | and any other pod2xxx or Pod::Xxxx translators that use
|
---|
602 | Pod::Parser 1.093 or later, or Pod::Tree 1.02 or later.
|
---|
603 |
|
---|
604 | =head2 The Intent
|
---|
605 | X<POD, intent of>
|
---|
606 |
|
---|
607 | The intent is simplicity of use, not power of expression. Paragraphs
|
---|
608 | look like paragraphs (block format), so that they stand out
|
---|
609 | visually, and so that I could run them through C<fmt> easily to reformat
|
---|
610 | them (that's F7 in my version of B<vi>, or Esc Q in my version of
|
---|
611 | B<emacs>). I wanted the translator to always leave the C<'> and C<`> and
|
---|
612 | C<"> quotes alone, in verbatim mode, so I could slurp in a
|
---|
613 | working program, shift it over four spaces, and have it print out, er,
|
---|
614 | verbatim. And presumably in a monospace font.
|
---|
615 |
|
---|
616 | The Pod format is not necessarily sufficient for writing a book. Pod
|
---|
617 | is just meant to be an idiot-proof common source for nroff, HTML,
|
---|
618 | TeX, and other markup languages, as used for online
|
---|
619 | documentation. Translators exist for B<pod2text>, B<pod2html>,
|
---|
620 | B<pod2man> (that's for nroff(1) and troff(1)), B<pod2latex>, and
|
---|
621 | B<pod2fm>. Various others are available in CPAN.
|
---|
622 |
|
---|
623 |
|
---|
624 | =head2 Embedding Pods in Perl Modules
|
---|
625 | X<POD, embedding>
|
---|
626 |
|
---|
627 | You can embed Pod documentation in your Perl modules and scripts.
|
---|
628 | Start your documentation with an empty line, a "=head1" command at the
|
---|
629 | beginning, and end it with a "=cut" command and an empty line. Perl
|
---|
630 | will ignore the Pod text. See any of the supplied library modules for
|
---|
631 | examples. If you're going to put your Pod at the end of the file, and
|
---|
632 | you're using an __END__ or __DATA__ cut mark, make sure to put an
|
---|
633 | empty line there before the first Pod command.
|
---|
634 |
|
---|
635 | __END__
|
---|
636 |
|
---|
637 | =head1 NAME
|
---|
638 |
|
---|
639 | Time::Local - efficiently compute time from local and GMT time
|
---|
640 |
|
---|
641 | Without that empty line before the "=head1", many translators wouldn't
|
---|
642 | have recognized the "=head1" as starting a Pod block.
|
---|
643 |
|
---|
644 | =head2 Hints for Writing Pod
|
---|
645 |
|
---|
646 | =over
|
---|
647 |
|
---|
648 | =item *
|
---|
649 | X<podchecker> X<POD, validating>
|
---|
650 |
|
---|
651 | The B<podchecker> command is provided for checking Pod syntax for errors
|
---|
652 | and warnings. For example, it checks for completely blank lines in
|
---|
653 | Pod blocks and for unknown commands and formatting codes. You should
|
---|
654 | still also pass your document through one or more translators and proofread
|
---|
655 | the result, or print out the result and proofread that. Some of the
|
---|
656 | problems found may be bugs in the translators, which you may or may not
|
---|
657 | wish to work around.
|
---|
658 |
|
---|
659 | =item *
|
---|
660 |
|
---|
661 | If you're more familiar with writing in HTML than with writing in Pod, you
|
---|
662 | can try your hand at writing documentation in simple HTML, and converting
|
---|
663 | it to Pod with the experimental L<Pod::HTML2Pod|Pod::HTML2Pod> module,
|
---|
664 | (available in CPAN), and looking at the resulting code. The experimental
|
---|
665 | L<Pod::PXML|Pod::PXML> module in CPAN might also be useful.
|
---|
666 |
|
---|
667 | =item *
|
---|
668 |
|
---|
669 | Many older Pod translators require the lines before every Pod
|
---|
670 | command and after every Pod command (including "=cut"!) to be a blank
|
---|
671 | line. Having something like this:
|
---|
672 |
|
---|
673 | # - - - - - - - - - - - -
|
---|
674 | =item $firecracker->boom()
|
---|
675 |
|
---|
676 | This noisily detonates the firecracker object.
|
---|
677 | =cut
|
---|
678 | sub boom {
|
---|
679 | ...
|
---|
680 |
|
---|
681 | ...will make such Pod translators completely fail to see the Pod block
|
---|
682 | at all.
|
---|
683 |
|
---|
684 | Instead, have it like this:
|
---|
685 |
|
---|
686 | # - - - - - - - - - - - -
|
---|
687 |
|
---|
688 | =item $firecracker->boom()
|
---|
689 |
|
---|
690 | This noisily detonates the firecracker object.
|
---|
691 |
|
---|
692 | =cut
|
---|
693 |
|
---|
694 | sub boom {
|
---|
695 | ...
|
---|
696 |
|
---|
697 | =item *
|
---|
698 |
|
---|
699 | Some older Pod translators require paragraphs (including command
|
---|
700 | paragraphs like "=head2 Functions") to be separated by I<completely>
|
---|
701 | empty lines. If you have an apparently empty line with some spaces
|
---|
702 | on it, this might not count as a separator for those translators, and
|
---|
703 | that could cause odd formatting.
|
---|
704 |
|
---|
705 | =item *
|
---|
706 |
|
---|
707 | Older translators might add wording around an LE<lt>E<gt> link, so that
|
---|
708 | C<LE<lt>Foo::BarE<gt>> may become "the Foo::Bar manpage", for example.
|
---|
709 | So you shouldn't write things like C<the LE<lt>fooE<gt>
|
---|
710 | documentation>, if you want the translated document to read sensibly
|
---|
711 | -- instead write C<the LE<lt>Foo::Bar|Foo::BarE<gt> documentation> or
|
---|
712 | C<LE<lt>the Foo::Bar documentation|Foo::BarE<gt>>, to control how the
|
---|
713 | link comes out.
|
---|
714 |
|
---|
715 | =item *
|
---|
716 |
|
---|
717 | Going past the 70th column in a verbatim block might be ungracefully
|
---|
718 | wrapped by some formatters.
|
---|
719 |
|
---|
720 | =back
|
---|
721 |
|
---|
722 | =head1 SEE ALSO
|
---|
723 |
|
---|
724 | L<perlpodspec>, L<perlsyn/"PODs: Embedded Documentation">,
|
---|
725 | L<perlnewmod>, L<perldoc>, L<pod2html>, L<pod2man>, L<podchecker>.
|
---|
726 |
|
---|
727 | =head1 AUTHOR
|
---|
728 |
|
---|
729 | Larry Wall, Sean M. Burke
|
---|
730 |
|
---|
731 | =cut
|
---|