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1=head1 NAME
2
3perlpod - plain old documentation
4
5=head1 DESCRIPTION
6
7A pod-to-whatever translator reads a pod file paragraph by paragraph,
8and translates it to the appropriate output format. There are
9three kinds of paragraphs:
10
11=over 4
12
13=item *
14
15A verbatim paragraph, distinguished by being indented (that is,
16it starts with space or tab). It should be reproduced exactly,
17with tabs assumed to be on 8-column boundaries. There are no
18special formatting escapes, so you can't italicize or anything
19like that. A \ means \, and nothing else.
20
21=item *
22
23A command. All command paragraphs start with "=", followed by an
24identifier, followed by arbitrary text that the command can
25use however it pleases. Currently recognized commands are
26
27 =head1 heading
28 =head2 heading
29 =item text
30 =over N
31 =back
32 =cut
33 =pod
34
35The "=pod" directive does nothing beyond telling the compiler to lay
36off of through the next "=cut". It's useful for adding another
37paragraph to the doc if you're mixing up code and pod a lot.
38
39Head1 and head2 produce first and second level headings, with the text on
40the same paragraph as "=headn" forming the heading description.
41
42Item, over, and back require a little more explanation: Over starts a
43section specifically for the generation of a list using =item commands. At
44the end of your list, use =back to end it. You will probably want to give
45"4" as the number to =over, as some formatters will use this for indentation.
46This should probably be a default. Note also that there are some basic rules
47to using =item: don't use them outside of an =over/=back block, use at least
48one inside an =over/=back block, you don't _have_ to include the =back if
49the list just runs off the document, and perhaps most importantly, keep the
50items consistent: either use "=item *" for all of them, to produce bullets,
51or use "=item 1.", "=item 2.", etc., to produce numbered lists, or use
52"=item foo", "=item bar", etc., i.e., things that looks nothing like bullets
53or numbers. If you start with bullets or numbers, stick with them, as many
54formatters use the first =item type to decide how to format the list.
55
56And don't forget, when using any command, that that command lasts up until
57the end of the B<paragraph>, not the line. Hence in the examples below, you
58can see the blank lines after each command to end its paragraph.
59
60Some examples of lists include:
61
62 =over 4
63
64 =item *
65
66 First item
67
68 =item *
69
70 Second item
71
72 =back
73
74 =over 4
75
76 =item Foo()
77
78 Description of Foo function
79
80 =item Bar()
81
82 Description of Bar function
83
84 =back
85
86=item *
87
88An ordinary block of text. It will be filled, and maybe even
89justified. Certain interior sequences are recognized both
90here and in commands:
91
92 I<text> italicize text, used for emphasis or variables
93 B<text> embolden text, used for switches and programs
94 S<text> text contains non-breaking spaces
95 C<code> literal code
96 L<name> A link (cross reference) to name
97 L<name> manpage
98 L<name/ident> item in manpage
99 L<name/"sec"> section in other manpage
100 L<"sec"> section in this manpage
101 (the quotes are optional)
102 L</"sec"> ditto
103 F<file> Used for filenames
104 X<index> An index entry
105 Z<> A zero-width character
106 E<escape> An HTML escape
107 E<lt> A literal <
108 E<gt> A literal >
109 (these are optional except in other interior
110 sequences and when preceded by a capital letter)
111 E<nnn> Character number nnn.
112
113=back
114
115That's it. The intent is simplicity, not power. I wanted paragraphs
116to look like paragraphs (block format), so that they stand out
117visually, and so that I could run them through fmt easily to reformat
118them (that's F7 in my version of B<vi>). I wanted the translator (and not
119me) to worry about whether " or ' is a left quote or a right quote
120within filled text, and I wanted it to leave the quotes alone dammit in
121verbatim mode, so I could slurp in a working program, shift it over 4
122spaces, and have it print out, er, verbatim. And presumably in a
123constant width font.
124
125In particular, you can leave things like this verbatim in your text:
126
127 Perl
128 FILEHANDLE
129 $variable
130 function()
131 manpage(3r)
132
133Doubtless a few other commands or sequences will need to be added along
134the way, but I've gotten along surprisingly well with just these.
135
136Note that I'm not at all claiming this to be sufficient for producing a
137book. I'm just trying to make an idiot-proof common source for nroff,
138TeX, and other markup languages, as used for online documentation.
139Translators exist for B<pod2man> (that's for nroff(1) and troff(1)),
140B<pod2html>, B<pod2latex>, and B<pod2fm>.
141
142=head1 Embedding Pods in Perl Modules
143
144You can embed pod documentation in your Perl scripts. Start your
145documentation with a =head1 command at the beg, and end it with
146an =cut command. Perl will ignore the pod text. See any of the
147supplied library modules for examples. If you're going to put
148your pods at the end of the file, and you're using an __END__
149or __DATA__ cut mark, make sure to put a blank line there before
150the first pod directive.
151
152 __END__
153
154 =head1 NAME
155
156 modern - I am a modern module
157
158If you had not had that blank line there, then the translators wouldn't
159have seen it.
160
161=head1 Common Pod Pitfalls
162
163=over 4
164
165=item *
166
167Pod translators usually will require paragraphs to be separated by
168completely empty lines. If you have an apparently blank line with
169some spaces on it, this can cause odd formatting.
170
171=item *
172
173Translators will mostly add wording around a LE<lt>E<gt> link, so that
174C<LE<lt>foo(1)E<gt>> becomes "the I<foo>(1) manpage", for example (see
175B<pod2man> for details). Thus, you shouldn't write things like C<the
176LE<lt>fooE<gt> manpage>, if you want the translated document to read
177sensibly.
178
179=item *
180
181The script F<pod/checkpods.PL> in the Perl source distribution
182provides skeletal checking for lines that look blank but aren't
183B<only>, but is there as a placeholder until someone writes
184Pod::Checker. The best way to check your pod is to pass it through
185one or more translators and proofread the result, or print out the
186result and proofread that. Some of the problems found may be bugs in
187the translators, which you may or may not wish to work around.
188
189=back
190
191=head1 SEE ALSO
192
193L<pod2man> and L<perlsyn/"PODs: Embedded Documentation">
194
195=head1 AUTHOR
196
197Larry Wall
198