3 perlpod - plain old documentation
7 A pod-to-whatever translator reads a pod file paragraph by paragraph,
8 and translates it to the appropriate output format. There are
9 three kinds of paragraphs:
10 L<verbatim|/"Verbatim Paragraph">,
11 L<command|/"Command Paragraph">, and
12 L<ordinary text|/"Ordinary Block of Text">.
15 =head2 Verbatim Paragraph
17 A verbatim paragraph, distinguished by being indented (that is,
18 it starts with space or tab). It should be reproduced exactly,
19 with tabs assumed to be on 8-column boundaries. There are no
20 special formatting escapes, so you can't italicize or anything
21 like that. A \ means \, and nothing else.
24 =head2 Command Paragraph
26 All command paragraphs start with "=", followed by an
27 identifier, followed by arbitrary text that the command can
28 use however it pleases. Currently recognized commands are
47 The "=pod" directive does nothing beyond telling the compiler to lay
48 off parsing code through the next "=cut". It's useful for adding
49 another paragraph to the doc if you're mixing up code and pod a lot.
55 Head1 and head2 produce first and second level headings, with the text in
56 the same paragraph as the "=headn" directive forming the heading description.
64 Item, over, and back require a little more explanation: "=over" starts a
65 section specifically for the generation of a list using "=item" commands. At
66 the end of your list, use "=back" to end it. You will probably want to give
67 "4" as the number to "=over", as some formatters will use this for indentation.
68 This should probably be a default. Note also that there are some basic rules
69 to using =item: don't use them outside of an =over/=back block, use at least
70 one inside an =over/=back block, you don't _have_ to include the =back if
71 the list just runs off the document, and perhaps most importantly, keep the
72 items consistent: either use "=item *" for all of them, to produce bullets,
73 or use "=item 1.", "=item 2.", etc., to produce numbered lists, or use
74 "=item foo", "=item bar", etc., i.e., things that looks nothing like bullets
75 or numbers. If you start with bullets or numbers, stick with them, as many
76 formatters use the first "=item" type to decide how to format the list.
85 For, begin, and end let you include sections that are not interpreted
86 as pod text, but passed directly to particular formatters. A formatter
87 that can utilize that format will use the section, otherwise it will be
88 completely ignored. The directive "=for" specifies that the entire next
89 paragraph is in the format indicated by the first word after
93 <p> This is a raw HTML paragraph </p>
95 The paired commands "=begin" and "=end" work very similarly to "=for", but
96 instead of only accepting a single paragraph, all text from "=begin" to a
97 paragraph with a matching "=end" are treated as a particular format.
99 Here are some examples of how to use these:
103 <br>Figure 1.<IMG SRC="figure1.png"><br>
118 Some format names that formatters currently are known to accept include
119 "roff", "man", "latex", "tex", "text", and "html". (Some formatters will
120 treat some of these as synonyms.)
122 And don't forget, when using any command, that the command lasts up until
123 the end of the B<paragraph>, not the line. Hence in the examples below, you
124 can see the empty lines after each command to end its paragraph.
126 Some examples of lists include:
144 Description of Foo function
148 Description of Bar function
156 =head2 Ordinary Block of Text
158 It will be filled, and maybe even
159 justified. Certain interior sequences are recognized both
160 here and in commands:
162 I<text> italicize text, used for emphasis or variables
163 B<text> embolden text, used for switches and programs
164 S<text> text contains non-breaking spaces
166 L<name> A link (cross reference) to name
168 L<name/ident> item in manual page
169 L<name/"sec"> section in other manual page
170 L<"sec"> section in this manual page
171 (the quotes are optional)
173 same as above but only 'text' is used for output.
174 (Text can not contain the characters '|' or '>')
181 F<file> Used for filenames
182 X<index> An index entry
183 Z<> A zero-width character
184 E<escape> A named character (very similar to HTML escapes)
187 (these are optional except in other interior
188 sequences and when preceded by a capital letter)
189 E<n> Character number n (probably in ASCII)
190 E<html> Some non-numeric HTML entity, such
196 That's it. The intent is simplicity, not power. I wanted paragraphs
197 to look like paragraphs (block format), so that they stand out
198 visually, and so that I could run them through fmt easily to reformat
199 them (that's F7 in my version of B<vi>). I wanted the translator (and not
200 me) to worry about whether " or ' is a left quote or a right quote
201 within filled text, and I wanted it to leave the quotes alone, dammit, in
202 verbatim mode, so I could slurp in a working program, shift it over 4
203 spaces, and have it print out, er, verbatim. And presumably in a
206 In particular, you can leave things like this verbatim in your text:
214 Doubtless a few other commands or sequences will need to be added along
215 the way, but I've gotten along surprisingly well with just these.
217 Note that I'm not at all claiming this to be sufficient for producing a
218 book. I'm just trying to make an idiot-proof common source for nroff,
219 TeX, and other markup languages, as used for online documentation.
220 Translators exist for B<pod2man> (that's for nroff(1) and troff(1)),
221 B<pod2text>, B<pod2html>, B<pod2latex>, and B<pod2fm>.
224 =head2 Embedding Pods in Perl Modules
226 You can embed pod documentation in your Perl scripts. Start your
227 documentation with a "=head1" command at the beginning, and end it
228 with a "=cut" command. Perl will ignore the pod text. See any of the
229 supplied library modules for examples. If you're going to put your
230 pods at the end of the file, and you're using an __END__ or __DATA__
231 cut mark, make sure to put an empty line there before the first pod
239 modern - I am a modern module
241 If you had not had that empty line there, then the translators wouldn't
245 =head2 Common Pod Pitfalls
251 Pod translators usually will require paragraphs to be separated by
252 completely empty lines. If you have an apparently empty line with
253 some spaces on it, this can cause odd formatting.
257 Translators will mostly add wording around a LE<lt>E<gt> link, so that
258 C<LE<lt>foo(1)E<gt>> becomes "the I<foo>(1) manpage", for example (see
259 B<pod2man> for details). Thus, you shouldn't write things like C<the
260 LE<lt>fooE<gt> manpage>, if you want the translated document to read
263 If you don need or want total control of the text used for a
264 link in the output use the form LE<lt>show this text|fooE<gt>
269 The script F<pod/checkpods.PL> in the Perl source distribution
270 provides skeletal checking for lines that look empty but aren't
271 B<only>, but is there as a placeholder until someone writes
272 Pod::Checker. The best way to check your pod is to pass it through
273 one or more translators and proofread the result, or print out the
274 result and proofread that. Some of the problems found may be bugs in
275 the translators, which you may or may not wish to work around.
281 L<pod2man> and L<perlsyn/"PODs: Embedded Documentation">