A pod-to-whatever translator reads a pod file paragraph by paragraph, and translates it to the appropriate output format. There are three kinds of paragraphs: verbatim, command, and ordinary text.
A verbatim paragraph, distinguished by being indented (that is, it starts with space or tab). It should be reproduced exactly, with tabs assumed to be on 8-column boundaries. There are no special formatting escapes, so you can't italicize or anything like that. A \ means , and nothing else.
All command paragraphs start with ``='', followed by an identifier, followed by arbitrary text that the command can use however it pleases. Currently recognized commands are
=head2 heading =item text =over N =back =cut =pod =for X =begin X =end X =pod
The ``=pod directive does nothing beyond telling the compiler to lay off parsing code through the next ``=cut. It's useful for adding another paragraph to the doc if you're mixing up code and pod a lot.
Head1 and head2 produce first and second level headings, with the text in the same paragraph as the ``=headn'' directive forming the heading description.
Item, over, and back require a little more explanation: ``=over starts a section specifically for the generation of a list using ``=item commands. At the end of your list, use ``=back to end it. You will probably want to give ``4 as the number to ``=over, as some formatters will use this for indentation. The unit of indentation is optional. If the unit is not given the natural indentation of the formatting system applied will be used. Note also that there are some basic rules to using =item: don't use them outside of an =over/=back block, use at least one inside an =over/=back block, you don't have to include the =back if the list just runs off the document, and perhaps most importantly, keep the items consistent: either use ``=item * for all of them, to produce bullets, or use ``=item 1., ``=item 2., etc., to produce numbered lists, or use ``=item foo, ``=item bar, etc., i.e., things that looks nothing like bullets or numbers. If you start with bullets or numbers, stick with them, as many formatters use the first ``=item'' type to decide how to format the list.
The paired commands ``=begin and ``=end work very similarly to ``=for, but instead of only accepting a single paragraph, all text from ``=begin to a paragraph with a matching ``=end'' are treated as a particular format.
Some format names that formatters currently are known to accept include ``roff, ``man, ``latex, ``tex, ``text, and ``html. (Some formatters will treat some of these as synonyms.)
And don't forget, when using any command, that the command lasts up until the end of the paragraph, not the line. Hence in the examples below, you can see the empty lines after each command to end its paragraph.
Ordinary Block of Text
This will produce: $a
In fact, you can use as many repeated angle-brackets as you like so long as you have the same number of them in the opening and closing delimiters, and make sure that whitespace immediately follows the last '
This is currently supported by pod2text (Pod::Text), pod2man (Pod::Man), and any other pod2xxx and Pod::Xxxx translator that uses Pod::Parser 1.093 or later.
That's it. The intent is simplicity, not power. I wanted paragraphs to look like paragraphs (block format), so that they stand out visually, and so that I could run them through fmt easily to reformat them (that's F7 in my version of vi). I wanted the translator (and not me) to worry about whether __
FILEHANDLE $variable function() manpage(3r)? Doubtless a few other commands or sequences will need to be added along the way, but I've gotten along surprisingly well with just these.
Note that I'm not at all claiming this to be sufficient for producing a book. I'm just trying to make an idiot-proof common source for nroff, TeX, and other markup languages, as used for online documentation. Translators exist for pod2man (that's for nroff(1) and troff(1)), pod2text, pod2html, pod2latex, and pod2fm.
Embedding Pods in Perl Modules
You can embed pod documentation in your Perl scripts. Start your documentation with a ``=head1 command at the beginning, and end it with a ``=cut command. Perl will ignore the pod text. See any of the supplied library modules for examples. If you're going to put your pods at the end of the file, and you're using an END or DATA cut mark, make sure to put an empty line there before the first pod directive.
If you had not had that empty line there, then the translators wouldn't have seen it.
Common Pod Pitfalls
Pod translators usually will require paragraphs to be separated by completely empty lines. If you have an apparently empty line with some spaces on it, this can cause odd formatting.
Translators will mostly add wording around a L L becomes foo(1) manpagepod2man__ for details). Thus, you shouldn't write things like the L, if you want the translated document to read sensibly.
If you need total control of the text used for a link in the output use the form L