PERLPOD
NAME DESCRIPTION SEE ALSO AUTHOR
perlpod - plain old documentation
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.
Verbatim Paragraph
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.
Command Paragraph
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
=head1 heading
=head2 heading =item text =over N =back =cut =pod =for X =begin X =end X =pod
=cut
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
=head2
Head1 and head2 produce first and second level headings, with the text in the same paragraph as the ``=headn'' directive forming the heading description.
=over
=back
=item
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.
=for
=begin
=end
For, begin, and end let you include sections that are not interpreted as pod text, but passed directly to particular formatters. A formatter that can utilize that format will use the section, otherwise it will be completely ignored. The directive ``=for'' specifies that the entire next paragraph is in the format indicated by the first word after
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.
=begin html
=end html =begin text
foo bar
^^^^ Figure 1. ^^^^ =end text
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
It will be filled, and maybe even justified. Certain interior sequences are recognized both here and in
This will produce: $a
A more readable, and perhaps more ``plain way is to use an alternate set of delimiters that doesn't require a `` if and only if there is whitespace immediately following the opening delimiter and immediately preceding the closing delimiter! For example, the following will do the
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 '
C
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.
The Intent
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 __
In particular, you can leave things like this verbatim in
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.
END =head1 NAME modern - I am a modern module
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
The podchecker command is provided to check pod syntax for errors and warnings. For example, it checks for completely blank lines in pod segments and for unknown escape sequences. It is still advised to pass it through one or more translators and proofread the result, or print out the result and proofread that. Some of the problems found may be bugs in the translators, which you may or may not wish to work around.
pod2man, ``PODs: Embedded Documentation'' in perlsyn, podchecker
Larry Wall
2 pages link to perlpod(1):
