Current Perl documentation can be found at perldoc.perl.org.
Here is our local, out-dated (pre-5.6) version:
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.
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
=head1 heading =head2 heading =item text =over N =back =cut =pod =for X =begin X =end X
=for html <br> <p> This is a raw HTML paragraph </p>
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.
Here are some examples of how to use these:
<br>Figure 1.<IMG SRC="figure1.png"><br>
--------------- | foo | | bar | ---------------
^^^^ Figure 1. ^^^^
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.
Some examples of lists include:
Description of Foo function
Description of Bar function
It will be filled, and maybe even justified. Certain interior sequences are recognized both here and in commands:
I<text> italicize text, used for emphasis or variables B<text> embolden text, used for switches and programs S<text> text contains non-breaking spaces C<code> literal code L<name> A link (cross reference) to name L<name> manual page L<name/ident> item in manual page L<name/"sec"> section in other manual page L<"sec"> section in this manual page (the quotes are optional) L</"sec"> ditto same as above but only 'text' is used for output. (Text can not contain the characters '|' or '>') L<text|name> L<text|name/ident> L<text|name/"sec"> L<text|"sec"> L<text|/"sec"> F<file> Used for filenames X<index> An index entry Z<> A zero-width character &escape; A named character (very similar to HTML escapes) < A literal < > A literal > (these are optional except in other interior sequences and when preceded by a capital letter) &n; Character number n (probably in ASCII) &html; Some non-numeric HTML entity, such as À
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 `` or ' is a left quote or a right quote within filled text, and I wanted it to leave the quotes alone, dammit, in verbatim mode, so I could slurp in a working program, shift it over 4 spaces, and have it print out, er, verbatim. And presumably in a constant width font.
In particular, you can leave things like this verbatim in your text:
Perl 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
pod2text, pod2html, pod2latex, and pod2fm.
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.
modern - I am a modern module
If you had not had that empty line there, then the translators wouldn't have seen it.
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.
L<foo(1)>becomes ``the foo(1) manpage'', for example (see pod2man for details). Thus, you shouldn't write things like
the L<foo> manpage, if you want the translated document to read sensibly.
If you don need or want total control of the text used for a link in the output use the form L<show this text|foo> instead.
the pod2man manpage and perlman:perlsyn