source: trunk/essentials/dev-lang/perl/pod/perlpod.pod@ 3439

=for comment
This document is in Pod format.  To read this, use a Pod formatter,
like "perldoc perlpod".

=head1 NAME
X<POD> X<plain old documentation>

perlpod - the Plain Old Documentation format

=head1 DESCRIPTION

Pod is a simple-to-use markup language used for writing documentation
for Perl, Perl programs, and Perl modules.

Translators are available for converting Pod to various formats
like plain text, HTML, man pages, and more.

Pod markup consists of three basic kinds of paragraphs:
L<ordinary|/"Ordinary Paragraph">,
L<verbatim|/"Verbatim Paragraph">, and 
L<command|/"Command Paragraph">.


=head2 Ordinary Paragraph
X<POD, ordinary paragraph>

Most paragraphs in your documentation will be ordinary blocks
of text, like this one.  You can simply type in your text without
any markup whatsoever, and with just a blank line before and
after.  When it gets formatted, it will undergo minimal formatting, 
like being rewrapped, probably put into a proportionally spaced
font, and maybe even justified.

You can use formatting codes in ordinary paragraphs, for B<bold>,
I<italic>, C<code-style>, L<hyperlinks|perlfaq>, and more.  Such
codes are explained in the "L<Formatting Codes|/"Formatting Codes">"
section, below.


=head2 Verbatim Paragraph
X<POD, verbatim paragraph> X<verbatim>

Verbatim paragraphs are usually used for presenting a codeblock or
other text which does not require any special parsing or formatting,
and which shouldn't be wrapped.

A verbatim paragraph is distinguished by having its first character
be a space or a tab.  (And commonly, all its lines begin with spaces
and/or tabs.)  It should be reproduced exactly, with tabs assumed to
be on 8-column boundaries.  There are no special formatting codes,
so you can't italicize or anything like that.  A \ means \, and
nothing else.


=head2 Command Paragraph
X<POD, command>

A command paragraph is used for special treatment of whole chunks
of text, usually as headings or parts of lists.

All command paragraphs (which are typically only one line long) start
with "=", followed by an identifier, followed by arbitrary text that
the command can use however it pleases.  Currently recognized commands
are

    =pod
    =head1 Heading Text
    =head2 Heading Text
    =head3 Heading Text
    =head4 Heading Text
    =over indentlevel
    =item stuff
    =back
    =begin format
    =end format
    =for format text...
    =encoding type
    =cut

To explain them each in detail:

=over

=item C<=head1 I<Heading Text>>
X<=head1> X<=head2> X<=head3> X<=head4>
X<head1> X<head2> X<head3> X<head4>

=item C<=head2 I<Heading Text>>

=item C<=head3 I<Heading Text>>

=item C<=head4 I<Heading Text>>

Head1 through head4 produce headings, head1 being the highest
level.  The text in the rest of this paragraph is the content of the
heading.  For example:

  =head2 Object Attributes

The text "Object Attributes" comprises the heading there.  (Note that
head3 and head4 are recent additions, not supported in older Pod
translators.)  The text in these heading commands can use
formatting codes, as seen here:

  =head2 Possible Values for C<$/>

Such commands are explained in the
"L<Formatting Codes|/"Formatting Codes">" section, below.

=item C<=over I<indentlevel>>
X<=over> X<=item> X<=back> X<over> X<item> X<back>

=item C<=item I<stuff...>>

=item C<=back>

Item, over, and back require a little more explanation:  "=over" starts
a region specifically for the generation of a list using "=item"
commands, or for indenting (groups of) normal paragraphs.  At the end
of your list, use "=back" to end it.  The I<indentlevel> option to
"=over" indicates how far over to indent, generally in ems (where
one em is the width of an "M" in the document's base font) or roughly
comparable units; if there is no I<indentlevel> option, it defaults
to four.  (And some formatters may just ignore whatever I<indentlevel>
you provide.)  In the I<stuff> in C<=item I<stuff...>>, you may
use formatting codes, as seen here:

  =item Using C<$|> to Control Buffering

Such commands are explained in the