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:
+L<verbatim|/"Verbatim Paragraph">,
+L<command|/"Command Paragraph">, and
+L<ordinary text|/"Ordinary Block of Text">.
-=over 4
-
-=item *
+=head2 Verbatim Paragraph
A verbatim paragraph, distinguished by being indented (that is,
it starts with space or tab). It should be reproduced exactly,
special formatting escapes, so you can't italicize or anything
like that. A \ means \, and nothing else.
-=item *
+=head2 Command Paragraph
-A command. All command paragraphs start with "=", followed by an
+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
+ =head3 heading
+ =head4 heading
=item text
=over N
=back
=begin X
=end X
+=over 4
+
+=item =pod
+
+=item =cut
+
The "=pod" directive does nothing beyond telling the compiler to lay
-off of 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 on
-the same paragraph as "=headn" 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.
-This should probably be a default. 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 and begin/end let you include sections that are not interpreted as pod
-text, but in a format that a particular formatter is looking for. A
-formatter that can utilize that format will use the section, otherwise it
-will be completely ignored. "=for" specifies that the entire paragraph
-should is in the format indicated by the first word after "=for", like this:
-
- =for html <br>
+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.
+
+=item =head1
+
+=item =head2
+
+=item =head3
+
+=item =head4
+
+Head1, head2, head3 and head4 produce first, second, third and fourth
+level headings, with the text in the same paragraph as the "=headn"
+directive forming the heading description.
+
+=item =over
+
+=item =back
+
+=item =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.
+
+=item =for
+
+=item =begin
+
+=item =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
+"=for", like this:
+
+ =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.
+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:
"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 that command lasts up until
+And don't forget, when using any command, that the command lasts up until
the end of the B<paragraph>, not the line. Hence in the examples below, you
-can see the blank lines after each command to end its paragraph.
+can see the empty lines after each command to end its paragraph.
Some examples of lists include:
=back
-=item *
+=back
-An ordinary block of text. It will be filled, and maybe even
+=head2 Ordinary Block of Text
+
+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
+ 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> Render code in a typewriter font, or give some other
+ indication that this represents program text
L<name> A link (cross reference) to name
L<name> manual page
L<name/ident> item in 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 '/' and '|',
+ and should contain matched '<' 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
+ Z<> A zero-width character
E<escape> A named character (very similar to HTML escapes)
E<lt> A literal <
E<gt> A literal >
+ E<sol> A literal /
+ E<verbar> A literal |
(these are optional except in other interior
sequences and when preceded by a capital letter)
E<n> Character number n (probably in ASCII)
E<html> Some non-numeric HTML entity, such
as E<Agrave>
-=back
+Most of the time, you will only need a single set of angle brackets to
+delimit the beginning and end of interior sequences. However, sometimes
+you will want to put a right angle bracket (or greater-than sign '>')
+inside of a sequence. This is particularly common when using a sequence
+to provide a different font-type for a snippet of code. As with all
+things in Perl, there is more than one way to do it. One way is to
+simply escape the closing bracket using an C<E> sequence:
+
+ C<$a E<lt>=E<gt> $b>
+
+This will produce: "C<$a E<lt>=E<gt> $b>"
+
+A more readable, and perhaps more "plain" way is to use an alternate set of
+delimiters that doesn't require a ">" to be escaped. As of perl5.5.660,
+doubled angle brackets ("<<" and ">>") may be used I<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
+trick:
+
+ C<< $a <=> $b >>
+
+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
+'<' of the opening delimiter, and immediately precedes the first '>' of
+the closing delimiter. So the following will also work:
+
+ C<<< $a <=> $b >>>
+ C<<<< $a <=> $b >>>>
+
+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.
+
+
+=head2 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
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 B<pod2man> (that's for nroff(1) and troff(1)),
-B<pod2html>, B<pod2latex>, and B<pod2fm>.
+B<pod2
text>, B<pod2html>, B<pod2latex>, and B<pod2fm>.
-=head1 Embedding Pods in Perl Modules
+=head2 Embedding Pods in Perl Modules
You can embed pod documentation in your Perl scripts. Start your
-documentation with a =head1 command at the beg, and end it with
-an =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 a blank line there before
-the first pod directive.
+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__
modern - I am a modern module
-If you had not had that blank line there, then the translators wouldn't
+If you had not had that empty line there, then the translators wouldn't
have seen it.
-=head1 Common Pod Pitfalls
+=head2 Common Pod Pitfalls
=over 4
=item *
Pod translators usually will require paragraphs to be separated by
-completely empty lines. If you have an apparently blank line with
+completely empty lines. If you have an apparently empty line with
some spaces on it, this can cause odd formatting.
=item *
LE<lt>fooE<gt> manpage>, 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 LE<lt>show this text|fooE<gt> instead.
+
=item *
-The script F<pod/checkpods.PL> in the Perl source distribution
-provides skeletal checking for lines that look blank but aren't
-B<only>, but is there as a placeholder until someone writes
-Pod::Checker. The best way to check your pod is to pass it through
+The B<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.
=head1 SEE ALSO
-L<pod2man> and L<perlsyn/"PODs: Embedded Documentation">
+L<pod2man>, L<perlsyn/"PODs: Embedded Documentation">,
+L<podchecker>
=head1 AUTHOR
https://perl5.git.perl.org / perl5.git / blobdiff