Perl 6 Pod

An easy-to-use markup language

Pod is an easy-to-use markup language. Pod can be used for writing language documentation, for documenting programs and modules, as well as for other types of document composition.

Every Pod document has to begin with =begin pod and end with =end pod. Everything between these 2 delimiters will be processed and used to generate documentation.

=begin pod
 
A very simple Perl 6 Pod document
 
=end pod

Block Structure

A Pod document may consist of multiple Pod blocks. There are three ways to define a block; all of which yield the same result. You can use whichever form is most convenient for your particular documentation task.

Delimited blocks

Delimited blocks are bound by =begin and =end markers, both of which are followed by the typename of the block.

=begin head1
Top Level Heading
=end head1

Paragraph blocks

Paragraph blocks begin by a =for marker and end by the next Pod directive or the first blank line. The =for marker is followed by the typename of the block.

=for head1
Top Level Heading

Abbreviated blocks

Abbreviated blocks begin by an '=' sign, which is followed immediately by the typename of the block. The block ends at the next Pod directive or the first blank line.

=head1 Top Level Heading 

Block types

Pod offers a wide range of standard block types.

Headings

Headings can be defined using =headN, where N is greater than zero (e.g., =head1, =head2, …).

=head1 A Top Level Heading 
 
=head2 A Second Level Heading 
 
=head3 A Third Level Heading 

Ordinary paragraphs

Ordinary paragraph consist of text that is to be formatted into a document at the current level of nesting, with whitespace squeezed, lines filled, and any special inline mark-up applied.

Ordinary paragraphs consist of one or more consecutive lines of text, each of which starts with a non-whitespace character. The paragraph is terminated by the first blank line or block directive.

For example:

=head1 This is a heading block 
 
This is an ordinary paragraph.
Its text  will   be     squeezed     and
short lines filled. It is terminated by
the first blank line.
 
This is another ordinary paragraph.
Its     text    will  also be squeezed and
short lines filled. It is terminated by
the trailing directive on the next line.
 
=head2 This is another heading block 
 
This is yet another ordinary paragraph,
at the first virtual column set by the
previous directive

Ordinary paragraphs do not require an explicit marker or delimiters.

Alternatively, there is also an explicit =para marker that can be used to explicitly mark a paragraph.

=para
This is an ordinary paragraph.
Its text  will   be     squeezed     and
short lines filled.

In addition, the longer =begin para and =end para form can be used.

For example:

=begin para
This is an ordinary paragraph.
Its text  will   be     squeezed     and
short lines filled.
 
This is still part of the same paragraph,
which continues until an...
=end para

As demonstrated by the previous example, within a delimited =begin para and =end para block, any blank lines are preserved.

Code blocks

Code blocks are used to specify source code, which should be rendered without re-justification, without whitespace-squeezing, and without recognizing any inline formatting codes. Typically these blocks are used to show examples of code, mark-up, or other textual specifications, and are rendered using a fixed-width font.

A code block may be implicitly specified as one or more lines of text, each of which starts with a whitespace character. The implicit code block is then terminated by a blank line.

For example:

This ordinary paragraph introduces a code block:
 
    my $name = 'John Doe';
    say $name;

Code blocks can also be explicitly defined by enclosing them in =begin code and =end code

    =begin code
    my $name = 'John Doe';
    say $name;
    =end code

I/O blocks

Pod provides blocks for specifying the input and output of programs.

The =input block is used to specify pre-formatted keyboard input, which should be rendered without re-justification or squeezing of whitespace.

The =output block is used to specify pre-formatted terminal or file output, which should also be rendered without re-justification or whitespace-squeezing.

Lists

Unordered Lists

Lists in Pod are specified as a series of =item blocks.

For example:

The three suspects are:
 
=item  Happy 
=item  Sleepy 
=item  Grumpy 

The three suspects are:

Multi-level Lists

Lists may be multi-level, with items at each level specified using the =item1, =item2, =item3, etc. blocks.

Note that =item is just an abbreviation for =item1.

For example:

=item1  Animal 
=item2     Vertebrate 
=item2     Invertebrate 
 
=item1  Phase 
=item2     Solid 
=item2     Liquid 
=item2     Gas 

Multi-paragraph Lists

Using the delimited form of the =item block (=begin item and =end item), we can specify items that contain multiple paragraphs.

For example:

Let's consider two common proverbs:
 
=begin item
I<The rain in Spain falls mainly on the plain.>
 
This is a common myth and an unconscionable slur on the Spanish
people, the majority of whom are extremely attractive.
=end item
 
=begin item
I<The early bird gets the worm.>
 
In deciding whether to become an early riser, it is worth
considering whether you would actually enjoy annelids
for breakfast.
=end item
 
As you can seefolk wisdom is often of dubious value.

Let's consider two common proverbs:

As you can see, folk wisdom is often of dubious value.

Tables

Check out this page for documentation related to Tables

Pod comments

Pod comments are comments that Pod renderers ignore.

Comments are useful for meta-documentation (documenting the documentation):

=comment Add more here about the algorithm 

Semantic blocks

All uppercase block typenames are reserved for specifying standard documentation, publishing, source components, or meta-information.

=NAME
=AUTHOR
=VERSION
=TITLE
=SUBTITLE

Formatting Codes

Formatting codes provide a way to add inline mark-up to a piece of text.

All Pod formatting codes consist of a single capital letter followed immediately by a set of angle brackets.

Formatting codes may nest other formatting codes.

Bold

To format a text in bold enclose it in B< >

Perl 6 is B<awesome>

Perl 6 is awesome

Italic

To format a text in italic enclose it in I< >

Perl 6 is I<awesome>

Perl 6 is awesome

Underlined

To underline a text enclose it in U< >

Perl 6 is U<awesome>

Code

To flag text as Code and treat it verbatim enclose it in C< >

C<my $var = 1; say $var;>

my $var = 1; say $var;

To create a link enclose it in L< >

Perl 6 homepage L<https://perl6.org>

Perl 6 homepage https://perl6.org

Comments

A comment is text that is never rendered.

To create a comment enclose it in Z< >

Perl 6 is awesome Z<Of course it is!>

Perl 6 is awesome

Notes

Notes are rendered as footnotes.

To create a note enclose it in N< >

Perl 6 is multi-paradigmatic N<Supporting Procedural, Object Oriented, and Functional programming>

Keyboard input

To flag text as keyboard input enclose it in K< >

Enter your name K<John Doe>

Terminal Output

To flag text as terminal output enclose it in T< >

Hello T<John Doe>

Unicode

To include Unicode code points or HTML5 character references in a Pod document, enclose them in E< >

E< > can enclose a number, that number is treated as the decimal Unicode value for the desired code point. It can also enclose explicit binary, octal, decimal, or hexadecimal numbers using the Perl 6 notations for explicitly based numbers.

Perl 6 makes considerable use of the E<171> and E<187> characters.
 
Perl 6 makes considerable use of the E<laquo> and E<raquo> characters.
 
Perl 6 makes considerable use of the E<0b10101011> and E<0b10111011> characters.
 
Perl 6 makes considerable use of the E<0o253> and E<0o273> characters.
 
Perl 6 makes considerable use of the E<0d171> and E<0d187> characters.
 
Perl 6 makes considerable use of the E<0xAB> and E<0xBB> characters.

Perl 6 makes considerable use of the « and » characters.

Rendering Pod

HTML

In order to generate HTML from Pod, you need the Pod::To::HTML module.

If it is not already installed, install it by running the following command: zef install Pod::To::HTML

Using the terminal run the following command:

perl6 --doc=HTML input.pod6 > output.html

Markdown

In order to generate Markdown from Pod, you need the Pod::To::Markdown module.

If it is not already installed, install it by running the following command: zef install Pod::To::Markdown

Using the terminal run the following command:

perl6 --doc=Markdown input.pod6 > output.md

Text

In order to generate Text from Pod, you can use the default Pod::To::Text module.

Using the terminal, run the following command:

perl6 --doc input.pod6 > output.txt

You can even embed Pod directly in your program and add the traditional Unix command line "--man" option to your program with a multi MAIN subroutine like this:

multi MAIN(Bool :$man)
{
    run $*EXECUTABLE'--doc'$*PROGRAM;
}

Now myprogram --man will output your Pod rendered as a man page.