Pod::Abstract(3) User Contributed Perl Documentation Pod::Abstract(3)NAMEPod::Abstract - Abstract document tree for Perl POD documents
SYNOPSIS
use Pod::Abstract;
use Pod::Abstract::BuildNode qw(node);
# Get all the first level headings, and put them in a verbatim block
# at the start of the document
my $pa = Pod::Abstract->load_filehandle(\*STDIN);
my @headings = $pa->select('/head1@heading');
my @headings_text = map { $_->pod } @headings;
my $headings_node = node->verbatim(join "\n",@headings_text);
$pa->unshift( node->cut );
$pa->unshift( $headings_node );
$pa->unshift( node->pod );
print $pa->pod;
DESCRIPTION
POD::Abstract provides a means to load a POD (or POD compatible)
document without direct reference to it's syntax, and perform
manipulations on the abstract syntax tree.
This can be used to support additional features for POD, to format
output, to compile into alternative formats, etc.
WHY?
If you've ever asked yourself "What does Pod do for me?", this module
is intended to answer that question.
While Pod looks like a simple format, the specification calls for a
number of special cases to be handled, and that makes any software that
works on Pod as text more complex than it needs to be.
In addition to this, Pod does not lend itself to a natural structured
model. This makes it difficult to manipulate without damaging the
validity of the document.
Pod::Abstract solves these problems by loading the document into a
structured tree, and providing consistent traversal, searching,
manpulation and re-serialisation. Pod related utilities are easy to
write using Pod::Abstract.
The design goal of Pod::Abstract is to do the hard work for the
programmer - the library should work for you, and as such it should be
significantly easier than string mashing what you want out of a Pod
document.
PROCESSING MODEL
The intent with POD::Abstract is to provide a means to decorate a parse
tree, rather than manipulate text, to allow other software to add
features and functionality to POD based documenation systems.
If you wish to write modules that interact nicely with other
POD::Abstract modules, then you should provide a POD::Abstract ->
POD::Abstract translation. Leave any document element that your program
is not interested in directly untouched in the parse tree, and if you
have data that could be useful to other packages, decorate the parse
tree with that data even if you don't see any direct way to use it in
the output.
In this way, when you want one more feature for POD, rather than write
or fork a whole translator, a single inline "decorator" can be added.
The "paf" utility provides a good starting point, which also allows you
to hook in to an existing filter/transform library. Simply add a
"Pod::Abstract::Filter" class to the namespace and it should start
working as a "paf" command.
EXAMPLE
Suppose you are frustrated by the verbose list syntax used by regular
POD. You might reasonably want to define a simplified list format for
your own use, except POD formatters won't support it.
With Pod::Abstract you can write an inline filter to convert:
* item 1
* item 2
* item 3
into:
=over
=item *
item 1
=item *
item 2
=item *
item 3
=back
This transformation can be simply performed on the document tree. If
your formatter does not use Pod::Abstract, you can simply pipe out POD
and use a regular formatter. If your formatter supports Pod::Abstract
though, then you can feed in the syntax tree directly without having to
re-serialise and parse the document.
In addition to this, because the source document is still valid Pod,
you aren't breaking compatibility with regular perldoc just by making
Pod::Abstract transformations.
POD SUPPORT
Pod::Abstract aims to support all POD rules defined in perlpodspec
(even the ones I don't like), except for those directly related to
formatting output, or which cannot be implemented generically.
COMPONENTSPod::Abstract is comprised of:
· The parser, which loads a document tree for you.
You should access this through "Pod::Abstract", not directly
· The document tree, which is the root node you are given by the
parser. Calling pod on the root node should always give you back
your original document.
See Pod::Abstract::Node
· Pod::Abstract::Path, the node selection expression language. This
is generally called by doing "$node->select(PATH_EXP)".
Pod::Abstract::Path is the most complex and powerful component of
this module, and if you're not using it you should be. ;)
This allows you to ask questions like:
"In the first head1 that starts with "A", find me the head2
matching 'foo' with bold text somewhere in the preceding paragraph
or heading"
/head1[@heading=~{^A}](0)/head2[@heading=~{foo}i]<<head2 :paragraph[//:B]
You probably don't need anything that complex, but it's there if
you do.
· The node builder, Pod::Abstract::BuildNode
METHODS
load_file
my $pa = Pod::Abstract->load_file( FILENAME );
Read the POD document in the named file. Returns the root node of the
document.
load_filehandle
my $pa = Pod::Abstract->load_file( FH );
Load a POD document from the provided filehandle reference. Returns the
root node of the document.
load_string
my $pa = Pod::Abstract->load_string( STRING );
Loads a POD document from a scalar string value. Returns the root node
of the document.
AUTHOR
Ben Lilburne <bnej@mac.com>
COPYRIGHT AND LICENSE
Copyright (C) 2009 Ben Lilburne
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.14.1 2010-01-03 Pod::Abstract(3)
