NAME

HTML::HTML5::Outline - implementation of the HTML5 Outline algorithm

SYNOPSIS

        use JSON;
        use HTML::HTML5::Outline;
        
        my $html = <<'HTML';
        <!doctype html>
        <h1>Hello</h1>
        <h2>World</h2>
        <h1>Good Morning</h1>
        <h2>Vietnam</h2>
        HTML
        
        my $outline = HTML::HTML5::Outline->new($html);
        print to_json($outline->to_hashref, {pretty=>1,canonical=>1});

DESCRIPTION

This is an implementation of the HTML5 Outline algorithm, as per http://www.w3.org/TR/html5/sections.html#outlines.

The module can output a JSON-friendly hashref, or an RDF model.

Constructor

HTML::HTML5::Outline->new($html, %options)
Construct a new outline. $html is the HTML to generate an outline from, either as an HTML or XHTML string, or as an XML::LibXML::Document object.

Options:
- default_language - default language to assume text is in when no lang/xml:lang attribute is available. e.g. 'en-gb'.
- element_subjects - rather advanced feature that doesn't bear explaining. See USE WITH RDF::RDFA::PARSER for an example.
- microformats - support <ul class="xoxo">, <ol class="xoxo"> and <whatever class="figure"> as sectioning elements (like <section>, <figure>, etc). Boolean, defaults to false.
- parser - 'html' (default) or 'xml' - choose the parser to use for XHTML/HTML. If the constructor is passed an XML::LibXML::Document, this is ignored.
- suppress_collections - allows rdf:List stuff to be suppressed from RDF output. RDF output - especially in Turtle format - looks somewhat nicer without them, but if you care about the order of headings and sections, then you'll want them. Boolean, defaults to false.
- uri - the document URI for resolving relative URI references. Only really used by the RDF output.

Object Methods

to_hashref
Returns data as a nested hashref/arrayref structure. Dump it as JSON and you'll figure out the format pretty easily.
to_rdf
Returns data as a n RDF::Trine::Model. Requires RDF::Trine to be installed. Otherwise this method won't exist.
primary_outlinee
Returns a HTML::HTML5::Outline::Outlinee element representing the outline for the page.

Class Methods

has_rdf
Indicates whether the to_rdf object method exists.

USE WITH RDF::RDFA::PARSER

This module produces RDF data where many of the resources described are HTML elements. RDFa data typically does not, but RDF::RDFa::Parser does also support some extensions to RDFa which do (e.g. support for the cite and role attributes). It's useful to combine the RDF data from each, and RDF::RDFa::Parser 1.093 and upwards contains a few shims to make this possible.

Without further ado...

        use HTML::HTML5::Outline;
        use RDF::RDFa::Parser 1.093;
        use RDF::TrineShortcuts;

        my $rdfa = RDF::RDFa::Parser->new(
                $html_source,
                $base_url,
                RDF::RDFa::Parser::Config->new(
                        'html5', '1.1',
                        role_attr     => 1,
                        cite_attr     => 1,
                        longdesc_attr => 1,
                        ),
                )->consume;
        
        my $outline = HTML::HTML5::Outline->new(
                $rdfa->dom,
                uri              => $rdfa->uri,
                element_subjects => $rdfa->element_subjects,
                );
        
        # Merging two graphs is pretty complicated in RDF::Trine
        # but a little easier with RDF::TrineShortcuts...
        my $combined = rdf_parse();
        rdf_parse($rdfa->graph,     model => $combined);
        rdf_parse($outline->to_rdf, model => $combined);
        
        my $NS = {
                dc    => 'http://purl.org/dc/terms/',
                o     => 'http://ontologi.es/outline#',
                type  => 'http://purl.org/dc/dcmitype/',
                xs    => 'http://www.w3.org/2001/XMLSchema#',
                xhv   => 'http://www.w3.org/1999/xhtml/vocab#',
                };
        
        print rdf_string($combined => 'Turtle', namespaces => $NS);

AUTHOR

Toby Inkster, <tobyink@cpan.org>

ACKNOWLEDGEMENTS

This module is a fork of the document structure parser from Swignition <http://buzzword.org.uk/swignition/>.

That in turn includes the following credits: thanks to Ryan King and Geoffrey Sneddon for pointing me towards [the HTML5] algorithm. I also used Geoffrey's python implementation as a crib sheet to help me figure out what was supposed to happen when the HTML5 spec was ambiguous.

COPYRIGHT AND LICENCE

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

CPAN RT