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<chapter id="raptor-parsers">
<title>Parsers in Raptor (syntax to triples)</title>

<section id="raptor-parsers-intro">
<title>Introduction</title>

<para>This section describes the parsers that can be compiled into
Raptor and their features.  The exact parsers supported may vary
by different builds of raptor and can be queried at run-time by
use of the 
<link linkend="raptor-parsers-enumerate"><function>raptor_parsers_enumerate</function></link>
and
<link linkend="raptor-syntaxes-enumerate"><function>raptor_syntaxes_enumerate</function></link>
functions</para>

<para>The optional features that may be set on parsers can also
be queried at run-time iwth the 
<link linkend="raptor-features-enumerate"><function>raptor_features_enumerate</function></link>
function.</para>

</section>


<section id="parser-grddl">
<title>GRDDL over XHTML/XML using XSLT parser (name <literal>grddl</literal>)</title>
<para>A parser for
<ulink url="http://www.w3.org/2004/01/rdxh/spec">Gleaning Resource Descriptions from Dialects of Languages (GRDDL)</ulink>
which allows reading XHTML and XML as RDF triples by using
profiles in the document that declare XSLT transforms from the XHTML/XML
content into RDF/XML which is the RDF content.</para>

<para>The parser does not support all the GRDDL styles, for example
<literal>dataview:namespaceTransformation</literal>, or perform recursive
transformations.</para>

</section>


<section id="parser-guess">
<title>Guess parser (name <literal>guess</literal>)</title>
<para>
This is a special parser that picks the actual parser to use based
on the content type, the content bytes or the content identifier.  The
content name can be either from a local file or from a URI.
</para>

<para>If the protocol that delivered the content (such as HTTP)
provided a <emphasis>Content Type</emphasis> (aka MIME Type) then
this will be the primary means for identifying th ecotnent.
</para>

<para>The secondary means to identify the content are the bytes of
the content (if available), otherwise the content identifier is used,
which is the least reliable.
</para>

</section>


<section id="parser-ntriples">
<title>N-Triples parser (name <literal>ntriples</literal>)</title>

<para>A parser for the
<ulink url="http://www.w3.org/TR/rdf-testcases/#ntriples">N-Triples</ulink>
syntax as used by the 
<ulink url="http://www.w3.org/2001/sw/RDFCore/">W3C RDF Core working group</ulink>
for the <ulink url="http://www.w3.org/TR/rdf-testcases/">RDF Test Cases</ulink>.
</para>

</section>


<section id="parser-rdfxml">
<title>RDF/XML parser - default (name <literal>rdfxml</literal>)</title>
<para>
A parser for the standard
<ulink url="http://www.w3.org/TR/rdf-syntax-grammar/">RDF/XML syntax</ulink>
as revised by the
<ulink url="http://www.w3.org/2001/sw/RDFCore/">W3C RDF Core working group</ulink>.</para>

<para>This is the default parser in Raptor.</para>

<para>Features of this parser:</para>
<itemizedlist>
<listitem><para>Fully handles the <ulink url="http://www.w3.org/TR/rdf-syntax-grammar/">RDF/XML syntax updates</ulink> for <ulink url="http://www.w3.org/TR/xmlbase/">XML Base</ulink>, <literal>xml:lang</literal>, RDF datatyping and Collections.</para></listitem>

<listitem><para>Handles all RDF vocabularies such as <ulink url="http://www.foaf-project.org/">FOAF</ulink>, <ulink url="http://www.purl.org/rss/1.0/">RSS 1.0</ulink>, <ulink url="http://dublincore.org/">Dublin Core</ulink>, <ulink url="http://www.w3.org/TR/owl-features/">OWL</ulink>, <ulink url="http://usefulinc.com/doap">DOAP</ulink></para></listitem>

<listitem><para>Handles <literal>rdf:resource</literal> / <literal>resource</literal> attributes</para></listitem>

<listitem><para>Uses <ulink url="http://expat.sourceforge.net/">expat</ulink> and/or (GNOME) <ulink url="http://xmlsoft.org/">libxml</ulink> XML parsers as available or required</para></listitem>

</itemizedlist>

</section>


<section id="parser-rss-tag-soup">
<title>RSS Tag Soup parser (name <literal>rss-tag-soup</literal>)</title>

<para>A parser for the multiple XML RSS formats that use the elements
such as <literal>channel</literal>, <literal>item</literal>,
<literal>title</literal>, <literal>description</literal>
in different ways.
This includes support for the Atom 1.0 syndication format defined in IETF
<ulink url="http://www.ietf.org/rfc/rfc4287.txt">RFC 4287</ulink>
</para>

<para>The parser attempts to turn the input into
<ulink url="http://www.purl.org/rss/1.0/">RSS 1.0</ulink>
RDF triples in the RSS 1.0 model of a syndication feed.
This includes triples for RSS Enclosures.
</para>

<para>
True <ulink url="http://www.purl.org/rss/1.0/">RSS 1.0</ulink> when
wanted to be used as a full RDF vocabulary, is best parsed by the
RDF/XML parser (name <literal>rdfxml</literal>).
</para>


</section>


<section id="parser-turtle">
<title>Turtle Terse RDF Triple Language parser (name <literal>turtle</literal>)</title>

<para>A parser for the
<ulink url="http://www.dajobe.org/2004/01/turtle/">Turtle Terse RDF Triple Language</ulink>
syntax, designed as a useful subset of
<ulink url="http://www.w3.org/DesignIssues/Notation3">Notation 3</ulink>.
</para>

</section>


</chapter>

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