mirror of
https://github.com/cookiengineer/audacity
synced 2025-06-17 16:40:07 +02:00
154 lines
7.4 KiB
HTML
154 lines
7.4 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
||
<html>
|
||
<head>
|
||
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
|
||
<title>Get or construct RDF Triples</title>
|
||
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2">
|
||
<link rel="start" href="index.html" title="Raptor RDF Syntax Parsing and Serializing Library Manual">
|
||
<link rel="up" href="tutorial-serializing.html" title="Serializing RDF triples to a syntax">
|
||
<link rel="prev" href="tutorial-serializer-to-destination.html" title="Provide a destination for the serialized syntax">
|
||
<link rel="next" href="tutorial-serializer-send-triples.html" title="Send RDF Triples to serializer">
|
||
<meta name="generator" content="GTK-Doc V1.10 (XML mode)">
|
||
<link rel="stylesheet" href="style.css" type="text/css">
|
||
<link rel="chapter" href="introduction.html" title="Raptor Overview">
|
||
<link rel="part" href="tutorial.html" title="Part I. Raptor Tutorial">
|
||
<link rel="chapter" href="tutorial-initialising-finishing.html" title="Initialising and Finishing using the Library">
|
||
<link rel="chapter" href="tutorial-querying-functionality.html" title="Listing built-in functionality">
|
||
<link rel="chapter" href="tutorial-parsing.html" title="Parsing syntaxes to RDF Triples">
|
||
<link rel="chapter" href="tutorial-serializing.html" title="Serializing RDF triples to a syntax">
|
||
<link rel="part" href="reference-manual.html" title="Part II. Raptor Reference Manual">
|
||
<link rel="chapter" href="raptor-parsers.html" title="Parsers in Raptor (syntax to triples)">
|
||
<link rel="chapter" href="raptor-serializers.html" title="Serializers in Raptor (triples to syntax)">
|
||
<link rel="index" href="ix01.html" title="Index">
|
||
</head>
|
||
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
|
||
<table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2"><tr valign="middle">
|
||
<td><a accesskey="p" href="tutorial-serializer-to-destination.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td>
|
||
<td><a accesskey="u" href="tutorial-serializing.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td>
|
||
<td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td>
|
||
<th width="100%" align="center">Raptor RDF Syntax Parsing and Serializing Library Manual</th>
|
||
<td><a accesskey="n" href="tutorial-serializer-send-triples.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
|
||
</tr></table>
|
||
<div class="section" lang="en">
|
||
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
|
||
<a name="tutorial-serializer-get-triples"></a>Get or construct RDF Triples</h2></div></div></div>
|
||
<p>
|
||
An <a class="link" href="raptor-section-triples.html#raptor-statement" title="raptor_statement"><span class="type">raptor_statement</span></a>
|
||
can be made either by receiving them from a
|
||
<a class="link" href="raptor-section-parser.html#raptor-parser" title="raptor_parser"><span class="type">raptor_parser</span></a>
|
||
via parsing or can be constructed by hand.</p>
|
||
<p>When constructing by hand,
|
||
the <a class="link" href="raptor-section-triples.html#raptor-statement" title="raptor_statement"><span class="type">raptor_statement</span></a>
|
||
structure should be allocated by the application and the fields
|
||
filled in. Each triple has three parts. The subject can be a URI
|
||
or blank node, the predicate can only be a URI and the object
|
||
can be a URI, blank node or RDF literal. RDF literals can have either
|
||
just a Unicode string, a Unicode string and a language or a Unicode
|
||
string and a datatype URI.</p>
|
||
<p>The triple part types are set as fields named
|
||
like <code class="literal">subject_type</code> for describing
|
||
field <code class="literal">subject</code>.
|
||
So to initialise the subject of the triple,
|
||
set the field <code class="literal">statement.subject</code> to point to a
|
||
previously allocated
|
||
<a class="link" href="raptor-section-uri.html#raptor-uri" title="raptor_uri"><span class="type">raptor_uri*</span></a> object (for URI)
|
||
or <code class="literal">char*</code> (for blank node) and
|
||
set <code class="literal">statement.subject_type</code>
|
||
to <code class="literal">RAPTOR_IDENTIFIER_TYPE_RESOURCE</code> or
|
||
<code class="literal">RAPTOR_IDENTIFIER_TYPE_ANONYMOUS</code> respectively.
|
||
Triple predicates are always of type
|
||
<code class="literal">RAPTOR_IDENTIFIER_TYPE_RESOURCE</code>.
|
||
Triple objects are all all types given above and also
|
||
<code class="literal">RAPTOR_IDENTIFIER_TYPE_LITERAL</code> which takes
|
||
an <code class="literal">unsigned char*</code> pointer plus an optional
|
||
language <code class="literal">char*</code> pointer
|
||
in the <code class="literal">object_literal_language</code> field OR a
|
||
a <code class="literal">raptor_uri*</code> literal datatype pointer
|
||
in the <code class="literal">object_literal_datatype</code> field.
|
||
The triple part types are described under
|
||
<a class="link" href="raptor-section-triples.html#raptor-identifier-type" title="enum raptor_identifier_type"><span class="type">raptor_identifier_type</span>.</a>
|
||
</p>
|
||
<div class="example">
|
||
<a name="raptor-example-rdfserialize"></a><p class="title"><b>Example 3. <code class="filename">rdfserialize.c</code>: Serialize 1 triple to RDF/XML (Abbreviated)</b></p>
|
||
<div class="example-contents">
|
||
<pre class="programlisting">
|
||
#include <stdio.h>
|
||
#include <raptor.h>
|
||
#include <stdlib.h>
|
||
|
||
/* rdfserialize.c: serialize 1 triple to RDF/XML-Abbrev */
|
||
|
||
int
|
||
main(int argc, char *argv[])
|
||
{
|
||
raptor_serializer* rdf_serializer=NULL;
|
||
unsigned char *uri_string;
|
||
raptor_uri *base_uri;
|
||
raptor_statement* triple;
|
||
|
||
raptor_init();
|
||
|
||
uri_string=raptor_uri_filename_to_uri_string(argv[1]);
|
||
base_uri=raptor_new_uri(uri_string);
|
||
|
||
rdf_serializer=raptor_new_serializer("rdfxml-abbrev");
|
||
raptor_serialize_start_to_file_handle(rdf_serializer, base_uri, stdout);
|
||
|
||
/* Make a triple with URI subject, URI predicate, literal object */
|
||
triple=malloc(sizeof(raptor_statement));
|
||
triple->subject=(void*)raptor_new_uri((const unsigned char*)"http://example.org/subject");
|
||
triple->subject_type=RAPTOR_IDENTIFIER_TYPE_RESOURCE;
|
||
triple->predicate=(void*)raptor_new_uri((const unsigned char*)"http://example.org/predicate");
|
||
triple->predicate_type=RAPTOR_IDENTIFIER_TYPE_RESOURCE;
|
||
triple->object="An example literal";
|
||
triple->object_type=RAPTOR_IDENTIFIER_TYPE_LITERAL;
|
||
triple->object_literal_language=(const unsigned char*)"en";
|
||
|
||
/* Write the triple */
|
||
raptor_serialize_statement(rdf_serializer, triple);
|
||
|
||
/* Delete the triple */
|
||
raptor_free_uri((raptor_uri*)triple->subject);
|
||
raptor_free_uri((raptor_uri*)triple->predicate);
|
||
free(triple);
|
||
|
||
raptor_serialize_end(rdf_serializer);
|
||
raptor_free_serializer(rdf_serializer);
|
||
|
||
raptor_free_uri(base_uri);
|
||
raptor_free_memory(uri_string);
|
||
|
||
raptor_finish();
|
||
return 0;
|
||
}
|
||
|
||
</pre>
|
||
<p>Compile it like this:
|
||
</p>
|
||
<pre class="screen">
|
||
$ gcc -o rdfserialize rdfserialize.c `raptor-config --cflags` `raptor-config --libs`
|
||
</pre>
|
||
<p>
|
||
and run it with an optional base URI argument
|
||
</p>
|
||
<pre class="screen">
|
||
$ ./rdfserialize
|
||
<?xml version="1.0" encoding="utf-8"?>
|
||
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
|
||
<rdf:Description rdf:about="http://example.org/subject">
|
||
<ns0:predicate xmlns:ns0="http://example.org/" xml:lang="en">An example</ns0:predicate>
|
||
</rdf:Description>
|
||
</rdf:RDF>
|
||
</pre>
|
||
<p>
|
||
</p>
|
||
</div>
|
||
</div>
|
||
<br class="example-break">
|
||
</div>
|
||
<div class="footer">
|
||
<hr>
|
||
Generated by GTK-Doc V1.10</div>
|
||
</body>
|
||
</html>
|