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// $Id: RDF.pike,v 1.1.1.1 2006/03/27 12:40:11 exodusd Exp $
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// import Locale.Language;
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//! Represents an RDF domain which can contain any number of complete
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constant rdf_ns = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";
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// These should be in some generic namespace module. Perhaps.
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constant default_ns = ([
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"http://www.w3.org/2002/07/owl#" : "owl",
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"http://www.w3.org/2000/01/rdf-schema#" : "rdfs",
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"http://www.w3.org/2001/XMLSchema#" : "xsd",
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static int(1..) node_counter = 1;
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static mapping(string:Resource) uris = ([]);
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// Returns ({ namespace, object })
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static array(string) uri_parts(string uri) {
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if(sscanf(uri, "%s#%s", ns,obj)==2)
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return ({ ns+"#", obj });
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if(sscanf(reverse(uri), "%s/%s", obj,ns)==2) {
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if(reverse(ns)=="http:/")
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return ({ 0, "http://"+reverse(obj) });
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return ({ reverse(ns)+"/", reverse(obj) });
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//! Instances of this class represents resources as defined in RDF:
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//! All things being described by RDF expressions are called resources. A
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//! resource may be an entire Web page; such as the HTML document
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//! "http://www.w3.org/Overview.html" for example. A resource may be a
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//! part of a Web page; e.g. a specific HTML or XML element within the
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//! document source. A resource may also be a whole collection of pages;
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//! e.g. an entire Web site. A resource may also be an object that is
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//! not directly accessible via the Web; e.g. a printed book.
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//! This general resource is anonymous and has no URI or literal id.
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//! Resources instantiated from this class should not be used in
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//! other RDF domain objects.
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//! @[URIResource], @[LiteralResource]
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static int(1..) number;
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constant is_resource = 1;
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static void create() {
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number = node_counter++;
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//! Returns the nodes' N-triple serialized ID.
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string get_n_triple_name() {
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return "_:Resource"+number;
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//! Returns the nodes' 3-tuple serialized ID.
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string get_3_tuple_name() {
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return "RDF:_"+number;
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static string __sprintf(string c, int t) {
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if(t=='t') return "RDF."+c;
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if(t=='O') return "RDF."+c+"(" + get_n_triple_name() + ")";
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string _sprintf(int t) { return __sprintf("Resource", t); }
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static int __hash() { return number; }
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//! Resource identified by literal.
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class LiteralResource {
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constant is_literal_resource = 1;
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//! Used to contain rdf:datatype value.
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//! The resource will be identified by @[literal].
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static void create(string literal) {
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string get_n_triple_name() {
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string ret = "\"" + encode_n_triple_string(id) + "\"";
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if(datatype) ret += "^^<" + datatype + ">";
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string get_3_tuple_name() {
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return get_n_triple_name();
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//! Returns the literal as an XML string.
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return id; // FIXME: XML quote.
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//! Returns the literal string.
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string get_literal() {
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int(0..1) _equal(mixed r) {
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if(!objectp(r) || !r->is_literal_resource) return 0;
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string _sprintf(int t) { return __sprintf("LiteralResource", t); }
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//! Resource identified by URI.
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constant is_uri_resource = 1;
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//! Creates an URI resource with the @[uri] as identifier.
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//! Throws an error if another resource with the
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//! same URI already exists in the RDF domain.
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static void create(string uri) {
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error("A resource with URI %s already exists in the RDF domain.\n", uri);
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//! Returns the URI the resource references to.
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//! Returns the qualifying name, or zero.
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string get_qname(void|string ns) {
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if(!ns) ns=common_ns;
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[ nns, obj ] = uri_parts(id);
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if(!obj) error("Could not produce qname.\n");
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if(!nns || nns==ns) return obj;
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return namespaces[nns]+":"+obj;
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//! Returns the namespace this resource URI references to.
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string get_namespace() {
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return uri_parts(id)[0];
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string get_n_triple_name() {
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return "<" + id + ">";
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string get_3_tuple_name() {
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return "[" + id + "]";
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int(0..1) _equal(mixed r) {
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if(!objectp(r) || !r->is_uri_resource) return 0;
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string _sprintf(int t) { return __sprintf("URIResource", t); }
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//! Resource used for RDF-technical reasons like reification.
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//! The resource will be identified by the identifier @[rdf_id]
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static void create(string rdf_id) {
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::create(rdf_ns + rdf_id);
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//! Returns the qualifying name.
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string get_qname(void|string ns) {
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if(!ns) ns = common_ns;
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sscanf(id, rdf_ns+"%s", rid);
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if(ns==rdf_ns) return rid;
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RDFResource rdf_Statement = RDFResource("Statement"); //! Statement resource.
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RDFResource rdf_predicate = RDFResource("predicate"); //! predicate resource.
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RDFResource rdf_subject = RDFResource("subject"); //! subject resource.
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RDFResource rdf_object = RDFResource("object"); //! object resource.
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RDFResource rdf_type = RDFResource("type"); //! type resource.
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RDFResource rdf_Seq = RDFResource("Seq"); //! Seq resource.
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RDFResource rdf_first = RDFResource("first"); //! first resource.
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RDFResource rdf_rest = RDFResource("rest"); //! rest resource.
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RDFResource rdf_nil = RDFResource("nil"); //! nil resource.
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static int(0..1) is_resource(mixed res) {
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if(!objectp(res)) return 0;
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return res->is_resource;
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// General RDF set modification
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// predicate : Relation( subject, object )
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static mapping(Resource:Visconte.SemWeb.BinaryRelation) statements = ([]);
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//! Adds a statement to the RDF set.
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//! Throws an exception if any argument isn't a Resouce object.
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void add_statement(Resource subj, Resource pred, Resource obj) {
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if(!is_resource(subj) || !is_resource(pred) || !is_resource(obj))
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error("Non-resource argument to add_statement");
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Visconte.SemWeb.BinaryRelation rel = statements[pred];
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rel = Visconte.SemWeb.BinaryRelation();
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statements[pred] = rel;
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//! Returns 1 if the RDF domain contains the relation {subj, pred, obj},
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int(0..1) has_statement(Resource subj, Resource pred, Resource obj) {
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Visconte.SemWeb.BinaryRelation rel = statements[pred];
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return rel->contains(subj,obj);
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//! Removes the relation from the RDF set. Returns 1 if the relation
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//! did exist in the RDF set.
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int(0..1) remove_statement(Resource subj, Resource pred, Resource obj) {
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if(!has_statement(subj, pred, obj)) return 0;
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Visconte.SemWeb.BinaryRelation rel = statements[pred];
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rel->contains(subj,obj);
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rel->remove(subj,obj);
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if(!sizeof(statements[pred])) m_delete(statements, pred);
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//! Reifies the statement @tt{{ pred, subj, obj }@} and returns
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//! the resource that denotes the reified statement. There will
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//! not be any check to see if the unreified statement is already
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//! in the domain, making it possible to define the relation twice.
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//! The original statement will not be removed.
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//! The subject of the reified statement.
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Resource reify_low(Resource subj, Resource pred, Resource obj) {
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Resource r = Resource();
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add_statement(r, rdf_predicate, pred);
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add_statement(r, rdf_subject, subj);
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add_statement(r, rdf_object, obj);
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add_statement(r, rdf_type, rdf_Statement);
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//! Returns a resource that is the subject of the reified statement
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//! {subj, pred, obj}, if such a resource exists in the RDF domain.
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Resource get_reify(Resource subj, Resource pred, Resource obj) {
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array rs = find_statements(0, rdf_predicate, pred)[*][0] &
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find_statements(0, rdf_subject, subj)[*][0] &
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find_statements(0, rdf_object, obj)[*][0];
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// Any one of rs is a reified statment of ({ subj, pred, obj }).
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if(sizeof(rs)) return rs[0];
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//! Returns the result of @[get_reify], if any. Otherwise calls
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//! @[reify_low] followed by @[remove_statement] of the provided
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//! statement {subj, pred, obj}.
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//! The subject of the reified statement.
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Resource reify(Resource subj, Resource pred, Resource obj) {
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Resource r = get_reify(subj, pred, obj);
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r = reify_low(subj, pred, obj);
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remove_statement(subj, pred, obj);
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//! Turns the reified statement @[r] into a normal statement, if possible.
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//! 1 for success, 0 for failure.
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int(0..1) dereify(Resource r) {
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if(sizeof(find_statements(0,0,r))) return 0;
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if(sizeof(find_statements(0,r,0))) return 0;
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array statements = find_statements(r,0,0);
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mapping statement = mkmapping( column(statements,1), column(statements,2) );
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if(sizeof(statement)!=4) return 0;
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add_statement( statement[rdf_subject], statement[rdf_predicate],
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statement[rdf_object] );
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foreach( statements, array statement )
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remove_statement(@statement);
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//! Dereifies as many statements as possible. Returns the number of
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//! dereified statements.
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int(0..) dereify_all() {
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int total, dereified=1;
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array rs = find_statements(0, rdf_type, rdf_Statement)[*][0];
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foreach(rs, Resource r)
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dereified = dereify(r);
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//! Returns all properties in the domain, e.g. all resources that
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//! has been used as predicates.
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array(Resource) get_properties() {
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return indices(statements);
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//! Returns a mapping with all the domains subject resources as
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//! indices and a mapping with that subjects predicates and objects
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mapping(Resource:mapping(Resource:array(Resource))) get_subject_map() {
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foreach(statements; Resource pred; Visconte.SemWeb.BinaryRelation rel)
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foreach(rel; Resource subj; Resource obj)
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subs[subj][pred] += ({ obj });
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subs[subj][pred] = ({ obj });
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subs[subj] = ([ pred:({obj}) ]);
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//! Returns an RDF resource with the given URI as identifier,
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URIResource get_resource(string uri) {
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if(uris[uri]) return uris[uri];
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//! Returns an RDF resource with the given URI as identifier,
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//! or if no such resrouce exists, creates it and returns it.
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URIResource make_resource(string uri) {
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return get_resource(uri) || URIResource(uri);
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//! Returns an array with the statements that matches the given
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//! subject @[subj], predicate @[pred] and object @[obj]. Any
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//! and all of the resources may be zero to disregard from matching
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//! that part of the statement, i.e. find_statements(0,0,0) returns
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//! all statements in the domain.
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//! An array with arrays of three elements.
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//! The subject of the statement
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//! The predicate of the statement
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//! The object of the statement
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array(array(Resource)) find_statements(Resource|int(0..0) subj,
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Resource|int(0..0) pred,
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Resource|int(0..0) obj) {
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// Optimize the case when all search predicates are 0.
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if(!subj && !pred && !obj) {
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foreach(statements; Resource pred; Visconte.SemWeb.BinaryRelation rel)
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foreach(rel; Resource subj; Resource obj)
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ret += ({ ({ subj, pred, obj }) });
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array(array(Resource)) find_subj_obj(Resource subj, Resource pred,
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Resource obj, Visconte.SemWeb.BinaryRelation rel) {
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if(rel(subj,obj)) return ({ ({ subj, pred, obj }) });
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foreach(rel; Resource left; Resource right) {
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if(subj && subj!=left) continue;
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if(obj && obj!=right) continue;
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ret += ({ ({ left, pred, right }) });
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return find_subj_obj(subj, pred, obj, statements[pred]);
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if(pred) return ({});
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foreach(statements; Resource pred; Visconte.SemWeb.BinaryRelation rel)
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ret += find_subj_obj(subj, pred, obj, rel);
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//! Returns @expr{1@} if resource @[r] is used as a subject, otherwise
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int(0..1) is_subject(Resource r) {
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return !!sizeof(find_statements(r,0,0));
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//! Returns @expr{1@} if resource @[r] is used as a predicate,
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//! otherwise @expr{0@}.
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int(0..1) is_predicate(Resource r) {
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return !!sizeof(find_statements(0,r,0));
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//! Returns @expr{1@} if resource @[r] is used as an object, otherwise
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int(0..1) is_object(Resource r) {
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return !!sizeof(find_statements(0,0,r));
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//! Returns a 3-tuple serialization of all the statements in
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string get_3_tuples() {
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String.Buffer ret = String.Buffer();
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foreach(statements; Resource n; Visconte.SemWeb.BinaryRelation rel) {
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string rel_name = n->get_3_tuple_name();
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foreach(rel; Resource left; Resource right) {
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ret->add( "{", left->get_3_tuple_name(), ", ", rel_name,
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", ", right->get_3_tuple_name(), "}\n" );
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//! Returns an N-triples serialization of all the statements in
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string get_n_triples() {
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String.Buffer ret = String.Buffer();
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foreach(statements; Resource n; Visconte.SemWeb.BinaryRelation rel) {
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string rel_name = n->get_n_triple_name();
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foreach(rel; Resource left; Resource right)
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ret->add( left->get_n_triple_name(), " ", rel_name,
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" ", right->get_n_triple_name(), " .\n" );
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//! Parses an N-triples string and adds the found statements
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//! to the RDF set. Returns the number of added relations.
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//! The parser will throw errors on invalid N-triple input.
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int parse_n_triples(string in) {
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class Temp(string id) {
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string _sprintf(int t) { return t=='O' && sprintf("%s(%O)", type, id); }
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constant type = "TempURI";
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constant type = "TempNode";
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constant type = "TempLiteral";
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array(string|Temp) tokens = ({});
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while(pos<sizeof(in)) {
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// Well, we are breaking the BNF, but so is w3c in
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// their examples in the RDF primer.
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// Comment. Ignore them.
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while( !(< '\r', '\n' >)[in[++pos]] );
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// Assume "xml\"" (xmlString)
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while( in[++pos]!='\"' )
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if( in[pos]=='\\' ) pos++;
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string str = decode_n_triple_string( in[start+1..pos-1] );
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tokens += ({ TempLiteral(str) });
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if( in[pos+1]=='^' ) {
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while(in[++pos]!='>');
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tokens[-1]->datatype = in[start..pos-1];
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// language (ignored)
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while( !(< ' ', '\t', '\r', '\n' >)[in[++pos]] );
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while( in[++pos]!='>' );
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tokens += ({ TempURI(decode_n_triple_string( in[start+1..pos-1] )) });
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error("No ':' in nodeID (position %s).\n", pos);
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while( !(< ' ', '\t', '\r', '\n' >)[in[++pos]] );
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tokens += ({ TempNode( in[start+2..pos-1] ) });
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error("Malformed n-triples input (position %d).\n", pos);
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mapping(string:Resource) anonymous = ([]);
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Resource make_resource(Temp res) {
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if(ret=uris[res->id])
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return URIResource( res->id );
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ret = LiteralResource( res->id );
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ret->datatype = res->datatype;
587
if(ret=anonymous[res->id])
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return anonymous[res->id]=Resource();
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error("Unknown temp container. Strange indeed.\n");
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foreach(tokens/({"."}), array rel) {
597
if(!sizeof(rel)) continue;
598
if(sizeof(rel)!=3) error("N-triple isn't a triple.\n");
599
add_statement( make_resource( rel[0] ),
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make_resource( rel[1] ),
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make_resource( rel[2] ) );
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//! Decodes a string that has been encoded for N-triples
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//! Doesn't correctly decode backslashes that has been
611
//! encoded with with \u- or \U-notation.
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string decode_n_triple_string(string in) {
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while( sscanf(in, "%s\\u%4x%s", string a, int b, in)==3 )
616
build += a + sprintf("%c", b);
620
while( sscanf(in, "%s\\U%8x%s", string a, int b, in)==3 )
621
build += a + sprintf("%c", b);
623
build = replace(build+in, ([ "\\\\" : "\\",
631
//! Encodes a string for use as tring in N-triples serialization.
632
string encode_n_triple_string(string in) {
635
foreach(in/1, string c) {
641
build += sprintf("\\u%4x", c[0]);
643
case 0x10000..0x10FFFF:
644
build += sprintf("\\U%8x", c[0]);
676
// #define Node Visconte.SemWeb.CustomNSTree.NSNode
678
static int dirty_namespaces = 1;
679
static mapping(string:string) namespaces = ([]); // url-prefix:name
680
static string common_ns = ""; // The most common namespace
683
static Visconte.SemWeb.CustomNSTree.NSNode add_xml_children(Visconte.SemWeb.CustomNSTree.NSNode p, string base) {
684
mapping rdf_m = p->get_ns_attributes(rdf_ns);
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base = p->get_ns_attributes("xml")->base || base;
686
if(rdf_m->about && rdf_m->ID)
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error("Both rdf:about and rdf:ID defined on the same element.\n");
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string subj_uri = rdf_m->about;
694
if (search(rdf_m->about, ":/") == -1)
695
rdf_m->about = base + rdf_m->about;
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subj = make_resource(rdf_m->about);
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subj = make_resource((base || "") + rdf_m->ID);
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add_statement(subj, rdf_type,
701
make_resource(p->get_ns()+p->get_any_name()) );
705
if(p->get_ns()!=rdf_ns)
706
add_statement( subj, rdf_type,
707
make_resource(p->get_ns()+p->get_any_name()) );
709
string name = p->get_any_name();
711
add_statement(subj, rdf_type, rdf_Seq);
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// Handle attribute abbreviation (2.2.2. Basic Abbreviated Syntax)
715
mapping m = p->get_ns_attributes();
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foreach(m; string ns; mapping m) {
717
if(ns==rdf_ns) continue;
718
foreach(m; string pred; string obj)
719
add_statement( subj, make_resource(ns+pred), LiteralResource(obj) );
722
int li_counter; // FIXME: Restart for every collection?
725
foreach(p->get_elements(), Visconte.SemWeb.CustomNSTree.NSNode c) {
726
if(c->get_ns()==rdf_ns) {
727
string name = c->get_any_name();
728
if(name=="type" || name=="first") {
729
string obj_uri = c->get_ns_attributes(rdf_ns)->resource;
730
if(!obj_uri) error("rdf:%s missing resource attribute.\n", name);
731
add_statement( subj, this["rdf_"+name], make_resource(obj_uri) );
735
string obj_uri = c->get_ns_attributes(rdf_ns)->resource;
736
if(obj_uri) add_statement( subj, rdf_rest, make_resource(obj_uri) );
737
array(Visconte.SemWeb.CustomNSTree.NSNode) dcs = c->get_elements();
738
foreach(dcs, Visconte.SemWeb.CustomNSTree.NSNode dc)
739
add_statement( subj, rdf_rest, add_xml_children(dc, base) );
742
else if(sscanf(name, "_%*d")) {
743
string obj_uri = c->get_ns_attributes(rdf_ns)->resource;
744
if(!obj_uri) error("rdf:_n missing resource attribute.\n");
745
add_statement( subj, make_resource(rdf_ns+name),
746
make_resource(obj_uri) );
749
else if(name=="li") {
750
string obj_uri = c->get_ns_attributes(rdf_ns)->resource;
751
if(!obj_uri) error("rdf:li missing resource attribute.\n");
752
add_statement( subj, make_resource(rdf_ns+"_"+(++li_counter)),
753
make_resource(obj_uri) );
757
// We are required to ignore unknown rdf elements.
758
error("Can not handle rdf:%s\n", c->get_any_name());
760
} // c->get_ns()==rdf_ns
762
string pred_uri = c->get_ns() + c->get_any_name();
764
string obj_uri = c->get_ns_attributes()[rdf_ns] &&
765
c->get_ns_attributes()[rdf_ns]->resource;
767
obj = make_resource(obj_uri);
768
mapping m = c->get_ns_attributes();
769
foreach(m; string ns; mapping m) {
770
if(ns==rdf_ns) continue;
771
foreach(m; string pred; string subobj)
772
add_statement( obj, make_resource(ns+pred),
773
LiteralResource(subobj) );
777
string ptype = c->get_ns_attributes(rdf_ns)->parseType;
778
if( !(< "Literal", "Resource", "Collection", 0 >)[ptype] )
779
error("Illegal parserType value %O.\n", ptype);
781
if(!ptype || ptype=="Resource") {
782
array(Visconte.SemWeb.CustomNSTree.NSNode) dcs = c->get_elements();
784
foreach(dcs, Visconte.SemWeb.CustomNSTree.NSNode dc)
785
add_statement( subj, make_resource(pred_uri),
786
add_xml_children(dc, base) );
790
else if(ptype=="Collection") {
791
// FIXME: Empty lists?
792
array(Visconte.SemWeb.CustomNSTree.NSNode) dcs = c->get_elements();
793
Resource n = Resource();
794
add_statement( subj, make_resource(pred_uri), n );
795
foreach(dcs; int pos; Visconte.SemWeb.CustomNSTree.NSNode dc) {
796
add_statement( n, rdf_first, add_xml_children(dc, base) );
797
if(pos<sizeof(dcs)-1)
798
add_statement( n, rdf_rest, n=Resource() );
800
add_statement( n, rdf_rest, rdf_nil );
804
// ptype == "Literal"
806
obj = LiteralResource((array(string))c->get_children()*"");
807
obj->datatype = c->get_ns_attributes(rdf_ns)->datatype;
809
add_statement( subj, make_resource(pred_uri), obj );
815
//! @decl Web.RDF parse_xml(string|.Parser.XML.NSTree.NSNode in, @
816
//! void|string base)
817
//! Adds the statements represented by the string or tree @[in] to the
818
//! RDF domain. If @[in] is a tree the in-node should be the @tt{RDF@}
819
//! node of the XML serialization. RDF documents take its default
820
//! namespace from the URI of the document, so if the RDF document relies
821
//! such ingenious mechanisms, pass the document URI in the @[base]
823
this_program parse_xml(string|Visconte.SemWeb.CustomNSTree.NSNode in, void|string base) {
824
Visconte.SemWeb.CustomNSTree.NSNode n;
826
n = Visconte.SemWeb.CustomNSTree.parse_input(in);
827
n = n->get_first_element("RDF");
832
// Determine the document base.
833
base = n->get_ns_attributes("xml")->base || base || "";
835
// FIXME: Namespaces defined under the rdf-element will not be used
837
mapping nss = n->get_defined_nss();
838
foreach(values(nss), string name)
839
if( !namespaces[name] ) {
840
namespaces = mkmapping(values(nss),indices(nss))|namespaces;
841
dirty_namespaces = 1;
845
foreach(n->get_elements(), Visconte.SemWeb.CustomNSTree.NSNode c)
846
add_xml_children(c, base);
851
static void fix_namespaces() {
852
if(!dirty_namespaces) return;
853
mapping(string:string) new = ([]);
854
mapping(string:int) stat = ([]);
856
foreach(indices(uris), string uri) {
858
[ uri, obj ] = uri_parts(uri);
862
else if( namespaces[uri] )
863
new[uri] = namespaces[uri];
867
ns = default_ns[uri] || "ns"+(i++);
869
while( has_value(new, ns) || has_value(namespaces, ns) );
876
array nss = indices(stat);
877
array occur = values(stat);
881
dirty_namespaces = 0;
886
String.Buffer buf = String.Buffer();
887
mapping subjects = get_subject_map();
891
void add_ns(Resource r) {
892
string s=r->get_namespace();
893
ns[s] = namespaces[s];
896
void low_add_Description( mapping(Resource:array(Resource)) rel ) {
899
foreach(rel; Resource left; array(Resource) rights) {
900
foreach(rights, Resource right) {
901
if(right->is_literal_resource) {
902
if(ind) buf->add(" "*ind);
903
buf->add("<", left->get_qname());
905
buf->add(" rdf:datatype='", right->datatype, "'");
906
buf->add(">", right->get_xml(), "</", left->get_qname(), ">\n");
908
else if(right->is_uri_resource) {
909
if(ind) buf->add(" "*ind);
910
buf->add("<", left->get_qname());
911
buf->add(" rdf:resource='", right->get_uri(), "'/>\n");
914
group += ({ right });
917
if(ind) buf->add(" "*ind);
918
buf->add("<", left->get_qname(), ">\n");
920
foreach(group, Resource right)
921
add_Description(right, m_delete(subjects, right)||([]));
924
if(ind) buf->add(" "*ind);
925
buf->add("</", left->get_qname(), ">\n");
927
add_ns(left); // We must add_ns after get_qname to fix_namespaces.
932
string make_prop_attr(mapping(Resource:array(Resource)) rel,
934
foreach(rel; Resource left; array(Resource) rights) {
935
if(!left->is_uri_resource) continue;
936
foreach(rights; int p; Resource right) {
937
if(!right->is_literal_resource) continue;
938
if(right->datatype) continue;
939
if(has_value(right->get_xml(), "\n")) continue;
941
buf->add("\n", " "*ind, " "*i2);
942
buf->add(left->get_qname(), "='", right->get_xml(), "'");
954
void add_Description(Resource n,
955
mapping(Resource:array(Resource)) rel) {
956
if(n->is_literal_resource)
957
error("Can not serialize literal resource as subject.\n");
959
// Can we make a <foo></foo> instead of
960
// <Description><rdf:type rdf:resource="foo"/></Description>
962
Resource c = rel[rdf_type][0];
963
if(sizeof(rel[rdf_type])>1)
964
rel[rdf_type] = rel[rdf_type][1..];
966
m_delete(rel, rdf_type);
967
if(ind) buf->add(" "*ind);
968
buf->add("<", c->get_qname());
970
if(n->is_uri_resource) {
971
buf->add(" rdf:about='", n->get_uri(), "'");
972
make_prop_attr(rel, 1, sizeof(c->get_qname())+2);
976
make_prop_attr(rel, 0, sizeof(c->get_qname())+2);
979
low_add_Description(rel);
980
if(ind) buf->add(" "*ind);
981
buf->add("</", c->get_qname(), ">\n");
984
if(ind) buf->add(" "*ind);
985
if(n->is_uri_resource) {
986
buf->add("<rdf:Description rdf:about='", n->get_uri(), "'");
987
make_prop_attr(rel, 1, 17);
990
buf->add("<rdf:Description ");
991
make_prop_attr(rel, 0, 17);
996
if(!ind) buf->add("\n");
1002
low_add_Description(rel);
1003
if(ind) buf->add(" "*ind);
1004
buf->add("</rdf:Description>\n");
1006
if(!ind) buf->add("\n");
1013
// First all root resources.
1014
foreach(subjects; Resource n;
1015
mapping(Resource:array(Resource)) rel) {
1016
if(is_object(n) || is_predicate(n)) continue;
1017
m_delete(subjects, n);
1018
add_Description(n, rel);
1021
// Then all named resources.
1022
foreach(subjects; Resource n;
1023
mapping(Resource:array(Resource)) rel) {
1024
if(!n->is_uri_resource) continue;
1025
m_delete(subjects, n);
1026
add_Description(n, rel);
1029
// Cyclic/unreferenced unnamed resources and literals.
1030
if(sizeof(subjects))
1031
error("Unserialized resources left.\n");
1033
String.Buffer ret = String.Buffer();
1034
ret->add("<?xml version='1.0'?>\n"
1035
"<rdf:RDF\nxmlns='" + common_ns +"'\n"
1036
"xmlns:rdf='" +rdf_ns + "'\n");
1037
foreach(ns; string url; string name) {
1038
if(url==common_ns) continue;
1039
ret->add("xmlns:", name, "='", url, "'\n");
1042
ret->add( (string)buf );
1043
ret->add("</rdf:RDF>\n");
1049
//! Serialize the RDF domain as an XML string.
1051
return XML()->render();
1059
//! Returns the number of statements in the RDF domain.
1060
static int _sizeof() {
1061
if(!sizeof(statements)) return 0;
1062
return `+( @sizeof(values(statements)[*]) );
1065
static string _sprintf(int t) {
1066
return t=='O' && sprintf("%O(%d)", this_program, _sizeof());
1069
//! @decl Web.RDF `|(Web.RDF x)
1070
//! Modifies the current object to create a union of the current object
1071
//! and the object @[x].
1072
static this_program `|(mixed data) {
1073
if(sprintf("%t", data)!="object" ||
1074
!functionp(data->find_statements))
1075
error("Can only or an RDF object with another RDF object.\n");
1077
Resource normalize(Resource r) {
1078
if(r->is_literal_resource) return r;
1079
if(r==data->rdf_Statement) return rdf_Statement;
1080
if(r==data->rdf_predicate) return rdf_predicate;
1081
if(r==data->rdf_subject) return rdf_subject;
1082
if(r==data->rdf_object) return rdf_object;
1083
if(r==data->rdf_type) return rdf_type;
1084
if(!functionp(r->get_uri)) return r;
1085
return make_resource(r->get_uri());
1088
foreach(data->find_statements(),
1089
[Resource subj, Resource pred, Resource obj])
1090
add_statement(normalize(subj), normalize(pred), normalize(obj));
added
removed
server/libraries/Visconte.pmod/SemWeb.pmod/RDF.pike
