Network Working Group P. Thierry Internet-Draft Thierry Technologies Intended status: Experimental August 7, 2013 Expires: February 8, 2014 BULK RDF namespace draft-thierry-bulk-rdf-00 Abstract This specification describes a BULK serialization of RDF ontologies and graphs. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on February 8, 2014. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Thierry Expires February 8, 2014 [Page 1] Internet-Draft BULK-RDF August 2013 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Conventions and Terminology . . . . . . . . . . . . . . . . 3 2. BULK RDF namespace . . . . . . . . . . . . . . . . . . . . . . 3 2.1. URI reference . . . . . . . . . . . . . . . . . . . . . . . 3 2.2. Base URI . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.3. URI prefix . . . . . . . . . . . . . . . . . . . . . . . . 4 2.4. blank . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.5. RDF literals . . . . . . . . . . . . . . . . . . . . . . . 4 2.5.1. Plain literal . . . . . . . . . . . . . . . . . . . . . 4 2.5.2. Typed literal . . . . . . . . . . . . . . . . . . . . . 5 2.5.3. XMLLiteral . . . . . . . . . . . . . . . . . . . . . . 5 2.6. Triples . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.7. Turtle-like statements . . . . . . . . . . . . . . . . . . 5 2.8. RDF vocabulary . . . . . . . . . . . . . . . . . . . . . . 5 2.9. RDF embedding . . . . . . . . . . . . . . . . . . . . . . . 6 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 4. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1. Normative References . . . . . . . . . . . . . . . . . . . 7 4.2. Informative references . . . . . . . . . . . . . . . . . . 7 Appendix A. Example: RDF Schema vocabulary . . . . . . . . . . . . 8 Thierry Expires February 8, 2014 [Page 2] Internet-Draft BULK-RDF August 2013 1. Introduction 1.1. Conventions and Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Literal numerical values are provided in decimal or hexadecimal as appropriate. Hexadecimal literals are prefixed with "0x" to distinguish them from decimal literals. BULK bytes sequences and expressions are described with the same conventions than used in the BULK 1.0 specification [BULK1] 2. BULK RDF namespace The RDF namespace is an official namespace identified by the UUID (BULK, "http://www.w3.org/1999/02/22-rdf-syntax-ns#"). Its first purpose is to serialize both RDF ontologies and graphs, but as RDF is deeply rooted in the World Wide Web and the REST architecture, some of the names and forms defined in this specification are intended to be used in applications related to those. This specification defines the type "URIString", which is an array whose content is a string conforming to the "URI-reference" production in [RFC3986] (section 4.1). 2.1. URI reference name "0x1" (mnemonic: "uriref" ) shape "( uriref URIString )" This form makes it possible to differentiate a string containing a URI from a URI reference itself. Type: "URIRef" 2.2. Base URI name "0x2" (mnemonic: "base" ) shape "( base URIString )" This form changes the current base URI for URI resolution. If the given URI is relative, it must be resolved with the current base URI. Thierry Expires February 8, 2014 [Page 3] Internet-Draft BULK-RDF August 2013 2.3. URI prefix name "0x3" (mnemonic: "prefix" ) shape "( prefix {uri} )" Name's type EagerFunction Form's type EagerFunction Form's value a function that returns a URIRef whose content is the concatenation of {uri} and its only argument (or returns {uri} if called without arguments) {uri} can be of type "URIString" or "URIRef". If it is of type URIRef, the above description should be taken as if the form is of shape "( prefix ( uriref {uri} ) )". 2.4. blank name "0x4" (mnemonic: "blank" ) shape "( blank )" Name's type EagerFunction Form's type Expr Form's value a new blank node. If a same blank node must be used in several forms, it should be made the value of a name. 2.5. RDF literals Literals are arbitrary data that can be an object in an RDF triple. It is important to note that their BULK serialization doesn't need to denote the string of their lexical form. Any array used as object in an RDF triple has the semantics of a plain literal without language tag. 2.5.1. Plain literal name "0x5" (mnemonic: "plain" ) shape "( plain {lang}:Array {literal}:Array )" This is a plain RDF literal. {lang} is the language tag. Thierry Expires February 8, 2014 [Page 4] Internet-Draft BULK-RDF August 2013 2.5.2. Typed literal name "0x6" (mnemonic: "type" ) shape "( type {id}:URIRef {literal} )" This is a typed RDF literal. {id} is the datatype URI. Each type defines what is legal as "{literal}". 2.5.3. XMLLiteral name "0x7" (mnemonic: "xmlliteral" ) value "( uriref "http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral" )" A literal with this type SHOULD contain a BULK serialization of XML (cf. [BULK-XML]). An application MUST NOT use an array for this literal for anyhting else than a string that belongs to the lexical space defined for . 2.6. Triples name "0x8" (mnemonic: "triples" ) shape "( triples {triples} )" "{triples}" must be a sequence of "( {subj}:URIRef {pred}:URIRef {obj} )". 2.7. Turtle-like statements name "0x9" (mnemonic: "turtle" ) shape "( turtle {statements} )" "{statements}" MUST be a sequnce of "( {subj}:URIRef {preds} )", where "{preds}" MUST be a sequence of "( {pred}:URIRef {objs} )", where "{objs}" is a sequence. 2.8. RDF vocabulary The following names are associated with "uriref" forms, with a base URI of . Their mnemonic is the lowercased URI reference. Thierry Expires February 8, 2014 [Page 5] Internet-Draft BULK-RDF August 2013 0xA type 0xB Property 0xC Statement 0xD subject 0xE predicate 0xF object 0x10 Bag 0x11 Seq 0x12 Alt 0x13 value 0x14 List 0x15 nil 0x16 first 0x17 rest 0x18 PlainLiteral 2.9. RDF embedding name "0x20" (mnemonic: "this-resource" ) shape "this-resource" This expression is intended to help embedding RDF metadata alongside or within a resource. It has the semantics of a blank node that designates this resource. What makes a resource the current described resource is application-dependent. 3. Security Considerations 4. References Thierry Expires February 8, 2014 [Page 6] Internet-Draft BULK-RDF August 2013 4.1. Normative References [BULK1] Thierry, P., "Binary Uniform Language Kit 1.0", draft-thierry-bulk-02 (work in progress), August 2013. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 3986, STD 66, January 2005. 4.2. Informative references [BULK-XML] Thierry, P., "BULK Simple XML namespace", draft-thierry-bulk-xml-00 (work in progress), August 2013. [RDF-CONCEPTS] Klyne, G. and J. Carroll, "Resource Description Framework (RDF): Concepts and Abstract Syntax", February 2004, . Thierry Expires February 8, 2014 [Page 7] Internet-Draft BULK-RDF August 2013 Appendix A. Example: RDF Schema vocabulary Here is the text notation of a BULK stream defining references for each element in the RDF Schema vocabulary. The whole stream is 444 bytes in length. ( bulk:version 1 0 ) ( bulk:ns 32 rdf ) ( bulk:ns* 33 rdfs ) ( define rdfs:schema ( prefix "http://www.w3.org/2000/01/rdf-schema#" ) ) ( define rdfs:resource ( rdfs:schema "Resource" ) ) ( define rdfs:class ( rdfs:schema "Class" ) ) ( define rdfs:subclassof ( rdfs:schema "subClassOf" ) ) ( define rdfs:subpropertyof ( rdfs:schema "subPropertyOf" ) ) ( define rdfs:comment ( rdfs:schema "comment" ) ) ( define rdfs:label ( rdfs:schema "label" ) ) ( define rdfs:domain ( rdfs:schema "domain" ) ) ( define rdfs:range ( rdfs:schema "range" ) ) ( define rdfs:seealso ( rdfs:schema "seeAlso" ) ) ( define rdfs:isdefinedby ( rdfs:schema "isDefinedBy" ) ) ( define rdfs:literal ( rdfs:schema "Literal" ) ) ( define rdfs:container ( rdfs:schema "Container" ) ) ( define rdfs:containermembershipproperty ( rdfs:schema "ContainerMembershipProperty" ) ) ( define rdfs:member ( rdfs:schema "member" ) ) ( define rdfs:datatype ( rdfs:schema "Datatype" ) ) ( define rdfs:schema* ( rdfs:schema ) ) Thierry Expires February 8, 2014 [Page 8] Internet-Draft BULK-RDF August 2013 Here is the text notation of a BULK stream containg a small part of the RDF Schema ontology. The whole stream is 375 bytes in length (the corresponding RDF/XML document would be 1525 bytes in length). ( bulk:version 1 0 ) ( bulk:ns 32 rdf ) ( bulk:ns 33 rdfs ) ( turtle ( rdfs:resource ( rdf:type rdfs:class ) ( rdfs:isdefinedby rdfs:schema* ) ( rdfs:label "Resource" ) ( rdfs:comment "The class resource, everything." ) ) ( rdfs:class ( rdf:type rdfs:class ) ( rdfs:isdefinedby rdfs:schema* ) ( rdfs:label "Class" ) ( rdfs:comment "The class of classes." ) ( rdfs:subclassof rdfs:resource ) ) ( rdfs:subclassof ( rdf:type rdf:property ) ( rdfs:isdefinedby rdfs:schema* ) ( rdfs:label "subClassOf" ) ( rdfs:comment "The subject is a subclass of a class." ) ( rdfs:range rdfs:class ) ( rdfs:domain rdfs:class ) ) ( rdfs:subpropertyof ( rdf:type rdf:property ) ( rdfs:isdefinedby rdfs:schema* ) ( rdfs:label "subPropertyOf" ) ( rdfs:comment "The subject is a subproperty of a property." ) ( rdfs:range rdf:property ) ( rdfs:domain rdf:property ) ) ) Author's Address Pierre Thierry Thierry Technologies EMail: pierre@nothos.net Thierry Expires February 8, 2014 [Page 9]