Network Working Group P. Stickler Internet-Draft NRC Expires: July 17, 2002 January 16, 2002 The 'tdl:' URI Scheme for Typed Data Literals draft-pstickler-tdl-00 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on July 17, 2002. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract This document describes the 'tdl:' Uniform Resource Identifier (URI) scheme for Typed Data Literals Stickler Expires July 17, 2002 [Page 1] Internet-Draft The 'tdl:' URI Scheme January 2002 Table of Contents 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. BNF for the 'tdl:' URI Scheme . . . . . . . . . . . . . . . . . 3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 Full Copyright Statement . . . . . . . . . . . . . . . . . . . . 6 Stickler Expires July 17, 2002 [Page 2] Internet-Draft The 'tdl:' URI Scheme January 2002 1. Overview The 'tdl:' URI scheme is intended to provide a simple but consistent means by which a data literal (lexical form) can be paired with a datatype URI allowing one to denote the unique data value represented by that pairing. The 'tdl:' URI scheme belongs to the class of URIs known as Uniform Resource Values (URV) which are themselves a subclass of Uniform Resource Primitives (URP), a class of URI which constitutes a "WYSIWYG" URI, one which is not dereferencible to and does not denote another web resource, but constitutes a self-contained resource where the full realization of that resource is expressed in the URI itself. For a full discussion of the properties of URPs and URVs, please see [4]. Familiarity with the concepts defined therein will facilitate the full understanding of this document. Examples: tdl:(http://www.w3.org/2001/XMLSchema#integer)15 tdl:(http://www.w3.org/2001/XMLSchema#lang)fi tdl:(http://www.w3.org/2001/XMLSchema#NMTOKENS)foo%20bar%20bas tdl:(http://dodo.xyz.net/x-token)foo tdl:(voc://john.doe@widgets.org/xycoord)28.191 tdl:(uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6)392f291a093 These examples are provided for illustrative purposes only and do not necessarily constitute actual URIs. See the BNF definition below for an explicit definition of 'tdl:' URI syntax. 'tdl:' URIs are particularly useful for applications such as RDF [5] where one may wish to make statements about such value resources. E.g. Finnish There is the additional benefit that if canonical lexical forms are used, every data value represented by a 'tdl:' URI in an RDF graph will share a common graph node, which both provides a considerable amount of graph compression compared to other literal datatyping schemes as well as facilitates queries or inference based on typed data values. 2. BNF for the 'tdl:' URI Scheme This is a BNF-like description of the 'tdl:' Uniform Resource Stickler Expires July 17, 2002 [Page 3] Internet-Draft The 'tdl:' URI Scheme January 2002 Identifier syntax, using the conventions of RFC 822[2], except that "|" is used to designate alternatives, and brackets [] are used around optional or repeated elements. Briefly, literals are quoted with "", optional elements are enclosed in [brackets], and elements may be preceded with * to designate n or more repetitions of the following element; n defaults to 0. This BNF description adopts sub-definitions defined in RFC 2396 "Uniform Resource Identifiers (URI): Generic Syntax" [1] which are not repeated here. tdl-URI = "tdl:" "(" type ")" value type = absoluteURI [ "#" fragment ] value = 1*uric absoluteURI = fragment = uric = Note that the URI scheme prefix "tdl:" is considered to be a valid URI denoting this URI scheme, though it is not itself a valid URI according to this URI scheme. References [1] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. [2] Crocker, D., "STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES", RFC 822, August 1982. [3] International Organization for Standardization, "ISO/IEC 11578:1996 Information technology -- Open Systems Interconnection -- Remote Procedure Call", August 2001. [4] Stickler, P., "An Extended Class Taxonomy of Uniform Resource Identifier Schemes", January 2002, . [5] Lassila, O. and R. Swick, "Resource Description Framework (RDF) Model and Syntax Specification", February 1999, . Stickler Expires July 17, 2002 [Page 4] Internet-Draft The 'tdl:' URI Scheme January 2002 Author's Address Patrick Stickler Nokia Research Center Visiokatu 1 Tampere 33720 FI EMail: patrick.stickler@nokia.com Stickler Expires July 17, 2002 [Page 5] Internet-Draft The 'tdl:' URI Scheme January 2002 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. 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