INTERNET-DRAFT S. Legg draft-legg-xed-glue-02.txt Adacel Technologies Intended Category: Standards Track D. Prager Deakin University June 15, 2004 The XML Enabled Directory: Schema Language Integration Copyright (C) The Internet Society (2004). All Rights Reserved. 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. Distribution of this document is unlimited. Technical discussion of this document should take place on the XED developers mailing list . Please send editorial comments directly to the editor . This Internet-Draft expires on 15 December 2004. Abstract This document defines the means by which an Abstract Syntax Notation One (ASN.1) specification can incorporate the definitions of types and elements in specifications written in other Extensible Markup Language (XML) schema languages. References to XML Schema types and elements, RELAX NG named patterns and elements, and Document Type Legg & Prager Expires 15 December 2004 [Page 1] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 Declaration element types are supported. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions. . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Representing Markup as ASN.1 Values. . . . . . . . . . . . . . 3 4. Supporting ASN.1 Types . . . . . . . . . . . . . . . . . . . . 5 4.1. The AnyURI Type. . . . . . . . . . . . . . . . . . . . . 5 4.2. The NCName Type. . . . . . . . . . . . . . . . . . . . . 6 4.3. The Name Type. . . . . . . . . . . . . . . . . . . . . . 6 5. Referencing Foreign Types. . . . . . . . . . . . . . . . . . . 6 5.1. Referencing Type Definitions . . . . . . . . . . . . . . 6 5.2. DTD Element Types as Types . . . . . . . . . . . . . . . 8 6. Referencing Foreign Elements . . . . . . . . . . . . . . . . . 9 6.1. Referencing Element Definitions. . . . . . . . . . . . . 10 6.2. DTD Element Types as Elements. . . . . . . . . . . . . . 11 7. Security Considerations. . . . . . . . . . . . . . . . . . . . 12 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 9.1. Normative References . . . . . . . . . . . . . . . . . . 12 9.2. Informative References . . . . . . . . . . . . . . . . . 13 Appendix A. ASN.1 for Schema Language Integration. . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 16 1. Introduction This document defines the means by which an Abstract Syntax Notation One (ASN.1) [X680] specification can incorporate the definitions of types and elements in specifications written in other Extensible Markup Language (XML) [XML] schema languages. References to XML Schema [XSD1] types and elements, RELAX NG [RNG] named patterns and elements, and Document Type Declaration (DTD) [XML] element types are supported. Non-ASN.1 definitions are supported by first defining an ASN.1 type whose values can contain arbitrary markup, and then defining constraints on that type to restrict the content to specific nominated datatypes from non-ASN.1 schema definitions. The ASN.1 definitions in this document are consolidated in Appendix A. 2. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", and "MAY" in this document are Legg & Prager Expires 15 December 2004 [Page 2] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 to be interpreted as described in BCP 14, RFC 2119 [BCP14]. The key word "OPTIONAL" is exclusively used with its ASN.1 meaning. This specification makes use of definitions from the XML Information Set (Infoset) [ISET]. The term "element" shall be taken to mean an Infoset element information item. The term "attribute" shall be taken to mean an Infoset attribute information item. A reference to a ASN.1 production [X680] (e.g., Value, UserDefinedConstraint) is a reference to the text in an ASN.1 specification corresponding to that production. 3. Representing Markup as ASN.1 Values A value of the AnyType ASN.1 type holds arbitrary content of an element (but not the start-tag and end-tag, or empty-element tag), plus the context required to correctly interpret that content. AnyType ::= CHOICE { text [0] SEQUENCE { prolog [0] UTF8String (SIZE(1..MAX)) OPTIONAL, context [1] UTF8String (SIZE(1..MAX)) OPTIONAL, attributes [2] UTF8String (SIZE(1..MAX)) OPTIONAL, content [3] UTF8String (SIZE(1..MAX)) OPTIONAL } } } The text alternative of the AnyType CHOICE type provides for the [attributes] and [children] of an element to be represented as verbatim text using the UTF-8 character encoding. The CHOICE allows for one or more alternative compact representations of the content of elements to be supported in a future specification. With respect to some element whose content is represented by a value of the text alternative of the AnyType type: - the prolog component of the value contains, from the XML document containing the element, the text corresponding to the prolog production [XML], or the sufficient (well-formed and valid) part thereof to define the entity references appearing in the context, attributes and content components of the value, - the context component of the value contains a whitespace separated list of the [namespace attributes] of the ancestors of the element, if any, plus any [attributes] of the ancestor elements which are inherited by their element children, - the attributes component of the value contains text corresponding to the [attributes] of the element, if any, Legg & Prager Expires 15 December 2004 [Page 3] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 - the content component of the value contains the text of the content of the element between the start-tag and end-tag. The component is absent if there are no characters between the start-tag and end-tag, or if the element uses an empty-element tag. Leading and trailing whitespace corresponding to the S production [XML] in the prolog, context and attributes components MAY be omitted. Multiple whitespace characters corresponding to the S production in the prolog, context and attributes components MAY be replaced with a single space character. Any entity references in the context, attributes and content components MAY be replaced by their replacement text so that the prolog component can be omitted. If the prolog component is absent then XML version 1.0 is assumed. Note that the Robust XML Encoding Rules [RXER] have special provisions for encoding values of the AnyType type. For other encoding rules, values of the AnyType type are encoded according to the ASN.1 type definition of AnyType. Example Consider the following XML document: ]> &TRUE; The AnyType value corresponding to the content of the element is, in ASN.1 value notation [X680]: text:{ prolog { "", lf, "", lf "]>", lf }, context "xmlns:ns=""http://www.example.com/SLI""", attributes " ns:foo=""1"" bar=""0""", Legg & Prager Expires 15 December 2004 [Page 4] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 content { lf, " &TRUE;", lf, " ", lf, " " } } The following AnyType value is also an acceptable representation of the content of the element: text:{ context "xmlns:ns=""http://www.example.com/SLI""", attributes "bar=""0"" ns:foo=""1""", content { lf, " true", lf, " ", lf, " " } } By itself the AnyType ASN.1 type imposes no datatype restriction on the markup contained by its values, and is therefore analogous to the XML Schema anyType [XSD1]. There is no ASN.1 notation that can directly impose the constraint that a value of the AnyType type must conform to the markup allowed by a specific non-ASN.1 definition. However, UserDefinedConstraint notation [X682] can be exploited to provide parameters to nominated predefined constraints that have the desired effect. A predefined constraint is identified by an OBJECT IDENTIFIER value passed as a parameter in a UserDefinedConstraint. Though the UserDefinedConstraint notation does not express the semantics of a constraint, multi-schema aware ASN.1 tools can recognize particular OBJECT IDENTIFIER values (defined later in this document) and behave appropriately. These OBJECT IDENTIFIER values have id-constraint as a common prefix. id-constraint OBJECT IDENTIFIER ::= { iso(1) 2 36 79672281 xed(3) constraint(1) } 4. Supporting ASN.1 Types This section defines ASN.1 types that support the application of constraints on the markup allowed in values of the AnyType ASN.1 type. 4.1. The AnyURI Type A value of the AnyURI ASN.1 type is a URI character string [URI]. AnyURI ::= UTF8String (CONSTRAINED BY Legg & Prager Expires 15 December 2004 [Page 5] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 { -- conforms to the format of a URI -- }) 4.2. The NCName Type A value of the NCName ASN.1 type is a character string conforming to the NCName production of Namespaces in XML [XMLNS]. NCName ::= UTF8String (CONSTRAINED BY { -- conforms to the NCName production of -- Namespaces in XML -- }) 4.3. The Name Type A value of the Name ASN.1 type is a character string conforming to the Name production of XML [XML]. Name ::= UTF8String (CONSTRAINED BY { -- conforms to the Name production of XML -- }) 5. Referencing Foreign Types To incorporate a non-ASN.1 datatype into an ASN.1 specification it is necessary to constraint values of the AnyType ASN.1 type to contain only markup valid with respect to that datatype. XML Schema and RELAX NG both have distinct definitional forms for elements and types (named patterns in RELAX NG). A DTD element type declaration can be regarded as defining either a complete element, or the content of an element (i.e., a type). 5.1. Referencing Type Definitions The values of the AnyType ASN.1 type can be restricted to conform to a specific XML Schema named type or RELAX NG named pattern by applying a UserDefinedConstraint containing the value of id-constraint-xml-type as a parameter. id-constraint-xml-type OBJECT IDENTIFIER ::= { id-constraint 0 } A UserDefinedConstraint in which an OBJECT IDENTIFIER with the value of id-constraint-xml-type is used MUST satisfy all of the following conditions: a) there SHALL be three or four UserDefinedConstraintParameters, b) the first UserDefinedConstraintParameter SHALL be a Value of the OBJECT IDENTIFIER ASN.1 type and that Value SHALL be the same as id-constraint-xml-type, Legg & Prager Expires 15 December 2004 [Page 6] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 c) the second UserDefinedConstraintParameter SHALL be a Value of the AnyURI ASN.1 type (possibly an empty string), d) the third UserDefinedConstraintParameter SHALL be a Value of the NCName ASN.1 type, e) the fourth UserDefinedConstraintParameter, if present, SHALL be a Value of the AnyURI ASN.1 type, f) taken together the second and third UserDefinedConstraintParameter SHALL be the namespace name and local name [XMLNS] of either an XML Schema type definition or a RELAX NG named pattern. The fourth UserDefinedConstraintParameter is used when the namespace name and local name reference is ambiguous, i.e., refers to definitions in more than one schema document. This situation would occur, for example, when importing types with the same name from independently developed XML Schemas defined without a target namespace. The value of the fourth UserDefinedConstraintParameter is a URI that indicates the intended schema document, either an XML Schema specification or a RELAX NG specification. Example AnyType (CONSTRAINED BY { OBJECT IDENTIFIER: { iso(1) 2 36 79672281 xed(3) constraint(1) 0 }, AnyURI:"http://www.w3.org/2001/XMLSchema", NCName:"decimal" }) The XML-Type and XML-Type-From-Schema parameterized types [X683] are defined so that XML Schema named types and RELAX NG named patterns can be more conveniently referenced. XML-Type { AnyURI:namespace, NCName:name } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-xml-type, AnyURI:namespace, NCName:name }) XML-Type-From-Schema { AnyURI:namespace, NCName:name, AnyURI:schemaIdentity } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-xml-type, AnyURI:namespace, NCName:name, AnyURI:schemaIdentity }) Example The following notation is sufficient to incorporate the xsd:decimal XML Schema type as the member type in a SEQUENCE OF type definition: Legg & Prager Expires 15 December 2004 [Page 7] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 SEQUENCE OF number XML-Type { "http://www.w3.org/2001/XMLSchema", "decimal" } Note that the ASN.1 Schema [ASD] translation of this ASN.1 type provides a more natural way to reference the XML Schema decimal type: The XML-Type parameterized type cannot be used if the URI of a schema document is required to disambiguate the namespace name and local name. The XML-Type-From-Schema parameterized type can be used instead. 5.2. DTD Element Types as Types The values of the AnyType ASN.1 type can be restricted to conform to the content specified by a nominated DTD element type declaration by applying a UserDefinedConstraint containing the value of id-constraint-dtd-type as a parameter. id-constraint-dtd-type OBJECT IDENTIFIER ::= { id-constraint 2 } A UserDefinedConstraint in which an OBJECT IDENTIFIER with the value of id-constraint-dtd-type is used MUST satisfy all of the following conditions: a) there SHALL be three UserDefinedConstraintParameters, b) the first UserDefinedConstraintParameter SHALL be a Value of the OBJECT IDENTIFIER ASN.1 type and that Value SHALL be the same as id-constraint-dtd-type, c) the second UserDefinedConstraintParameter SHALL be a Value of the AnyURI ASN.1 type specifying the system identifier of an external DTD subset [XML], d) the third UserDefinedConstraintParameter SHALL be a Value of the Name ASN.1 type specifying an element type declaration in the external DTD subset nominated by the second parameter. Example Suppose that the following external DTD subset has been defined Legg & Prager Expires 15 December 2004 [Page 8] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 with a system identifier of "http://www.example.com/inventory": Values of AnyType can be restricted to conform to the content specified by the product element type declaration using the following notation: AnyType (CONSTRAINED BY { OBJECT IDENTIFIER: { iso(1) 2 36 79672281 xed(3) constraint(1) 2 }, AnyURI:"http://www.example.com/inventory", Name:"product" }) The DTD-Type parameterized type [X683] is defined so that DTD element type declarations can be more conveniently referenced. DTD-Type { AnyURI:schemaIdentity, Name:name } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-dtd-type, AnyURI:schemaIdentity, Name:name }) Example The following ASN.1 notation is sufficient to incorporate the product element type into an ASN.1 specification as the member type in a SEQUENCE OF type definition: SEQUENCE OF inventoryItem DTD-Type { "http://www.example.com/inventory", "product" } Note that when an element type declaration is referenced as a type, the Name of the element type declaration does not contribute to the RXER encoding of values of the resulting type. For example, child elements in the RXER encoding of values of the above SEQUENCE OF type would resemble the following: 6. Referencing Foreign Elements ASN.1 does not have a construct analogous to a global element definition, hence there is no analogy in ASN.1 for referencing a global element definition (though there is in ASN.1 Schema). Legg & Prager Expires 15 December 2004 [Page 9] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 The AnyType ASN.1 type represents the content of an element. To import an element from a non-ASN.1 specification it is necessary to regard that element as the child element of a notional type whose content model permits only the imported element. The notional type is arbitrarily chosen to be a choice type. The notional type does not define any attributes therefore the attributes component of a value of the text alternative of AnyType would normally be empty, or contain only namespace declaration attributes. 6.1. Referencing Element Definitions The values of the AnyType ASN.1 type can be restricted to conform to a notional choice type containing a specific XML Schema element or RELAX NG element by applying a UserDefinedConstraint containing the value of id-constraint-xml-element as a parameter. id-constraint-xml-element OBJECT IDENTIFIER ::= { id-constraint 1 } A UserDefinedConstraint in which an OBJECT IDENTIFIER with the value of id-constraint-xml-element is used MUST satisfy all of the following conditions: a) there SHALL be three or four UserDefinedConstraintParameters, b) the first UserDefinedConstraintParameter SHALL be a Value of the OBJECT IDENTIFIER ASN.1 type and that Value SHALL be the same as id-constraint-xml-element, c) the second UserDefinedConstraintParameter SHALL be a Value of the AnyURI ASN.1 type (possibly an empty string), d) the third UserDefinedConstraintParameter SHALL be a Value of the NCName ASN.1 type, e) the fourth UserDefinedConstraintParameter, if present, SHALL be a Value of the AnyURI ASN.1 type, f) taken together the second and third UserDefinedConstraintParameter SHALL be the namespace name and local name [XMLNS] of either an XML Schema element definition or a RELAX NG element definition. The fourth UserDefinedConstraintParameter is used when the namespace name and local name reference is ambiguous. Its value is a URI that indicates the intended schema document, either an XML Schema specification or a RELAX NG specification. Legg & Prager Expires 15 December 2004 [Page 10] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 Example AnyType (CONSTRAINED BY { OBJECT IDENTIFIER: { iso(1) 2 36 79672281 xed(3) constraint(1) 1 }, AnyURI:"http://www.example.com/IPO", NCName:"purchaseOrder" }) The Contained-XML-Element and Contained-XML-Element-From-Schema parameterized types are defined so that XML Schema global elements and RELAX NG elements can be more conveniently referenced. Contained-XML-Element { AnyURI:namespace, NCName:name } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-xml-element, AnyURI:namespace, NCName:name }) Contained-XML-Element-From-Schema { AnyURI:namespace, NCName:name, AnyURI:schemaIdentity } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-xml-element, AnyURI:namespace, NCName:name, AnyURI:schemaIdentity }) The Contained-XML-Element type cannot be used if the URI of a schema document is required to disambiguate the target namespace and name. The Contained-XML-Element-From-Schema parameterized type can be used instead. 6.2. DTD Element Types as Elements The values of the AnyType ASN.1 type can be restricted to conform to a notional choice type containing an element with the name and content specified by a nominated DTD element type declaration by applying a UserDefinedConstraint containing the value of id-constraint-dtd-element as a parameter. id-constraint-dtd-element OBJECT IDENTIFIER ::= { id-constraint 3 } A UserDefinedConstraint in which an OBJECT IDENTIFIER with the value of id-constraint-dtd-element is used MUST satisfy all of the following conditions: a) there SHALL be three UserDefinedConstraintParameters, b) the first UserDefinedConstraintParameter SHALL be a Value of the OBJECT IDENTIFIER ASN.1 type and that Value SHALL be the same as id-constraint-dtd-element, c) the second UserDefinedConstraintParameter SHALL be a Value of the Legg & Prager Expires 15 December 2004 [Page 11] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 AnyURI ASN.1 type specifying the system identifier of an external DTD subset, d) the third UserDefinedConstraintParameter SHALL be a Value of the Name ASN.1 type specifying an element type declaration in the external DTD subset nominated by the second parameter. Example AnyType (CONSTRAINED BY { OBJECT IDENTIFIER: { iso(1) 2 36 79672281 xed(3) constraint(1) 3 }, AnyURI:"http://www.example.com/inventory", Name:"product" }) The Contained-DTD-Element parameterized type is defined so that DTD element type declarations can be more conveniently referenced. Contained-DTD-Element { AnyURI:schemaIdentity, Name:name } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-dtd-element, AnyURI:schemaIdentity, Name:name }) 7. Security Considerations Values of the AnyType type potentially hold the content of elements for which the Canonical XML [CXML] representation must be recoverable. Such recovery is needed for the verification of digital signatures. The rules governing the representation of the content of an element in an AnyType value are compatible with Canonical XML. Implementors must be careful not to introduce any further changes which would make it impossible to recover the Canonical XML representation. 8. Acknowledgements This document and the technology it describes are a product of a joint research project between Adacel Technologies Limited and Deakin University on leveraging existing directory technology to produce an XML-based directory service. 9. References 9.1. Normative References [BCP14] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Legg & Prager Expires 15 December 2004 [Page 12] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 [URI] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. [RXER] Legg, S. and D. Prager, "Robust XML Encoding Rules for ASN.1 Types", draft-legg-xed-rxer-xx.txt, a work in progress, June 2004. [X680] ITU-T Recommendation X.680 (07/02) | ISO/IEC 8824-1:2002, Information technology - Abstract Syntax Notation One (ASN.1): Specification of basic notation [X682] ITU-T Recommendation X.682 (07/02) | ISO/IEC 8824-3:2002, Information technology - Abstract Syntax Notation One (ASN.1): Constraint specification [X683] ITU-T Recommendation X.683 (07/02) | ISO/IEC 8824-4:2002, Information technology - Abstract Syntax Notation One (ASN.1): Parameterization of ASN.1 specifications [XML] Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, E. and F. Yergeau, "Extensible Markup Language (XML) 1.0 (Third Edition)", W3C Recommendation, http://www.w3.org/TR/2004/REC-xml-20040204, February 2004. [XMLNS] Bray, T., Hollander, D. and A. Layman, "Namespaces in XML", http://www.w3.org/TR/1999/REC-xml-names-19990114, January 1999. [ISET] Cowan, J. and R. Tobin, "XML Information Set", W3C Recommendation, http://www.w3.org/TR/2001/REC-xml- infoset-20011024, October 2001. [CXML] Boyer, J., "Canonical XML Version 1.0", W3C Recommendation, http://www.w3.org/TR/2001/REC-xml-c14n-20010315, March 2001. [XSD1] Thompson, H., Beech, D., Maloney, M. and N. Mendelsohn, "XML Schema Part 1: Structures", W3C Recommendation, http://www.w3.org/TR/2001/REC-xmlschema-1-20010502, May 2001. [RNG] Clark, J. and M. Makoto, "RELAX NG Tutorial", OASIS Committee Specification, http://www.oasis- open.org/committees/relax-ng/tutorial-20011203.html, December 2001. 9.2. Informative References Legg & Prager Expires 15 December 2004 [Page 13] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 [ASD] Legg, S. and D. Prager, "ASN.1 Schema: An XML Representation for ASN.1 Specifications", draft-legg-xed-asd-xx.txt, a work in progress, December 2003. Appendix A. ASN.1 for Schema Language Integration This appendix is normative. SchemaLanguageIntegration {iso(1) 2 36 79672281 xed(3) module(0) sli(1)} -- Copyright (C) The Internet Society (2004). This version of -- this ASN.1 module is part of RFC XXXX; see the RFC itself -- for full legal notices. DEFINITIONS IMPLICIT TAGS EXTENSIBILITY IMPLIED ::= BEGIN -- The non-parameterized types exported by this module belong -- to the namespace http://xmled.info/ns/ASN.1 . EXPORTS AnyType, AnyURI, NCName, Name, XML-Type{}, XML-Type-From-Schema{}, DTD-Type{}, Contained-XML-Element{}, Contained-XML-Element-From-Schema{} Contained-DTD-Element{}; AnyType ::= CHOICE { text [0] SEQUENCE { prolog [0] UTF8String (SIZE(1..MAX)) OPTIONAL, context [1] UTF8String (SIZE(1..MAX)) OPTIONAL, attributes [2] UTF8String (SIZE(1..MAX)) OPTIONAL, content [3] UTF8String (SIZE(1..MAX)) OPTIONAL } } AnyURI ::= UTF8String (CONSTRAINED BY { -- conforms to the format of a URI -- }) NCName ::= UTF8String (CONSTRAINED BY { -- conforms to the NCName production of -- Namespaces in XML -- }) Name ::= UTF8String (CONSTRAINED BY { -- conforms to the Name production of XML -- }) id-constraint OBJECT IDENTIFIER ::= { iso(1) 2 36 79672281 xed(3) constraint(1) } id-constraint-xml-type OBJECT IDENTIFIER ::= { id-constraint 0 } Legg & Prager Expires 15 December 2004 [Page 14] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 id-constraint-xml-element OBJECT IDENTIFIER ::= { id-constraint 1 } id-constraint-dtd-type OBJECT IDENTIFIER ::= { id-constraint 2 } id-constraint-dtd-element OBJECT IDENTIFIER ::= { id-constraint 3 } XML-Type { AnyURI:namespace, NCName:name } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-xml-type, AnyURI:namespace, NCName:name }) XML-Type-From-Schema { AnyURI:namespace, NCName:name, AnyURI:schemaIdentity } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-xml-type, AnyURI:namespace, NCName:name, AnyURI:schemaIdentity }) DTD-Type { AnyURI:schemaIdentity, Name:name } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-dtd-type, AnyURI:schemaIdentity, Name:name }) Contained-XML-Element { AnyURI:namespace, NCName:name } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-xml-element, AnyURI:namespace, NCName:name }) Contained-XML-Element-From-Schema { AnyURI:namespace, NCName:name, AnyURI:schemaIdentity } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-xml-element, AnyURI:namespace, NCName:name, AnyURI:schemaIdentity }) Contained-DTD-Element { AnyURI:schemaIdentity, Name:name } ::= AnyType (CONSTRAINED BY { OBJECT IDENTIFIER:id-constraint-dtd-element, AnyURI:schemaIdentity, Name:name }) END Authors' Addresses Dr. Steven Legg Adacel Technologies Ltd. 250 Bay Street Brighton, Victoria 3186 AUSTRALIA Phone: +61 3 8530 7710 Fax: +61 3 8530 7888 EMail: steven.legg@adacel.com.au Dr. Daniel Prager C/o Professor Lynn Batten Legg & Prager Expires 15 December 2004 [Page 15] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 Department of Computing and Mathematics Deakin University Geelong, Victoria 3217 AUSTRALIA EMail: dan@layabout.net EMail: lmbatten@deakin.edu.au Full Copyright Statement Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Changes in Draft 01 Legg & Prager Expires 15 December 2004 [Page 16] INTERNET-DRAFT XED: Schema Language Integration June 15, 2004 The Directory XML Encoding Rules (DXER) have been renamed to the Robust XML Encoding Rules (RXER). Changes in Draft 02 The AnyType ASN.1 type has been revised to be a CHOICE whose only alternative is the previously defined SEQUENCE type. The change will permit a future specification to more easily introduce alternative compact encodings for the content of elements. The mechanism for incorporating DTD element type declarations was not adequate to deal with DTDs using namespaces. The parameterized types DTD-Type and Contained-DTD-Element have been defined, along with Name, id-constraint-dtd-type and id-constraint-dtd-element, to allow element types in such DTDs to be referenced. See Section 5.2 and Section 6.2. Legg & Prager Expires 15 December 2004 [Page 17]