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Differences from draft-legg-xed-glue-01.txt
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
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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
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Distribution of this document is unlimited. Technical discussion of
this document should take place on the XED developers mailing list
<xeddev@adacel.com>. Please send editorial comments directly to the
editor <steven.legg@adacel.com.au>.
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
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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
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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,
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- 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:
<?xml version='1.0'?>
<!DOCTYPE root [
<!ENTITY TRUE 'true'>
]>
<root xmlns:ns="http://www.example.com/SLI">
<example ns:foo="1" bar="0">
<this>&TRUE;</this>
<that/>
</example>
</root>
The AnyType value corresponding to the content of the <example>
element is, in ASN.1 value notation [X680]:
text:{
prolog { "<?xml version='1.0'?>", lf,
"<!DOCTYPE root [", lf
" <!ENTITY TRUE 'true'>", lf
"]>", lf },
context "xmlns:ns=""http://www.example.com/SLI""",
attributes " ns:foo=""1"" bar=""0""",
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content { lf,
" <this>&TRUE;</this>", lf,
" <that/>", lf, " " }
}
The following AnyType value is also an acceptable representation
of the content of the <example> element:
text:{
context "xmlns:ns=""http://www.example.com/SLI""",
attributes "bar=""0"" ns:foo=""1""",
content { lf,
" <this>true</this>", lf,
" <that/>", 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
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{ -- 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,
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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:
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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:
<type xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<sequenceOf/>
<element name="number" type="xsd:decimal"/>
</sequenceOf>
</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
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with a system identifier of "http://www.example.com/inventory":
<?xml version='1.0'?>
<!ELEMENT product EMPTY>
<!ATTLIST product
name CDATA #IMPLIED
partNumber CDATA #REQUIRED
quantity CDATA #REQUIRED >
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:
<inventoryItem name="hammer" partNumber="1543" quantity="29"/>
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).
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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.
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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
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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.
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[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
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[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 }
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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.
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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]
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