RE: [w3c sml] [4632] Use of IRIs

Here is my proposal for this issue.

 

Proposal:

I propose that we should not refer to any specific URI/IRI RFC in the
SML and SML-IF specs. Instead, we should let the definition of sml:uri
be governed by the definition of xs:anyURI type defined in the schema
version we align to. 

 

Reasons:

1.    sml:uri is of type xs:anyURI as currently defined in the SML
schema. This type supports encoding international characters using a
well defined escaping scheme
(http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/datatypes.html#anyUR
I). SML instance documents can of course have internationalized content.
Thus internationalization is possible without any change to the spec as
it is defined today.



2.    We have decided to align SML 1.1 spec with XML schema 1.0 which is
aligned with URIs (RFC2396/2732).



3.    Most XML schema 1.0 processor implementations do not support IRIs.
This means that SML implementations that use an off-the-shelf schema 1.0
processor will need to provide additional implementation to support
IRIs. Implementing RFC 3987 (46 pages long) is non-trivial amount of
work. This is an unnecessary implementation burden given that
internationalization is already possible as described in #1.



4.    If we decide to align SML spec with XML schema 1.1 in a future
release, we will automatically get IRI functionality as schema 1.1 is
aligned with the IRI RFCs.



5.    The SML spec does not put any restrictions on additional reference
schemes that can be defined. If an application does not wish to use the
internationalization support already provided by sml:uri (xs:anyURI) for
reasons specific to its domain, it is free to define additional
scheme(s) to meet its needs without violating the SML 1.1 specification.

 

 

 

 

From: public-sml-request@w3.org [mailto:public-sml-request@w3.org] On
Behalf Of Pratul Dublish
Sent: Thursday, September 06, 2007 9:11 PM
To: public-sml@w3.org
Subject: RE: [w3c sml] [4632] Use of IRIs

 

Sorry, I meant to address this to Philippe and Kumar

 

From: public-sml-request@w3.org [mailto:public-sml-request@w3.org] On
Behalf Of Pratul Dublish
Sent: Thursday, September 06, 2007 8:47 PM
To: public-sml@w3.org
Subject: [w3c sml] [4632] Use of IRIs

 

Phil and Kumar

I am reluctant  to offer my suggestion as a proposal for resolving this
bug since I know that both of you are very passionate about the IRI/URI
issue. It will be great if one of you can make a proposal that we can
use to instigate consensus on this bug.

Thanks!
Pratul

 

From: Pratul Dublish 
Sent: Tuesday, September 04, 2007 1:38 PM
To: 'public-sml@w3.org'
Subject: Bug 4632 Use of IRIs

 

Here's a suggestion to resolve this bug.

 

Given the decision at Toronto F2F to require XML Schema 1.0 for SML 1.1
(i.e.,  XML Schema 1.0 must be supported, but implementations are not
prevented from using XML Schema 1.1), it may be better to continue using
URI as the interoperable reference scheme in SML IF since it aligns with
the definition of xs:anyURI in XML Schema 1.0 

 


3.2.17 anyURI


[Definition:]   anyURI represents a Uniform Resource Identifier
Reference (URI). An anyURI value can be absolute or relative, and may
have an optional fragment identifier (i.e., it may be a URI Reference).
This type should be used to specify the intention that the value
fulfills the role of a URI as defined by [RFC 2396]
<http://www.w3.org/TR/xmlschema-2/#RFC2396> , as amended by [RFC 2732]
<http://www.w3.org/TR/xmlschema-2/#RFC2732> . 

The mapping from anyURI values to URIs is as defined by the URI
reference escaping procedure defined in Section 5.4 Locator Attribute
<http://www.w3.org/TR/2001/REC-xlink-20010627/#link-locators>  of [XML
Linking Language] <http://www.w3.org/TR/xmlschema-2/#XLink>  (see also
Section 8 Character Encoding in URI References
<http://www.w3.org/TR/2001/WD-charmod-20010126/#sec-URIs>  of [Character
Model] <http://www.w3.org/TR/xmlschema-2/#CharMod> ). This means that a
wide range of internationalized resource identifiers can be specified
when an anyURI is called for, and still be understood as URIs per [RFC
2396] <http://www.w3.org/TR/xmlschema-2/#RFC2396> , as amended by [RFC
2732] <http://www.w3.org/TR/xmlschema-2/#RFC2732> , where appropriate to
identify resources. 

 

 

The above approach allows SML and SML IF implementations to leverage the
xs:anyURI support built into XML Schema 1.0 processors. Note that URI
reference escaping mechanism allows internationalized resource
identifiers to be specified as anyURI although the specification may not
be as elegant as that for IRIs.

 

If the WG still wants to pursue IRIs, then we'll need to define a new
datatype - say smlif:anyIRI - to capture the definition of xs:anyURI in
XML Schema 1.1. 

 


3.3.18 anyURI


[Definition:]   anyURI represents an Internationalized Resource
Identifier Reference (IRI).  An anyURI value can be absolute or
relative, and may have an optional fragment identifier (i.e., it may be
an IRI Reference).  This type should be used when the value fulfills the
role of an IRI, as defined in [RFC 3987]
<http://www.w3.org/TR/xmlschema11-2/#RFC3987>  or its successor(s) in
the IETF Standards Track. 

Note: IRIs may be used to locate resources or simply to identify them.
In the case where they are used to locate resources using a URI,
applications should use the mapping from anyURI values to URIs given by
the URI reference escaping procedure defined in Section 3.1 Mapping of
IRIs to URIs <http://www.ietf.org/rfc/rfc3987.txt>  of [RFC 3987]
<http://www.w3.org/TR/xmlschema11-2/#RFC3987>  or its successor(s) in
the IETF Standards Track.  This means that a wide range of
internationalized resource identifiers can be specified when an anyURI
is called for, and still be understood as URIs per [RFC 3986]
<http://www.w3.org/TR/xmlschema11-2/#RFC3986>  and its successor(s).

 

 

Most SML validators will need to add support for the above since the
above definition is not supported by XML Schema 1.0 processors.

 

 

Thanks!

Pratul