Proposal from the i18n-core wg for changes of anyURI

Dear XML Schema working group,

This is a proposals for changes of the datatype anyURI, as described by 
xml schema (cf. It is send 
on behalf of the i18n-core wg.

The i18n-core-wg proposes an update of the datatype anyURI which is 
defined in the current version of XML Schema part 2, cf. Currently the 
mapping from anyURI  values to URIs is defined in terms of the XLINK 
specification, cf. . We think 
that anyURI should refer to the specification of Internationalized 
Resource Identifiers (IRIs) instead, cf. The IRI specification has achieved a 
stable status. It is a specification of how to expand the set of 
characters in URIs from a subset of US-ASCII to the Universal Character 
Set (Unicode/ISO 10646). W3C has announced to support the IRI 
specification, so we propose its application for anyURI. Our proposal 
for anyURI consists of 4 points:

(1) anyURI should refer to sec. 3.1 of the IRI-spec, instead of XLINK. 
This is important for example because of the normalization requirements 
as described in the IRI specification: if a legacy-encoding is not 
normalized before mapping from anyURI to URIs, the result might be 
different from the normalized case. The IRI specification gives an 
example for such a legacy-encoding from Vietnamese encoded as 
windows-1258, cf. also sec. 3.1. The normalization problem is only an 
example of many other important details which are discussed in the IRI 
(2) Any reference to URI should be updated from RFC 2396 to RFC 3987. 
For domain names, anyURI should refer to the IDN-part of the ABNF of the 
IRI-spec, cf. sec. 2.2 of the IRI-spec. This will allow access to 
internationalized domain names.
(3) The definition of anyURI may want to point to the following 
paragraph from section 3.1 of the IRI specification:
"Systems accepting IRIs MAY also deal with the printable characters in 
US-ASCII that are not allowed in URIs, namely "<", ">", '"', space, "{", 
"}", "|", "\", "^", and "`", in step 2 above.  If these characters are 
found but are not converted, then the conversion SHOULD fail.  Please 
note that the number sign ("#"), the percent sign ("%"), and the square 
bracket characters ("[", "]") are not part of the above list and MUST 
NOT be converted.  Protocols and formats that have used earlier 
definitions of IRIs including these characters MAY require 
percent-encoding of these characters as a preprocessing step to extract 
the actual IRI from a given field. This preprocessing MAY also be used 
by applications allowing the user to enter an IRI."
(4) an editorial issue: the reference from anyURI to section 8 of the 
old version of the "character model for the world wide web" 
specification should be changed to the new charmod-resid specification, 

Best regards,

Felix Sasaki.

Received on Monday, 4 April 2005 08:35:41 UTC