ISSUE-15: Null datatype pattern as used by ASN.1 and others

ISSUE-15: Null datatype pattern as used by ASN.1 and others

http://www.w3.org/2005/06/tracker/databinding/issues/15

Raised by: Paul Downey
On product: Basic

"""
There is (apparently) no
equivalent in XSD to the ASN.1 NULL type.  The result is that users have to
make up their own and the results are often inconsistent.  For example, in
the CSTA specs, we see the following type definition:

  <xsd:annotation>
    <xsd:documentation>replacement for ASN.1 NULL type and helper type for
representation of the ASN.1 BIT STRING type</xsd:documentation>
  </xsd:annotation>
  <xsd:complexType name="Empty"/>

In XMPP, there is:

  <xs:simpleType name='empty'>
    <xs:restriction base='xs:string'>
      <xs:enumeration value=''/>
    </xs:restriction>
  </xs:simpleType>

It would be nice if a best practice schema pattern for representing empty
data could be published.

Regards,

Ed Day
Objective Systems, Inc.
"""

http://lists.w3.org/Archives/Public/public-xsd-databinding/2006Jan/0050.html