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Simon St.Laurent wrote:
> I'm reasonably convinced that ASN.1 makes more sense than XML
> for a lot of projects where vendors are investing vast
> amounts of money and effort.
> If some aspect of ASN.1 can cover mixed content and open
> content models,
> I'm happy to welcome it to my regular list of
> XML schema languages. Otherwise, I'll be happy to continue
> promoting ASN.1 as an _alternative_ to XML, albeit one with
> ASN.1->XML->ASN.1 interoperability.
> (It's the anyXML->ASN.1->anyXML part that seems to remain a problem.)
If you are referring to "any XML" embedded in strongly typed data, the ASN.1
equivalent of XML Schema's content-model wildcard is a special Unicode
character string that can contain an XML element. This is defined as a
character string type with an [ANY-ELEMENT] encoding instruction. It is
possible to specify a namespace constraint as in XML Schema.
The only problem with this approach is that the string remains in textual
format (XML element) when the abstract value that contains it is re-encoded
in binary, so there is no space reduction for this particular data item.
Other approaches are possible and the ASN.1 committee will consider them in
the context of the forthcoming X.695 standard (ASN.1-based web services).