Determining schema language in xml-model (Was: Re: Minutes for XML Core WG telcon of 2010 January 27)

John Cowan wrote:

>> One can argue that it is quite strange to request access to resource in
>> order to determine its content. But in reality most documents will use
>> just one xml-model processing instruction so the cost of such check will
>> be small. 
> 
> I disagree, for the reasons given above.

More I think about it I think that you are right, there shoud be such
mechanism.

>> As to adding new dedicated attribute -- what was ideas about its
>> content? Namespace of the schema language used?
> 
> That seems plausible to me.

I was trying to come up with some good name for such attribute, but I
was not able to find name which I would like.

Then evil idea come to my mind. Lexical spaces for media types and URIs
do not overlap. So what about overloading type pseudo-attribute?

E.g.

Schema is in RELAX NG compact syntax:
<?xml-model href="schema.xxx" type="application/relax-ng-compact-syntax"?>

Schema language can't be determined, schema has to be fetched in order
to recognize it:
<?xml-model href="schema.xxx" type="application/xml"?>

Schema is written in W3C XML Schema, no need to network access:
<?xml-model href="schema.xxx" type="http://www.w3.org/2001/XMLSchema"?>

I still don't know whether this is good idea. Comments and suggestions
for name of separate attribute welcomed.

				Jirka

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