Re: [dss] anonymous types

[Juan Carlos Cruellas Ibarz <cruellas@ac.upc.es>]

Trevor

See below:
At 13:33 06/10/2003 -0700, Trevor Perrin wrote:
>
>Juan Carlos pointed out 2 things about the schema -
>
>  1) The <KeySelector> includes a <ds:Signature>, instead of being of type 
>ds:SignatureType.

Well, in fact this not what I tried to say. Sorry for the missunderstanding.
What I tried to say is that currently we have the following definition for 
the KeySelector element:

<xs:element name="KeySelector">
	<xs:complexType>
		<xs:sequence> 
			<xs:element ref="ds:KeyInfo"/> 
	</xs:sequence> 
	</xs:complexType> 
</xs:element> 

Doing that our KeySelector would be something like:

<KeySelector>
	<ds:KeyInfo>
		<!-- here the KeyInfo contents as defined in XMLDSIG -->
	</KeyInfo>
</KeySelector>

My point was that  if we changed the element definition to:

<xs:element name="KeySelector" type="ds:KeyInfoType"/>

our element would be:
<KeySelector>
	<!-- here the KeyInfo contents as defined in XMLDSIG 
	BUT WITHOUT THE EXTRA ENVELOPING TAGS
	<ds:KeyInfo> -->
</KeySelector>

I would say that this approach is first shorter, and second more
aligned with reusability of types...

Which means that we have an extra level of tags ... 
>  2) Elements are defined with "Anonymous Type Definitions" [1].
>
>As for (1), it seems more readable to re-use element names, so you can look 
>at an XML document and recognize "that's a ds:Transforms", "that's a 
>ds:KeyInfo", etc., without consulting the schema to figure out what type 
>everything is.
>
Well, I would say that this way of building structured information is very
redundant in the end, and this with a language as XML that it is very 
verbose by itself... In addition, generally speaking, if I want to completelly
understand a XML document in depth, I have to read the corresponding
schema, so that I can see not only what is in the XML document but
also what is NOT in the document but could be (optional elements), etc...
My point is that a deep understanding of a document demnads the 
knowledge of the schema. 

>As for (2), if we did it the Juan Carlos / XML-DSIG way, where every 
>element has a named Type, then other schemas could re-use our types without 
>re-using our names.  But none of the protocol pieces seem reusable anyways, 
>so named types don't seem to have much benefit.

I have read the message by Tim and I agree with him... sometimes in the 
same schema that one is defining there is a need for a named type reusage...
so I would say that at least with those items that could be reused outside
the protocol we should allow named types...

Juan Carlos




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