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   RE: [xml-dev] RE : [xml-dev] Comparison of Xml documents

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John Cowan wrote:
> Ed Day scripsit:
> > From a practical standpoint, an ASN.1 SET construct is roughly 
> > equivalent to an <xsd:all>.  Both allow the elements 
> defined within to 
> > be transmitted in any order.
> In a word, the difference is that SET says the transmission 
> order has no meaning, whereas xsd:all says the order might or 
> might not mean something.

In certain encoding rules (such as DER), the transmission order is fixed.
Therefore the statement that SET allows the elements to be transmitted in
any order is not a general statement about SET, but a statement about the
manner that SET is encoded in a specific set of encoding rules.

Transmission order of SET (when not fixed) is an example of what we call
"encoder's options".  Encoder's options exist for the convenience of
encoders, but carry no information at all.

Specifically, it would be a mistake to attribute any significance to the
order of elements for a SET in the XML encodings.  The abstract value is
**unordered**, so the application should not be exposed to the order.


> -- 
> John Cowan  jcowan@reutershealth.com  www.reutershealth.com  
www.ccil.org/~cowan Promises become binding when there is a meeting of the
minds and consideration is exchanged. So it was at King's Bench in common
law England; so it was under the common law in the American colonies; so it
was through more than two centuries of jurisprudence in this country; and so
it is today. 
       --_Specht v. Netscape_

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