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RE: Is Anyone Interested In XPath 2.0 Use Cases or Requiremen

• To: "'Dare Obasanjo'" <dareo@m...>,"'Uche Ogbuji'" <uche.ogbuji@f...>
• Subject: RE: Is Anyone Interested In XPath 2.0 Use Cases or Requirements?
• From: "Michael Kay" <michael.h.kay@n...>
• Date: Mon, 8 Jul 2002 11:09:49 +0100
• Cc: <xml-dev@l...>
• Importance: Normal
• In-reply-to: <8BD7226E07DDFF49AF5EF4030ACE0B7E06621DAF@r...>
• Reply-to: <michael.h.kay@n...>

> >> 4.) Lack of value comparators for nodesets
> >I'm not clear on what you mean here, and a brief read of your full 
> >article didn't help me.  Can you clarify?  An example, perhaps?
> 
> There is no mechanism to perform comparisons of node sets for 
> equality in the same manner one would for mathematical sets. 
> For instance I can't say a node-set containing (A, B, C) is 
> equivalent to a nodeset containing (B, C, A)

You can, actually. It might not be elegant, but

  count($A|$B) = count($A) and count($A|$B) = count($B)

does the job (assuming by "equivalence" you meant identity-based equivalence). 

Generally-speaking, XPath 1.0 programming is a bit like reduced-instruction-set computing; there is not always an obvious solution, but there is usually a solution (the exception being general joins, and hence operations like "distinct").

Michael Kay
Software AG
home: Michael.H.Kay@n...
work: Michael.Kay@s... 

• References:
  • RE: Is Anyone Interested In XPath 2.0 Use Cases or Requirements?
    • From: "Dare Obasanjo" <dareo@m...>

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