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Re: Match Pattern Proposal

From: Erik Bruchez <ebruchez@orbeon.com>
Date: Thu, 02 Nov 2006 16:20:22 +0100
Message-ID: <454A0CB6.7000806@orbeon.com>
To: public-xml-processing-model-wg@w3.org

Norman Walsh wrote:
> We've discussed allowing XPath expressions of some form in five places:
> on choose/when, on parameters, on inputs, on viewport, and on for-each.
> 
> On choose/when and parameters, I think they have to be select
> expressions. And in any event, they don't select nodes so it's not
> quite the same thing.
> 
> On input, viewport, and for-each, it seems like we have three choices:
> 
> 1. Use 'select' semantics in every case.
> 2. Use 'match' semantics in every case.
> 3. Use 'select' semantics for some and 'match' for others.
> 
> I have a marginal preference for 1 or 2 on the basis that it's easier
> to explain to users. And I think select semantics are easier to explain
> and make more sense in the case of p:input, so I favor 1.
> 
> But Alex and Henry have both expressed a preference for match
> semantics at least on viewport and maybe on for-each.
> 
> What do others think?

Like Alex (Vernet) and Norm I am in favor of using select semantic. But 
I guess Alex (Vernet) and I get only one vote anyway ;-)

But I prefer select because:

* That's a single concept to explain to users
* Match patterns occur in fewer languages compared to select. I can
   never remember what's allowed in a match pattern ;-)
* Using match seems to introduce an unnecessary limitation
* Streaming can be done with match or select, in both cases it's a
   matter of detecting streamable vs. non-streamable expressions

-Erik

-- 
Orbeon - XForms Everywhere:
http://www.orbeon.com/blog/
Received on Thursday, 2 November 2006 15:22:38 GMT

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