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Re: Quick Xpath

• To: bob mcwhirter <bob@w...>
• Subject: Re: Quick Xpath
• From: Uche Ogbuji <uche.ogbuji@f...>
• Date: Wed, 17 Jul 2002 21:13:51 -0600
• Cc: Jeni Tennison <jeni@j...>, xml-dev@l...
• In-reply-to: Message from bob mcwhirter <bob@w...> of "Wed, 17 Jul 2002 19:21:22 EDT." <Pine.LNX.3.96.1020717192021.21107D-100000@e...>
• Sender: uche.ogbuji@f...

> > > Technically, I think we're compliant, but it sure can annoy the
> > > user. ;)
> > 
> > It would certainly be annoying if, for example, (//foo)[4] didn't
> > return the 4th foo element in the document, because it wouldn't be
> > compliant.
> > 
> > In the XPath 1.0 spec it states that a Predicate on an expression (as
> > here) filters the node-set with respect to the child axis [1]. The
> > child axis is a forward axis, so the nodes must be arranged in
> > document order when assessing their position [2].
> 
> Howsabout given:
> 
> 	(//foo | //bar)[4]
> 
> Would that be the 4th occurrence of either foo or bar, in document 
> order?  That's just an implementational nightmare.

I don't see it as an implementation nightmare at all, having implemented 
XPath.  Yes it would probably be a nightmare for the user, but so would:

10: PRINT "I'm cool"
20: GOTO 10

If the user wants to do something silly, it's not XPath's business to get in 
his way.


-- 
Uche Ogbuji                                    Fourthought, Inc.
http://uche.ogbuji.net    http://4Suite.org    http://fourthought.com
Track chair, XML/Web Services One Boston: http://www.xmlconference.com/
The many heads of XML modeling - http://adtmag.com/article.asp?id=6393
Will XML live up to its promise? - http://www-106.ibm.com/developerworks/xml/li
brary/x-think11.html

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