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Re: Nasty XPath expressions

• To: Kelvin Yeow <whyeow@c...>
• Subject: Re: Nasty XPath expressions
• From: bob mcwhirter <bob@w...>
• Date: Thu, 13 Dec 2001 08:49:50 -0500 (EST)
• Cc: xml-dev@l...
• In-reply-to: <Pine.SUN.3.96.1011213023431.6142C-100000@valdes>

On Thu, 13 Dec 2001, Kelvin Yeow wrote:

> I wonder what XPath expressions would cause an "XPath processor" to sweat?
> Any "XPath processor" developer out there?

Howdy, I'm Bob, one of the developers of Jaxen (http://jaxen.org/), a
'universal' XPath engine for Java.

The biggest issue we've had (it's Today's Big Issue) is regarding 
document-ordering when using a union expression.

	$foo/bar | $cheese/melty

XPath says that nodes should be returned in 'document order', which
becomes a non-trivial in the case of some expressions involving
the union operator.  One developer has a solution, but it is of
O(tree-size) complexity.  Do that against a 30mb document, and
suddenly XPath isn't nearly as attractive.

Long/complex xpaths, or xpaths involving '//' and such aren't really
that hairy.

	-bob

• Follow-Ups:
  • RE: Nasty XPath expressions
    • From: "Michael Kay" <michael.h.kay@n...>
  • Re: Nasty XPath expressions
    • From: "Evan Lenz" <elenz@x...>

• References:
  • Nasty XPath expressions
    • From: Kelvin Yeow <whyeow@c...>

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