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> "Shortcutting" means that you only evaluate the first part of
> the expression if you can determine the result of the
> expression, correct? In XPath 1.0, 'and' and 'or' are shortcutting:
>
>
> I hadn't noticed that this changes in XPath 2.0 (it's not
> listed as one of the incompatibilities):
>
Yes - this should have been listed as an incompatibility.
This change was made because database systems need to use indexes to
evaluate boolean expressions. In a database system, if someone writes
colour=my-favourite-colour() and home-town="Wigan"
then if you have an index on home-town, you want to use it.
I've been thinking we might try to add something to XSLT that imposes
rules for XPath-in-XSLT that are stricter than the rules in XPath itself
to deal with such situations.
Michael Kay
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