Mike,
> One design approach, of course, is for functions to return () (or
> other special values such as NaN) rather than throwing errors. The
> disadvantage of this is that there is no opportunity to provide
> diagnostics indicating the nature of the failure.
I had the (probably baseless) impression that an "error object" would
be returned rather than thrown, with its value being an error message
or something, so you could do something like:
let $date := cast as xs:date('2002-02-29')
if ($date instance of error)
then concat('Invalid date: ', $date)
else ...
Is that not feasible?
Cheers,
Jeni
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Jeni Tennison
http://www.jenitennison.com/
