[xquery-talk] range implementations -- which is correct?
howardk at fatdog.com
Tue Jun 21 16:48:01 PDT 2005
Informative as always. Thank you!
Each of the three implementations is indeed correct for
( <a/>, <b/>, <c/> )[ position() = 1 to 2 ]
=> <a/>, <b/>
What's led to the revised view that EBV( atomic-sequence ) is an error?
> -----Original Message-----
> From: Michael Kay [mailto:mhk at mhk.me.uk]
> Sent: Tuesday, June 21, 2005 3:28 PM
> To: 'Howard Katz'; talk at xquery.com
> Subject: RE: [xquery-talk] range implementations -- which is correct?
> Saxon is correct against the most recent working draft: the
> effective boolean value of a sequence of several integers is
> now an error. Before the most recent draft, the EBV of any
> sequence containing more than one item was true; so Galax
> was correct. There was a prehistory in which "[1 to 2]" was
> recognized as some kind of custom syntax to extract a
> subsequence - at that stage (1 to 2) wasn't a
> general-purpose expression that could be composed with other
> expressions - so MarkLogic is reflecting that history.
> However, this had disappeared from the language before the
> May 2003 draft.
> Now try the correct syntax in each of the products:
> ( <a/>, <b/>, <c/> )[ position() = 1 to 2 ]
> Michael Kay
> > What's the result of invoking
> > ( <a/>, <b/>, <c/> )[ 1 to 2 ]
> > ----------------------------
> > MarkLogic 3.0 (May 2003 wd) returns
> > <a/>
> > <b/>
> > Galax 0.5.0 (Oct 2004 wd) returns
> > <a/>
> > <b/>
> > <c/>
> > Saxon 8.4 (Feb 2005 wd) returns
> > "Error: Effective boolean value is not defined for a sequence
> > of two or more items starting with an atomic value
> > The situation is made somewhat more confusing because each
> > implementation is implemented against a different version
> of the wd.
> > More precisely there are two questions:
> > (1) Which of the above results are correct (or incorrect) for the
> > version of the working draft against which they were
> implemented, and
> > (2) Which are correct (or incorrect) against the most
> recent working
> > draft of April 2005?
> > Howard
> > _______________________________________________
> > talk at xquery.com
> > http://xquery.com/mailman/listinfo/talk
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