[xquery-talk] Is this a valid query?

[James Fuller]

+1 for

X => map:for-each(A, ?) meaning map:for-each(A, X)

Jim Fuller

On Sun, Jan 10, 2016 at 11:03 PM, Adam Retter <adam.retter at googlemail.com>
wrote:

> Thanks Mike, that is exactly the kinda detail I needed, and the bug
> report has many good comments.
>
> Personally I do like the idea and syntax from an XQuery authoring
> perspective of being able to do:
>
> X => map:for-each(A, ?) meaning map:for-each(A, X)
>
> However, I am not precious about it. So whichever way it is decided,
> as long as the spec defines, I will be both happy and informed ;-)
>
> Thanks again. Adam.
>
> On 10 January 2016 at 21:51, Michael Kay <mike at saxonica.com> wrote:
> > There's an open bug against the spec on the use of ?-placeholders in
> conjunction with the arrow operator.
> >
> > https://www.w3.org/Bugs/Public/show_bug.cgi?id=29346
> >
> > The grammar allows it, but the semantics have not been specified.
> >
> > My own view is that
> >
> > X => map:for-each(A, ?)
> >
> > should mean
> >
> > map:for-each(X, A, ?)
> >
> > which is an error because there are too many arguments.
> >
> > But we need to await the WG decision on this bug.
> >
> > Michael Kay
> > Saxonica
> >
> >
> >> On 10 Jan 2016, at 19:30, Adam Retter <adam.retter at googlemail.com>
> wrote:
> >>
> >> Given this valid XQuery (1):
> >>
> >> map:for-each(
> >>    map {
> >>        "a" : "1",
> >>        "b" : "2",
> >>        "c" : "3"
> >>    },
> >>    ?
> >> )(function($k, $v) {
> >>    "$k=" || $k
> >> })
> >>
> >> I am wondering, if rewriting it to the following form results in a
> >> valid query with the same execution result (2):
> >>
> >> function($k, $v) {
> >>    "$k=" || $k
> >> } =>
> >>    map:for-each(
> >>        map {
> >>            "a" : "1",
> >>            "b" : "2",
> >>            "c" : "3"
> >>        },
> >>        ?
> >>    )()
> >>
> >> In my mind it does, however I can't find a current implementation
> >> (eXist, BaseX, Saxon-EE) which will execute it, I guess this is due to
> >> evaluation order of the expressions (although I get parser errors).
> >>
> >> If I add some brackets to (2), to add precedence to the evaluation
> >> order so that I have (3):
> >>
> >> function($k, $v) {
> >>    "$k=" || $k
> >> } =>
> >>    (
> >>    map:for-each(
> >>        map {
> >>            "a" : "1",
> >>            "b" : "2",
> >>            "c" : "3"
> >>        },
> >>        ?
> >>    ))()
> >>
> >>
> >> Then it does seem to execute on BaseX and Saxon, but it feels like I
> >> shouldn't need to add the brackets and that (2) should work! Can
> >> someone add some comment/insight for me as to whether the XQuery spec
> >> requires these brackets to make the parse and execution correct?
> >> Somehow, I can't see it at the moment...
> >>
> >>
> >> Thanks Adam.
> >>
> >> --
> >> Adam Retter
> >>
> >> skype: adam.retter
> >> tweet: adamretter
> >> http://www.adamretter.org.uk
> >> _______________________________________________
> >> talk at x-query.com
> >> http://x-query.com/mailman/listinfo/talk
> >
> >
>
>
>
> --
> Adam Retter
>
> skype: adam.retter
> tweet: adamretter
> http://www.adamretter.org.uk
> _______________________________________________
> talk at x-query.com
> http://x-query.com/mailman/listinfo/talk
>
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