Re: How to write (existential) predicates with maps/Wh

I'm having trouble understanding/reproducing this. Can you supply a complete
repro? (I.e., the source data that results in this error)

I've checked the message, and it's actually inaccurate: the offending item
might be a function/array/map rather than an atomic value.

Michael Kay
Saxonica

> On 11 Feb 2019, at 12:09, Martin Honnen martin.honnen@xxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> When using XPath 3.1 (e.g. in XSLT 3) on maps I have found that I have to
change my coding habit a bit when writing predicates that want to check the
existence of some nested map, while I hoped to be able to write e.g.
>
>  ?locations?*[?types?*[?name = 'foo']]
>
> to select all (map) members of the "locations" array that have a "types"
array with at least one (map) member having a property "name" with value "foo"
I get an error
>
> Effective boolean value is not defined for sequence starting with an atomic
value other than a boolean, number, or string
>
>
> So in contrast to my experience with writing predicates on XML it seems for
maps I have to explicitly use the "exists" function e.g.
>
>  ?locations?*[exists(?types?*[?name = 'foo'])]
>
> or a "some .. in" expression
>
>  ?locations?*[some $m in ?types?* satisfies $m?name = 'foo']
>
>
> Is there any more compact way to write such a check?
>
> What is the reason that the effective boolean value was not extended to give
true for a sequence with a map?