When I started this I was fairly neutral about it, but I've now used
Javascript enough to form a strong distaste for weak typing.
What about Typescript?
Cheers,
Dimitre Novatchev
On Tue, Feb 12, 2019 at 8:41 AM Michael Kay mike(_at_)saxonica(_dot_)com
<xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> wrote:
I've improved the error message so it now says:
FORG0006: Effective boolean value is not defined for sequence starting with a
map
(map{"name":"foo", })
The reason for the problem:
parse-json($json)?locations?*[?types?*[?name = 'foo']]"
locations?* => a sequence of maps
?types => a sequence of arrays
?types?* => a sequence of maps
So the value of the outer predicate is a sequence of zero-or-more maps, and
you can't get the EBV of a map.
Created W3C test case predicate-056.
What is the reason that the effective boolean value was not extended to give
true for a sequence with a map?
Sentiment in the WGs slowly moved away from weak typing and implicit
conversion over the years that followed XPath 1.0 (Getting arrays to be
atomizable was a bit of a battle). I think the richer the type system
becomes, the more useful it is to have errors rather than implicit
conversions. I saw a horrible one last week in which someone did
<xsl:with-param>2</xsl:with-param> and then tried to use the value as a
"numeric" predicate, not realising it was actually a node.
When I started this I was fairly neutral about it, but I've now used
Javascript enough to form a strong distaste for weak typing.
Michael Kay
Saxonica
On 12 Feb 2019, at 16:07, Martin Honnen
martin(_dot_)honnen(_at_)gmx(_dot_)de
<xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> wrote:
On 12.02.2019 15:40, Michael Kay mike(_at_)saxonica(_dot_)com wrote:
I'm having trouble understanding/reproducing this. Can you supply a
complete repro? (I.e., the source data that results in this error)
The example JSON is e.g.
{
"locations" : [
{
"id" : "i1",
"types" : [
{
"name" : "foo"
},
{
"name" : "bar"
}
]
},
{
"id" : "i2",
"types" : [
{
"name" : "baz"
}
]
},
{
"id" : "i3",
"types" : [
{
"name" : "foo"
},
{
"name" : "baz"
}
]
}
]
}
If you pass it to the parse-json function and use the result as the context
item to the three XPath expressions I have posted then the first one gives
that error while the other two return two maps.
A complete repro in XSLT is
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="#all"
version="3.0">
<xsl:output method="adaptive"/>
<xsl:param name="json" as="xs:string">
{
"locations" : [
{
"id" : "i1",
"types" : [
{
"name" : "foo"
},
{
"name" : "bar"
}
]
},
{
"id" : "i2",
"types" : [
{
"name" : "baz"
}
]
},
{
"id" : "i3",
"types" : [
{
"name" : "foo"
},
{
"name" : "baz"
}
]
}
]
}
</xsl:param>
<xsl:template match="/" name="xsl:initial-template">
<xsl:sequence select="parse-json($json)?locations?*[?types?*[?name =
'foo']]"/>
</xsl:template>
</xsl:stylesheet>
On 11 Feb 2019, at 12:09, Martin Honnen
martin(_dot_)honnen(_at_)gmx(_dot_)de
<xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> 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?
--~----------------------------------------------------------------
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
EasyUnsubscribe: http://lists.mulberrytech.com/unsub/xsl-list/1167547
or by email: xsl-list-unsub(_at_)lists(_dot_)mulberrytech(_dot_)com
--~--