I think we will have to go back to the XPath function spec and see what
that says. https://www.w3.org/TR/xpath-functions-31/#func-count.
If fn:count(.) returns the same as dfdl:occursIndex() then what is the
point of the latter? If I recall it was added to allow a reference from
one array to the same occurrence in another array, eg,
dfdl:length="{/doc/lengths[dfdl:occursIndex(.)]}"
Regards
Steve Hanson
IBM Hybrid Integration, Hursley, UK
Architect, IBM DFDL
Co-Chair, OGF DFDL Working Group
smh@uk.ibm.com
tel:+44-1962-815848
mob:+44-7717-378890
Note: I work Tuesday to Friday
From: Mike Beckerle
To: DFDL-WG
Date: 08/10/2019 17:06
Subject: [DFDL-WG] recent puzzlers on fn:count and fn:exists
Sent by: "dfdl-wg"
These questions came up recently from daffodil users. I know what Daffodil
will return here, but the spec is not clear to me as to whether that's the
right answer or is even defined.
Can an array count itself? Like this:
xs:annotation
http://www.ogf.org/dfdl/">
The above can be reformulated by calling instead of fn:count,
dfdl:occursIndex(), and that's definitely well defined in this case. But
what does fn:count return in this case? Daffodil will return the same
value
as the occursIndex, because it will have speculatively attached the array
element to the infoset at the time the fn:count function is being
evaluated. But I don't know if that is the right answer or if we should
simply say that fn:count is not defined in this case.
Similarly, does an array element exist when it is being parsed?
xs:annotation
http://www.ogf.org/dfdl/">
Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
www.tresys.com
Please note: Contributions to the DFDL Workgroup's email discussions are
subject to the OGF Intellectual Property Policy
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