[DFDL-WG] Clarification for nil processing and zero length

[Steve Hanson]

The DFDL 1.0 spec current says:

9.3.2.1 Simple element
If the result is length zero as described above, the representation is 
then established by checking, in order for:
1.      nil representation (if %ES; is a literal nil value). 
2.      empty representation.
3.      normal representation (xs:string or xs:hexBinary only)
4.      absent representation (if none of the prior representations 
apply). 

But should bullet 1 be:

1. nil representation (if either %ES; or %WSP*; on its own is a literal 
nil value). 

I added a test to IBM DFDL and found that setting 
dfdl:nilKind="literalValue" & dfdl:nilValue="%WSP*;" did not match an 
element value of empty string. That surprised me, and I think the IBM DFDL 
code is strictly implementing bullet 1.  Using "%WSP*;" is useful for 
allowing zero or more white space to mean <nil>. I could use "%WSP+; %ES" 
to achieve the same goal but I'm not sure that was the intent here. 

Quick response appreciated.

Regards
 
Steve Hanson
IBM Integration Bus, Hursley, UK
Architect, IBM DFDL
Co-Chair, OGF DFDL Working Group
smh at uk.ibm.com
tel:+44-1962-815848
mob:+44-7717-378890
Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.ogf.org/pipermail/dfdl-wg/attachments/20160304/70b715ef/attachment.html>