My read of 13.16 says that for nilKind 'literalValue' and textual representation, WSP* is already allowed for simple types.  So I think nilValue="%WSP*;" should work and match empty string.

Delimiters have qualifiers on ES alone and WSP* alone e.g., for separator: "However, the WSP* entity cannot appear on its own as one of the string literals in the list when determining the length of a component by scanning for delimiters, , and it is a schema definition error otherwise. delimiters"

(Note the fragment at the end of that sentence. That's a spec. bug)

But I see no such stipulation for nilValue.


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


On Fri, Mar 4, 2016 at 6:35 AM, Steve Hanson <smh@uk.ibm.com> wrote:
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@uk.ibm.com
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