Issue raised: https://redmine.ogf.org/issues/309

Regards

Steve Hanson
IBM Integration Bus, Hursley, UK
Architect, IBM DFDL
Co-Chair, OGF DFDL Working Group
smh@uk.ibm.com
tel:+44-1962-815848
mob:+44-7717-378890

From: Mike Beckerle <mbeckerle.dfdl@gmail.com>
To: Steve Hanson/UK/IBM@IBMGB
Cc: DFDL-WG <dfdl-wg@ogf.org>
Date: 04/03/2016 14:59
Subject: Re: [DFDL-WG] Clarification for nil processing and zero length

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
tel:+44-1962-815848
mob:+44-7717-378890
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