All, Attached are the first few implementation-specific features divided up between implementation-defined and implementation-dependent features. Three are implementation-defined and two are implementation-dependent. The intent is to add two definitions to the spec, similar to this snippet from the XProc specification (http://www.w3.org/TR/xproc/#conformance): Conformant processors must implement all of the features described in this specification except those that are explicitly identified as optional. Some aspects of processor behavior are not completely specified; those features are either implementation-dependent or implementation-defined. [Definition: An implementation-dependent feature is one where the implementation has discretion in how it is performed. Implementations are not required to document or explain how implementation-dependent features are performed.] [Definition: An implementation-defined feature is one where the implementation has discretion in how it is performed. Conformant implementations must document how implementation-defined features are performed.] I'm still working through the spec; I thought I'd send these off now to begin discussion. Fyi, Jonathan
-----Original Message-----
From: Steve Hanson [mailto:smh@uk.ibm.com]
Sent: Wednesday, September 18, 2013 3:30 AM
To: Cranford, Jonathan W.
Cc: dfdl-wg@ogf.org<mailto:dfdl-wg@ogf.org>; dfdl-wg-bounces@ogf.org<mailto:dfdl-wg-bounces@ogf.org>
Subject: Re: [DFDL-WG] action 224: add section for implementation defined limits
Jonathan
Thanks for citing that example. I have added a summary to the minutes of
yesterday's WG call.
Please go ahead and trawl the document for implementation defined/dependent
things.
Please also raise a public comment to track, at
Regards
Steve Hanson
Architect, IBM Data Format Description Language (DFDL)
Co-Chair, OGF DFDL Working Group <http://www.ogf.org/dfdl/>
IBM SWG, Hursley, UK
smh@uk.ibm.com<mailto:smh@uk.ibm.com> <mailto:smh@uk.ibm.com>
tel:+44-1962-815848
From: "Cranford, Jonathan W." <jcranford@mitre.org<mailto:jcranford@mitre.org>>
To: "dfdl-wg@ogf.org<mailto:dfdl-wg@ogf.org>" <dfdl-wg@ogf.org<mailto:dfdl-wg@ogf.org>>,
Date: 17/09/2013 16:11
Subject: [DFDL-WG] action 224: add section for implementation defined limits
Sent by: dfdl-wg-bounces@ogf.org<mailto:dfdl-wg-bounces@ogf.org>
________________________________
All,
Action item 224 was raised two weeks ago during the WG call.
224 Add section for implementation defined limits (All)
3/9: Several places in the spec cite this, should be grouped. Currently partially
listed in section
2.6.
Also note distinction between 'implementation defined' and 'implementation
dependent'. Check
spec for correct usage.
Resolve during public comment.
The action item was created based on a comment I made during the call, so I
thought it’d be good to provide an example of the distinction I was trying to
make.
The W3C XProc specification does a great job of differentiating between
implementation-defined and implementation-dependent features, with a
convenient list of each in the appendix.
Appendix A (http://www.w3.org/TR/xproc/#conformance
<http://www.w3.org/TR/xproc/#conformance> ) contains the following text.
Conformant processors must implement all of the features described in this
specification except those that are explicitly identified as optional.
Some aspects of processor behavior are not completely specified; those features
are either implementation-dependent <http://www.w3.org/TR/xproc/#dt-
implementation-dependent> or implementation-defined
[Definition: An implementation-dependent feature is one where the
implementation has discretion in how it is performed. Implementations are not
required to document or explain how implementation-dependent
<http://www.w3.org/TR/xproc/#dt-implementation-dependent> features are
performed.]
[Definition: An implementation-defined feature is one where the implementation
has discretion in how it is performed. Conformant implementations must
document how implementation-defined <http://www.w3.org/TR/xproc/#dt-
implementation-defined> features are performed.]
Section A.1 then lists all the implementation-defined features, and section A.2
lists all the implementation-dependent features.
I think the XProc spec provides a great example to follow on two counts. First, it
formally distinguishes between implementation-defined and implementation-
dependent features. The choice of terms isn’t nearly as important as the
distinction itself, of course: implementations must document how certain
features are implemented. In the DFDL realm, section 2.6 lists some
implementation limits which always constitute schema definition errors; surely
these are the types of details that must be documented by any DFDL
implementation. Using terminology such as “implementation-defined” and
“implementation-dependent” would flag these types of documentation
requirements for implementations within the specification.
Second, all the implementation-defined and implementation-dependent features
are listed in one place in the specification. I think doing the same in the DFDL
spec would provide a great resource for DFDL implementers.
Comments? If everyone agrees, I don’t mind taking the action to search through
the document looking for candidates for inclusion in such a list.
Sincerely,
--
Jonathan W. Cranford
Senior Information Systems Engineer
The MITRE Corporation (http://www.mitre.org <http://www.mitre.org/> )
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