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 http://redmine.ogf.org/projects/editor-pubcom/boards/15.
Regards
Steve Hanson
Architect, IBM Data Format Description Language (DFDL)
Co-Chair, OGF
DFDL Working Group
IBM SWG, Hursley, UK
smh@uk.ibm.com
tel:+44-1962-815848
From:
"Cranford, Jonathan
W." <jcranford@mitre.org>
To:
"dfdl-wg@ogf.org"
<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
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)
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
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.]
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)
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