[DFDL-WG] Reducing the number of DFDL properties.

Mon Mar 2 11:44:26 CST 2009

If I recall, one reason for having the specialised elements was so that 
the content of the annotations could be more tightly validated by the 
schema-for-dfdl xsd.

However, the problem with the specialised annotations is that we do not 
provide them for all circumstances. For example, the spec allows me to use 
dfdl:sequence on an xs:sequence but not an xs:group reference to a global 
xs:group with compostion xs:sequence.  Nor does it allow me to use a 
specialised element on xs:simpleType or xs:restriction.  So as it stands, 
validation would not be fool-proof anyway.

I think we must either ditch specialisations, or mandate the use of 
specialisations on the corresponding schema objects. The latter is more 
workable now we have changed the scoping rules so that scoping of dfdl 
properties can only be done from complex type or schema level, as below. 
But it does mean that dfdl annotations are less flexible.

dfdl;defineFormat  =>  dfdl:format
xs:complexType => dfdl:format
xs:group => dfdl:format
xs:sequence or xs:group ref to a global group with xs:sequence => 
dfdl:sequence
xs:choice or xs:group ref to a global group with xs:choice  => dfdl:choice
xs:element or xs:element ref => dfdl:element
xs:any => dfdl:any
xs:simpleType, xs:restriction => dfdl:simpleType

In other words, you use dfdl:format when you are scoping properties, you 
must use specialised annotation for specific objects. 

Regards

Steve Hanson
Programming Model Architect
WebSphere Message Brokers
Hursley, UK
Internet: smh at uk.ibm.com
Phone (+44)/(0) 1962-815848

Suman Kalia <kalia at ca.ibm.com> 
Sent by: dfdl-wg-bounces at ogf.org
02/03/2009 16:25

To
"Dave Glick" <dglick at dracorp.com>
cc
dfdl-wg at ogf.org, dfdl-wg-bounces at ogf.org
Subject
Re: [DFDL-WG] Reducing the number of DFDL properties.

I am not sure what kind of confusion or redundancy is caused by these 
specialized annotations.  In the absence of these specialized annotations, 
you will have to go through plethora of  annotations and determine which 
ones are applicable for sequence , choice, all, elements etc.. 

The danger is we don't have these levels of abstractions, then number of 
folks (specifically implementers) would build them anyway and then we will 
have to contend with incompatible abstractions.. 

Suman Kalia
IBM Toronto Lab
WMB Toolkit Architect and Development Lead
WebSphere Business Integration Application Connectivity Tools 

http://www.ibm.com/developerworks/websphere/zones/businessintegration/wmb.html

Tel : 905-413-3923  T/L  969-3923
Fax : 905-413-4850 T/L  969-4850
Internet ID : kalia at ca.ibm.com 

From: 
"Dave Glick" <dglick at dracorp.com> 
To: 
"Alan Powell" <alan_powell at uk.ibm.com>, <mbeckerle.dfdl at gmail.com> 
Cc: 
dfdl-wg at ogf.org 
Date: 
03/02/2009 11:16 AM 
Subject: 
Re: [DFDL-WG] Reducing the number of DFDL properties.

Alan/Mike, 

I agree with this ? one of my complaints with v033 was that these 
specialized annotation elements just added confusion and redundancy. 

Dave 

---
David Glick  |  dglick at dracorp.com  |  703.299.0700 x212
Data Research and Analysis Corp.  |  www.dracorp.com 

From: dfdl-wg-bounces at ogf.org [mailto:dfdl-wg-bounces at ogf.org] On Behalf 
Of Alan Powell
Sent: Monday, March 02, 2009 11:03 AM
To: mbeckerle.dfdl at gmail.com
Cc: dfdl-wg at ogf.org
Subject: Re: [DFDL-WG] Reducing the number of DFDL properties. 

Mike 

Thanks 

Can I also suggest dropping the dfdl:sequence, dfdl:choice, dfdl:element 
and dfdl:any specialized annotations and just have dfdl:format. 

Alan Powell

MP 211, IBM UK Labs, Hursley,  Winchester, SO21 2JN, England
Notes Id: Alan Powell/UK/IBM     email: alan_powell at uk.ibm.com 
Tel: +44 (0)1962 815073                  Fax: +44 (0)1962 816898

From: 
"Mike Beckerle" <mbeckerle.dfdl at gmail.com> 
To: 
Alan Powell/UK/IBM at IBMGB 
Cc: 
<dfdl-wg at ogf.org> 
Date: 
28/02/2009 19:38 
Subject: 
RE: Reducing the number of DFDL properties.

If a property is redundant, I'm in favor of dropping it. 

If a property adds generality that we don't have a use case for, I'm in 
favor of dropping it. 

I am happy to drop type substitution from v1.0. It's a convenience that 
can be achieved a different way. 

E.g., if you really want "float" to mean "float in my particular binary 
representation", then just put a type definition with DFDL annotations in 
a different namespace, and when you write your DFDL schema, arrange for 
the default namespace to pick it up from your namespace, and not xs:float. 

<xs:element name="myElement" type="float"/> <!-- float here is 
myNamespace:float which can have DFDL annotations on it --> 
<xs:element name="anotherElem" type="xs:float"/> <!-- explicitly xs:float 
without further adornment --> 

If you want the XSD unadorned "float" type, be explicit and use 
"xs:float". Voila - no loss of flexibility, equal textual convenience. 

I think that would satisfy the community that really wanted very compact 
"slideware acceptable" schemas. This is the same group that wants 
short-form annotations as well. 
Mike Beckerle | OGF DFDL WG Co-Chair | CTO | Oco, Inc.
Tel:  781-810-2100  | 100 Fifth Ave., 4th Floor, Waltham MA 02451 | 
mbeckerle.dfdl at gmail.com 

From: Alan Powell [mailto:alan_powell at uk.ibm.com] 
Sent: Thursday, February 26, 2009 12:22 PM
To: mbeckerle.dfdl at gmail.com
Cc: dfdl-wg at ogf.org
Subject: Reducing the number of DFDL properties.

Mike 

A number of people at IBM have become concerned at the number of 
properties in DFDL and have identified a number of 'usability' properties 
that could be dropped. They feel that we should be simplifying the 
properties wherever possible and not introducing multiple ways of doing 
the same function without very good reason. 

The following are offered for consideration. 
1.        lengthKind='nullterminated'
This is just shorthand for lengthKind=delimited and terminator='%Null'. It 
was felt this this is not even the most common terminator so why have a 
special case? 
2.        trimKind
It is felt that there aren't any cases when you would want to pad but not 
trim and vice versa so make padKind control both. 
3.        typeSubstitution.
Is this needed in DFDL v1? 

Can you consider these before the call next week 

Alan Powell

MP 211, IBM UK Labs, Hursley,  Winchester, SO21 2JN, England
Notes Id: Alan Powell/UK/IBM     email: alan_powell at uk.ibm.com 
Tel: +44 (0)1962 815073                  Fax: +44 (0)1962 816898

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 

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