Folks,

I wanted to remind everyone the purpose of dfdl:sequence and the other specialized annotations.

The point of these is to allow a XSD for dfdl annotations to provide some value in the following way:

Get an XSD-aware XML Editor (e.g., Altova XML Spy).
Plug into it the XSD for dfdl annotations.
Start editing a DFDL Schema.
When you type dfdl:sequence instead of dfdl:format, based on the schema (for DFDL annoataions) information, Altova XML Spy will give you pulldown lists and graphical prompting which will show you only the relevant properties.
If you type dfdl:format you get all the properties, little help for narrowing down the list.

The whole point: cheap and easy tooling to help author DFDL schemas.

This is why these were moved to a later section of the document. They're not needed for the DFDL language per se. They're just there to enable this tooling. Symantically, they mean exactly what dfdl:format means. We could just completely avoid mention of them until that point in the spec., which would perhaps remove the issues of confusion as mentioned by Dave Glick.

Here's the reason why we might want to remove them anyway: Too many properties are applicable to these things. Since everything can have text represetnation, and text representation requires a whole bunch of properties, you get a long list of properties for a dfdl:sequence. Not a short list of separator/terminator type properties only. Every property that affects text and character sets applies. Given this, the value of these things gets somewhat diluted.

I can go either way with this particular item. At minimum we should reserve all symbols in the dfdl namespace. I think Suman is right that if we don't specify these, then people will create them in various non-standard ways.

From: dfdl-wg-bounces@ogf.org [mailto:dfdl-wg-bounces@ogf.org] On Behalf Of Steve Hanson
Sent: Monday, March 02, 2009 6:45 PM
To: Suman Kalia
Cc: dfdl-wg@ogf.org
Subject: Re: [DFDL-WG] Reducing the number of DFDL properties.

Suman

A DFDL annotation on a group reference overrides a DFDL annotation on the content of the model group (ie, sequence, choice), not a DFDL annotation on the global group. It allows you to override the sequence/choice properties at point of use. The DFDL annotation on a global group is like that on a complex type - it is a scoping construct only.

Regards

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

Suman Kalia <kalia@ca.ibm.com>

02/03/2009 22:02

To	Steve Hanson/UK/IBM@IBMGB
cc	dfdl-wg@ogf.org, "Dave Glick" <dglick@dracorp.com>
Subject	Re: [DFDL-WG] Reducing the number of DFDL properties.

I can see where you are coming from and I agree with most of your proposal except putting dfdl:sequence, dfdl:choice , dfdl:all on group references as it does not give the right optics.. From consistency point of view, the references (group and element references) should have the equivalent/same set of annotations that can appear on the referenced artifacts.

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@ca.ibm.com

From:	Steve Hanson <smh@uk.ibm.com>
To:	Suman Kalia/Toronto/IBM@IBMCA
Cc:	dfdl-wg@ogf.org, "Dave Glick" <dglick@dracorp.com>
Date:	03/02/2009 12:45 PM
Subject:	Re: [DFDL-WG] Reducing the number of DFDL properties.

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@uk.ibm.com
Phone (+44)/(0) 1962-815848

Suman Kalia <kalia@ca.ibm.com>
Sent by: dfdl-wg-bounces@ogf.org

02/03/2009 16:25

To	"Dave Glick" <dglick@dracorp.com>
cc	dfdl-wg@ogf.org, dfdl-wg-bounces@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@ca.ibm.com

From:	"Dave Glick" <dglick@dracorp.com>
To:	"Alan Powell" <alan_powell@uk.ibm.com>, <mbeckerle.dfdl@gmail.com>
Cc:	dfdl-wg@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@dracorp.com | 703.299.0700 x212
Data Research and Analysis Corp. | www.dracorp.com

From: dfdl-wg-bounces@ogf.org [mailto:dfdl-wg-bounces@ogf.org] On Behalf Of Alan Powell
Sent: Monday, March 02, 2009 11:03 AM
To: mbeckerle.dfdl@gmail.com
Cc: dfdl-wg@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@uk.ibm.com
Tel: +44 (0)1962 815073 Fax: +44 (0)1962 816898

From: "Mike Beckerle" <mbeckerle.dfdl@gmail.com>
To: Alan Powell/UK/IBM@IBMGB
Cc: <dfdl-wg@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"/> 
<xs:element name="anotherElem" type="xs:float"/> 

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.

From: Alan Powell [mailto:alan_powell@uk.ibm.com]
Sent: Thursday, February 26, 2009 12:22 PM
To: mbeckerle.dfdl@gmail.com
Cc: dfdl-wg@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@uk.ibm.com
Tel: +44 (0)1962 815073 Fax: +44 (0)1962 816898

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