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

Sat Feb 28 13:38:06 CST 2009

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. 

  _____  

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

  _____  

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