Suman Whatever you come up with needs to treat dfdl:defineVariableBlock (or whatever we call it) the same as other 'global' DFDL annotations like dfdl:defineTextNumberFormat and dfdl:defineTextCalendarFormat. Currently those are only allowed at schema level. So are you proposing that all these 'global' annotations can also live inside a dfdl:defineFormat annotation? You say best practice is to constrain the variable block locally. Please can you state the reasons why this is. Regards Steve Hanson Programming Model Architect WebSphere Message Brokers Hursley, UK Internet: smh@uk.ibm.com Phone (+44)/(0) 1962-815848 Suman Kalia/Toronto/IBM@IBMCA 16/06/2009 16:44 To Alan Powell/UK/IBM@IBMGB, Steve Hanson/UK/IBM@IBMGB cc dfdl-wg@ogf.org, dfdl-wg-bounces@ogf.org Subject Variable definitions in the defineFormat block Alan/Steve - Changes after our meeting this morning (June 16, 2009) Define a variable format block just like we define textNumberFormat. The variable block could be at schema level but preferably should be defined within the defineFormat definition so that variables are scoped to format definition and do not pollute the schema namespace.. Variable block is referenced from dfdl:format annotation just like textNumberFormat block is referenced through textNumberFormatRef annotation. It addresses the problem hilited today in the meeting related to semantics of dfdl:ref="myFormat" annotation on a xsd constructs. The net effect of this annotation is as if the dfdl:format annotation (along with the attribute settings) is specified explicitly on the xsd construct. By providing a level of indirection and referencing variable block through varRef annotations, we have permitted visibility to variables but not to the definition of variables. Excerpts from MyEnvelopeFormat.xsd - attached for perusal.. Also attached is the [attachment "dfdl_variables_example_update.zip" deleted by Steve Hanson/UK/IBM] PI for the example ( see updated xsd files under the folder enveloper_skk) <xsd:annotation> <xsd:appinfo source="http://dataformat.org/"> <dfdl:defineFormat name="MyEnvelopeFormat" baseFormat="dfdlDefaultFormat:defaultFormat" > <!-- statically override properties specific to the envelope wrapped messages --> <dfdl:format byteOrder="big-Endian" varRef="./MyEnvelopeFormatVariables"/> <!-- Identify variables for processing the messages wrapped in an envelope i.e. the set of properties values that I need to take from input data and dynamically set the values of dfdl properties during the processing of the message. Assumption: Names of variables defined in the format are unique --> <!-- Define the variables needed for the format locally in the format block --> <!-- They could also be defined at the schema level and referenced through varRef --> <!-- as its definition is QName just like textFormatBlock or numberFormatBlock --> <!-- Best practice would be to constraint the variable block locally --> <dfdl:defineVariableBlock name="MyEnvelopeFormatVariables"> <dfdl:defineVariable name="sep" type= "string" /> <dfdl:defineVariable name="enc" type= "string" /> <dfdl:defineVariable name= "outputDirPathSep" type="string" default="/" use="output" /> <dfdl:defineVariable name="outputMsgKind" type="string" use="output" /> <dfdl:defineVariable name="inputMsgKind" type="string" use="input" /> </dfdl:defineVariableBlock> </dfdl:defineFormat> </xsd:appinfo> </xsd:annotation> 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.ht... Tel : 905-413-3923 T/L 969-3923 Fax : 905-413-4850 T/L 969-4850 Internet ID : kalia@ca.ibm.com 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