Bug 179737 The MeasureHandle should be able to provide data type info
We are now allow user input expression as measure expression. However this brings difficulties in determine the data type of a measure expression evaluation result. We need MeasureHandle to be enhanced to include the data type info. Please note that data type "any" is not accepted.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/writer/ModuleWriter.java
*            the partent structure that contains this structure
	 * @param memberName
	 *            the name of the list property
	 */
	private void writeStructure( IStructure struct, String memberName )
	{
		IStructureDefn structDefn = struct.getDefn( ).getMember( memberName )
				.getStructDefn( );
		assert struct instanceof Structure;
		IStructure memberStruct = (IStructure) ( (Structure) struct )
				.getLocalProperty( null, (PropertyDefn) struct.getDefn( )
						.getMember( memberName ) );
		if ( memberStruct == null )
			return;
		writer.conditionalStartElement( DesignSchemaConstants.STRUCTURE_TAG );
		writer.attribute( DesignSchemaConstants.NAME_ATTRIB, memberName );
		Iterator iter = structDefn.propertiesIterator( );
		while ( iter.hasNext( ) )
		{
			StructPropertyDefn strcutPropDefn = (StructPropertyDefn) iter
					.next( );
			
			
			writeMember( memberStruct, strcutPropDefn );
		}
		writer.endElement( );
	}
	/**
	 * Writes the structure list of the give property definition for given
	 * design element.