Bug 132515 Expression like "Toltal.rank(Tolta.ave(row[a]),ture,Null,1)" is return an error
Description: Add an expression like "Toltal.rank(Tolta.ave(row[a]),ture,Null,1)" is return an error.The nesting "Toltal" seem not to be work. Step to reproduce: 1.new a datasource and dataset 2.drag the dataset to layout veiw for a table 3.set a group on the table 4.Insert a data into the group header with the expression e.g. "Toltal.rank(Tolta.ave(row[a]),ture,Null,1)" Actual result: An error was thrown out Expected result: It should work correctly in order to support some requirments
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/expression/ExpressionProcessor.java
* result to scope. At last set the expression state which can be evaluated
	 * with true.
	 */
	public void calculate( ) throws DataException
	{
		List aggrList = helper.getAggregateList( 1 );
		AggregateTable table = helper.getAggregateTable( );
		if ( aggrList == null || table == null )
		{
			setExpressionState( );
			return;
		}		
		AggregateCalculator calculator = new AggregateCalculator( table,
				this.resultIterator );
		
		
		if ( helper.hasNestedAggregate( ) )
			calculator.populateValue( 
					(JSAggrValueObject) dataSet.getJSTempAggrValueObject() );
		Scriptable aggrObj = calculator.getJSAggrValueObject( );
		dataSet.setJSTempAggrValueObject( aggrObj );
		calculator.calculate(  dataSet.getScriptScope() );
		for ( int i = 0; i < aggrList.size( ); i++ )
		{
			AggregateObject obj = (AggregateObject) aggrList.get( i );
			obj.setAvailable( true );
			helper.addAvailableAggregateObj(obj);
		}
		setExpressionState( );
	}