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/executor/transform/group/GroupInstanceFilter.java
* 
	 * @param cx
	 * @param filter
	 * @return
	 * @throws DataException
	 */
	private Object evaluteFilterExpression( Context cx, IFilterDefinition filter )
			throws DataException
	{
		IBaseExpression expr = filter.getExpression( );
		FilterUtil.prepareFilterExpression( expr, filterPass, this.populator.getEventHandler( ).getExecutorHelper( ) );
		Object result = ScriptEvalUtil.evalExpr( expr,
				cx,
				this.groupProcessor.getExpressionProcessor( ).getScope( ),
				"GroupFilter",
				0 );
		if ( result == null )
		{
			Object info = null;
			if ( expr instanceof IScriptExpression )
				info = ( (IScriptExpression) expr ).getText( );
			else
				info = expr;
			throw new DataException( ResourceConstants.INVALID_EXPRESSION_IN_FILTER,
					info );
		}
		return result;
	}
}