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/IExpressionProcessor.java
* Get the scope on which the expression is compiled
	 * 
	 * @return
	 */
	public Scriptable getScope( );
	/**
	 * Compile the compilable expression in the given IComputedColumnState
	 * instance
	 * 
	 * @param computedColumns
	 */
	public void compileComputedColumn( IComputedColumnsState computedColumns );
	/**
	 * Compile the filter expression. If the filter contains the indirect nested
	 * row reference, this is, it refers to the row object in computed columns,
	 * then replace the field of expression and recompile the filter expression
	 * 
	 * @param filterState
	 * @param computedColumns
	 * @throws DataException
	 */
	public void compileFilter( List filterState,
			IComputedColumnsState computedColumns );
	/**
	 * Calculate the aggregations.If the aggregate pass level is less than or
	 * equal to 1, the value of this aggregate is available. And the value will
	 * be register in aggregate table.If the pass level is more than 1, the
	 * value is not accessed. The calculation will push to next time.
	 * 
	 */