Bug 176107 row.__rownum cannot be directly used as group key
Create a table that bind it to a data set. Insert a group. For the Group On field, click on the "..." button to edit the expression, and select from "Availble Column Bindings" | "Table" | "RowNum". This creates a Group On Expression "row.__rownum". The resulting report design cannot be run. It produces error: Column binding "row.__rownum" does not exist. To workaround this, one must create another binding on the table and set its expression to "row.__rownum", then use the new binding as group key. This should not have been necessary. The "__rownum" binding should be implicitly available in all contexts that have a data set. E.g., it should be usable directly as group key, sort key, and in conditional format expressions, etc. Attached is a sample report that produces the error.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/expression/ExpressionCompilerUtil.java
}
	
	/**
	 * The utility method is to compile expression to get a list of column
	 * expressions which is depended by given expression.
	 * 
	 * @param expression
	 * @return
	 * @throws DataException
	 */
	public static List extractColumnExpression( IScriptExpression expression )
			throws DataException
	{
		List list = new ArrayList( );
		if ( expression == null )
			return list;
		populateColumnList( list, expression, true );
		return list;
	}
	
	/**
	 * 
	 * This utility method is to compile expression to get a list of column
	 * expressions which is depended by given expression.
	 * 
	 * @param expression
	 * @return
	 * @throws DataException
	 */
	public static List extractColumnExpression(