Designing the Procedure Logic › Advanced Action Diagram Features › Advanced Repeating Group Handling › Explicit Subscripting

Explicit Subscripting

When explicit subscripting is used, the procedure logic must ensure that the proper occurrence of the repeating group view is accessed at any given time.

The current occurrence is identified by its subscript. The value of a repeating group view's subscript is a number that corresponds to its position in the repeating view.

For example, consider a circus application in which the names and relative sizes of the circus's elephants are stored in a repeating group view. It might look like this:

If the repeating group view's subscript is set to 1, the occurrence for dumbo is current. If it is set to 4, the occurrence for LEON is correct.

Subscript values are set using the SUBSCRIPT option of the SET action. Each explicitly indexed repeating group view has a single subscript called SUBSCRIPT OF repeating-group-view. Assuming that the elephant list is stored in the repeating group view Elephants, the following action points to the occurrence for KING FORTINBRAS THE BRAVE:

SET SUBSCRIPT OF Elephants TO 3

When iterating through an explicitly subscripted repeating group view, the procedure logic must increment the subscript explicitly and must test for the end of the group explicitly. In the example shown in the following sample code causes the size of each elephant in the repeating group view to be set to elephantine.

Explicit Subscripting

SET SUBSCRIPT OF elephants TO 1
WHILE
     SUBSCRIPT OF elephants IS LESS THAN OR EQUAL TO LAST OF elephants
          SET elephant size TO elephantine
          SET SUBSCRIPT OF elephants TO SUBSCRIPT OF elephants +1

Had the repeating group view Elephants been defined as implicitly subscripted, the statement in the following sample code would accomplish the same result.

Implicit Subscripting

CHECK HOLIDAY
     IMPORTS:     Entity View incoming customer
     EXPORTS:     Entity View work status
     LOCALS:      Entity View work date
                  Entity View order_item
SET work date request TO HOLIDAY TEST
USE date_services WHICH IMPORTS incoming customer
                                work date
                  WHICH EXPORTS work status
     IF work status flag IS EQUAL TO H
          FOR EACH elephants
     EXIT STATE IS shipment_requested_on_a_holiday
     SET elephant_size TO “elephantine”

Note: Using implicit subscripting eliminates the need to initialize, maintain, and test the subscript value.

Certain action diagram constructs apply only to explicitly indexed repeating group views:

• FOR action
• SUBSCRIPT OF repeating-group-view special attribute
• LAST OF repeating-group-view special attribute
• It identifies the highest subscript value for which a repeating group view occurrence exists.
• MAX OF repeating-group-view special attribute
• It identifies the maximum cardinality of the repeating group view.

The special attributes SUBSCRIPT OF, LAST OF, and MAX OF are used in numeric expressions.

SUBSCRIPT OF and LAST OF can be the target of a SET statement.