FIRST function

FIRST function

Returns a TRUE value if the current iteration of a DO, FOR EACH, or REPEAT . . . BREAK block is the first iteration of that block.

Syntax
FIRST ( break-group )
break-group

The name of a field or expression you name in the block header with the BREAK BY option.

Example

The r-first.p procedure displays the order number, OrderLines on the Order, the extended price of each OrderLine, and a total order value for each Order record:
r-first.p
DEFINE VARIABLE order-value AS DECIMAL NO-UNDO LABEL "Order-value".
 
FOR EACH Order NO-LOCK:
  DISPLAY Order.OrderNum.
  FOR EACH OrderLine OF Order BREAK BY OrderLine.Qty * OrderLine.Price:
    IF FIRST(OrderLine.Qty * OrderLine.Price) THEN 
      order-value = 0.
    order-value = order-value + OrderLine.Qty * OrderLine.Price.
    DISPLAY OrderLine.LineNum OrderLine.ItemNum 
      OrderLine.Qty * OrderLine.Price LABEL "Extended-price".
  END.
  DISPLAY order-value.
END. 
Because the inner FOR EACH block iterates until the AVM reads all the order-lines, the procedure must set the order-value variable to 0 each time a new order is used in that block. The FIRST function uses the (qty * price) expression as the break-group to keep track of whether or not the current iteration is the first iteration of the FOR EACH block.

See also

DO statement, FIRST-OF function, FOR statement, LAST function, LAST-OF function, REPEAT statement