DO_LOOP, EXIT_LOOP, END_LOOP action

The actions allows to implement a loop.

[FOR _ctrlVar [RANGE struct | = lBoundExpr TO uBoundExpr] ] DO_LOOP ...; actions 1 [EXIT_LOOP [expression]] ...; actions 2 [EXIT_LOOP [expression]] ...; akctions 3 END_LOOP

expression

in

Expression of Boolean type.

The loop has two variants:

1. Loop with using a control variable. At the beginning of the loop, the control variable is set to the value 1 in case of the variant with using the RANGE keyword, or it is set to the value given by the expression lBoundExpr. Value of the expression must be valid. High limit for the value of the control variable is evaluated once, too. In the first case (RANGE), the high limit is the size of given structure (struct\DIM). In the second case, the high limit is acquired by evaluation of the expression uBoundExpr. Value of the expression must be valid. During individual iterations, the control variable of the loop will be increased in successive steps up to the high limit. The control variable must be defined as INT type. It can be changed in the loop body. Possible invalidation of its value will causes an error when executing the END_LOOP action. The loop can be aborted by the EXIT_LOOP action.
   After terminating the cycle, the value of the control variable is the value of the high limit increased by 1.
   
   

   INT _i INT _uBound _uBound := 10 FOR _i=2 TO _uBound DO_LOOP _uBound := _uBound + 1 ; value change has no effect on the number of iterations END_LOOP ; value of the variable _i is 11

   
   

   INT _i RECORD (SD.ArchVal) _struct REDIM _struct[10] FOR _i RANGE _struct DO_LOOP REDIM _struct[2] ; value change has no effect on the number of iterations END_LOOP ; value of the variable _i is 11

2. Loop with using no control variable. Actions enclosed between the actions DO_LOOP a END_LOOP will be cyclically executed. The action EXIT_LOOP may terminate a cycle. If the action is with a parameter, then the loop will be terminated when the expression will get the value @TRUE.
   
   

   INT _i _i := 1 DO_LOOP EXIT_LOOP _i = 10 _i := _i + 1 END_LOOP

   
   Equivalent declaration with no conditional termination of the loop:
   
   

   INT _i _i := 1DO_LOOP IF _i = 10 THEN EXIT_LOOP ENDIF _i := _i + 1 END_LOOP

Invalid notation of a loop occurs, if its beginning and end is ''crossed'' with the action IF THEN.

For example:

INT _i _i := 1 IF Sec = 1 THEN DO_LOOP ENDIF EXIT_LOOP _i = 10 _i := _i + 1 END_LOOP

or

INT _i _i := 1 DO_LOOP IF _i = 10 THEN EXIT_LOOP ENDIF _i := _i + 1 IF Sec = 1 THEN _i := _i + 1 END_LOOP ELSE END_LOOP ENDIF