TEXT AT POSITION
This field is set after an IF, AND, or OR statement using the IN relation is executed, which returns a true/false value of T (indicating that the first field includes the second field). The field indicates the starting position of the character string within the first field.
          IF       TAP 
 WORK DATA                  IN     JUNK 
 
    T     SET      --- 
 AI                         =  --- 
 TEXT AT POSITION 
    T     SET      --- 
 TEMP 79                    =      MESS 
 
    T     SET TEMP 79    AT 
 001 FOR 004 INTO AI  OF  TAP WORK DATA
In this example, the first occurrence of the text JUNK in the field TAP WORK DATA is replaced by the text MESS.