anchor.diff:            S(2,NS) = TOKLST(2,I)
             S(3,NS) = TOKLST(3,I)
           ELSE
  +*         Note that if the stack holds an open parenthesis, this check
  +*         will always result in pushing the operator on the stack
  +*         because the parenthesis states are 500 while operator states
  +*         are 400.
             IF (S(1,NS).LE.TOKLST(1,I)) THEN
               NQ = NQ + 1
               Q(1,NQ) = S(1,NS)  ! POP OPERATOR FROM STACK INTO QUEUE
  
positive.code:             S(3,NS) = TOKLST(3,I)
            ENDIF
          END IF
        CASE DEFAULT
          WRITE(0,9001) STR(TOKLST(2,I):TOKLST(3,I))
          GOTO 9999
  
negative.code:       NS   = 0
        NQ   = 0
  *
  ***** Begin building POSTFIX queue from INFIX.
        DO 1001 I=1,NTOK
        SELECT CASE(100*(TOKLST(1,I)/100))
  *
        CASE (NUMB)
          NQ = NQ + 1
          Q(1,NQ) = TOKLST(1,I)
          Q(2,NQ) = TOKLST(2,I)
          Q(3,NQ) = TOKLST(3,I)
  *
        CASE (OPER)
          IF (NS.EQ.0) THEN
            NS = NS + 1
  