anchor.diff:        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
  
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:           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
  