anchor.diff:                An error of type TYPE-ERROR is signaled if RESULT-TYPE specifies a~@
                 size and that size is different from the sum of the lengths of~@
                 SEQUENCE-1 and SEQUENCE-2.~@
  +              An error of type TYPE-ERROR is signaled if SEQUENCE-1 is not a SEQUENCE.~@
  +              An error of type TYPE-ERROR is signaled if SEQUENCE-1 is a dotted list.~@
  +              No error is signaled if SEQUENCE-1 is a circular list.~@
  +              An error of type TYPE-ERROR is signaled if SEQUENCE-2 is not a SEQUENCE.~@
  +              An error of type TYPE-ERROR is signaled if SEQUENCE-2 is a dotted list.~@
  +              No error is signaled if SEQUENCE-2 is a circular list.~@
                 ~@
                 Portability notes:~@
                 The Common Lisp HyperSpec does not explicity mention that the SEQUENCE-1~@
  
positive.code:         (fmt "Lambda list: (RESULT-TYPE SEQUENCE-1 SEQUENCE-2 PREDICATE &key KEY)~@
                ~@
                Description:~@
                If PREDICATE represents the strictly-less-than function of a total order between~@
                the elements ******, then ********* For PREDICATE to represent such a~@
                function, it must always return the same value for a given pair of arguments.~@
                Furthermore, (funcall PREDICATE x y) and (funcall PREDICATE y x) must never~@
                both return true, and if both return false, then x and y are considired equal~@
                with respect to the total order.
                ~@
                If RESULT-TYPE is a subtype of LIST, then the resulting sequence will~@
                be a LIST.~@
  
negative.code:               then if some element in SEQUENCE-1 is equal to some element in SEQUENCE-2~@
                according to PREDICATE, then the element in SEQUENCE-1 will precede the~@
                element in SEQUENCE-2 in the resulting sequence.~@
                ~@
                If RESULT-TYPE is a subtype of LIST, then the CONS cells of any of SEQUENCE-1~@
                and SEQUENCE-2 that is a list will be used to construct the resulting sequence,~@
                thus destructively modifying it.  Thus, after a MERGE operation, the contents of~@
                such a sequence will be unpredictable, and should not be used.~@
                ~@
                Arguments:~@
                RESULT-TYPE is type specifier that specifies a sequence type.~@
  