SYMMETRIC-DIFFERENCE-OF-SETS ============================ syntax: (symmetric-difference-of-sets <evaluates-to <set-of A (...)>> <evaluates-to <set-of B (...)>> [:TYPE <evaluates-to type-name>] [:TEST <lisp-type: function>]) ==> #<set-of X (...)> This function produces the symmetric difference of two sets. Warning: type checking may cause an error! Speed UP: (difference-of-sets (union-of-sets set1 set2 :test test) (intersection-of-sets set1 set2 :test test) :test test) example: >(symmetric-difference-of-sets *capital-cities* *cities*) #<set-of CITY (...)> >(set-to-list *) (#<CITY BONN> #<CITY DORTMUND>)