On 1/3/07, Roberto Zunino <zunino at di.unipi.it> wrote: > I tried to define a Set datatype, > with the usual operations, so that it can be made a member of the > standard Monad class. Also, we can do this with oleg's technique of "Restricted Data Types Now": http://article.gmane.org/gmane.comp.lang.haskell.prime/483 Jim