On Sun, Jul 26, 2009 at 09:01:22PM -0700, Brian Troutwine wrote: > Hello all. > > I would like to define a data type that is the super-set of several > types and then each of the proper subset types. For example: >
data Foo = O !Odd | E !Even > data Odd = One | Three > data Even = Two | Four > > This, of course, does not work. It seems that such a thing should > possible to express entirely in the type system, but I cannot think of > how. Would someone be so kind as to explain how this sort of thing can > be accomplished? Do you have any reason not to do the above? -- Felipe. _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
