Thomas Girod wrote: > Hi there. > > I'm trying to define a generic graph type here and don't understand on > one error I get. Here I come. > > module Graph > where > > class (Eq n, Eq e) => Topo a n e where > empty :: a > nodes :: a -> [n] > edges :: a -> [e]
This does not work without functional dependencies. Try: class (Eq n, Eq e) => Topo a n e | a -> n e where HTH Christian P.S. Integer comes in via defaulting (of 0 or 1) _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe