I see.. (Presumably you meant "instance Alg Sometype", "instance Vec Sometype" etc.) I have got it working now, and it looks like: 1) I can't specialise superclass methods with other class methods, within the class hierarchy, and 2) I have to instantiate each superclass individually, for any type. ...which is consistent with what you were saying. Thanks for clearing that up. Now I know what they meant what they meant by "leave your OO at the door". --- ajb@spamcop.net wrote: ...
What you'll have to do until then is something like this:
class Num a => Alg a where (<>) :: Mat m => m -> a -> a
multByVec :: (Vec v, Mat m) => m -> a -> a multByVec m v = fromColumn (m <> toColumn v)
class Alg v => Vec v where toRow, toColumn :: Mat m => v -> m fromRow, fromColumn :: Mat m => m -> v
fromRow = fromColumn . transpose toRow = transpose . toColumn
class Alg m => Mat m where transpose :: m -> m
class Alg SomeType where (<>) = multByVec
class Vec SomeType where toRow = {- etc etc -} {- and so on -}
Sorry, I wish there was a better answer.
Cheers, Andrew Bromage _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
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