Beispiel: Klassen im Autotool

Grundsätzlich:

class Size b => Problem p i b | (p, i) -> b where
    describe :: p -> i -> Doc
    verify   :: p -> i -> b -> Reporter ()
    initial  :: p -> i -> b

instance Problem Analyse ( NFA Char Int ) Exp

Utilities:

class ToDoc  a where  toDoc :: a -> Doc
class Reader a where  reader :: String -> a
class Size   a where  size :: a -> Int