gistfile1.txt

class DangerouslyShow s where
    dangerouslyShow :: s -> T.Text

class (Show c, DangerouslyShow c) => Capability c where
    parse :: B.ByteString -> Either e c

class (MonadIO m, Capability v) => VerifyCapability m v where
    verify :: v -> m Bool

class (MonadIO m, Capability r, VerifyCapability m v) => ReadCapability m v r | r -> v where
    decodeMaybe :: r -> [B.ByteString] -> m (Maybe B.ByteString)                                                                    
    diminish :: r -> v  -- Could not deduce (ReadCapability m0 v r)