[Haskell-cafe] Re: Generic types

[Adde]

While we're at it, I tried adding a class Length in between Unit and Meter, like
this:

class Unit u where
    shortName :: u -> String

class (Unit u) => Length u

instance Length Meter where
    shortName u = "m"


>From the information I can find on the web subclassing should include all
of the methods in the superclasses but I get this error:

`shortName' is not a (visible) method of class `Length'