[Haskell] Re: Parameterized Show

[George Russell]

Keean Schupke wrote:
> Do you need a language extension at all? You can certainly
> do it with the existing extensions!
> 
> data ShowDict a
> instance Show (ShowDict a) where
>    showsPrec _ (ShowDict a) = ...

I don't understand.  How does that help you to, for example, use a function which
requires Show Int but (say) substitute the standard function for which which shows
in hexadecimal?