Proposal: Add bool to Data.Bool

[Henning Thielemann]

On Wed, 11 Sep 2013, Greg Fitzgerald wrote:

> I'd prefer something more like:
>
>    mux :: Enum b => [a] -> b -> a
>    mux xs x = xs !! fromEnum x
>
> so then 'bool' could be implemented as:
>
>    bool :: a -> a -> Bool -> a
>    bool f t = mux [f, t]
>
> but 'mux' needs a stronger type signature.  The size of the enum is
> known at compile-time.  Is there any way to constrain the input list

I don't like a total function to be implemented using a non-total function 
(!!). Additionally your implementation relies on fromEnum True == 1, which 
is a bad thing.