Proposal: Add bool to Data.Bool

[Edward Kmett]

I'm also rather against `mux`, not only on partiality grounds, but also on
the grounds that it is not very easily optimized away.


On Wed, Sep 11, 2013 at 2:23 PM, Henning Thielemann <
lemming at henning-thielemann.de> wrote:

>
> 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.
>
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