Proposal: Better power for Rational

[Ian Lynagh]

On Sat, Sep 25, 2010 at 02:34:16AM +0200, Daniel Fischer wrote:
> 
> ratPow :: Integral a => Rational -> a -> Rational
> ratPow _ e
>     | e < 0     = error "Negative exponent"
> ratPow _ 0  = 1 :% 1
> ratPow r 1  = r
> ratPow (0:%y) _ = 0 :% 1
> ratPow (x:%1) e = (x^e) :% 1
> ratPow (x:%y) e = (x^e) :% (y^e)

Are you deliberately only doing this for Rational, rather than (Ratio t)
in general, to avoid differences in behaviour of Integral types?

If it was generalised, then we'd presumably want to use % for the final
result, so that
    (2^16 / 3) ^ 2 :: Ratio Int32
is (0 % 1) rather than (0 % 9).


Thanks
Ian