On Mon, May 13, 2013 at 11:43:41PM +0100, Tom Ellis wrote:
> On Mon, May 13, 2013 at 02:08:26PM -0800, Christopher Howard wrote:
> > instance Integral a => Coord2 (CircAppr a) where
> >
> > coords2 (CircAppr divns ang rad) =
> > let dAng = 2 * pi / (fromIntegral divns) in
> > let angles = map (* dAng) [0..divns] in
> > undefined -- To be coded...
>
> Your definition of "angles" forces "dAng" to be of type "a". Then in order
> to define "dAng" as the result of a "/" there must be a "Fractional" instance
> for
> "a".
You probably want
let angles = map ((* dAng) . fromInteger) [0..divns] in
...
instead.
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