A function for computing non-integer representations ( http://en.wikipedia.org/wiki/Non-integer_representation )

baserep.hs

-- | baserep base num digits = (mantissa, exponent)
baserep :: (RealFrac a) => a -> a -> Int -> ([Int], Int)
baserep _ _ 0 = ([], 0)
baserep base num digits
  | num < 0     = undefined
  | num >= base = let (x, y) = baserep base (num / base) digits in (x, y+1)
  | otherwise   = let d = fromIntegral (floor num)
                      (x, y) = baserep base ((num - fromIntegral d) * base) (digits - 1)
                  in (d : x, y)