module ScientificFormat (sciformat) where import Ratio -- return prec+1 digits because I don't round sciformat prec r = sign ++ digits ++ "e" ++ show exp where (ds, exp) = tosci (abs numer) (denominator r) 0 numer = numerator r sign = if signum numer < 0 then "-" else "+" digits = show (head ds') ++ "." ++ concatMap show (tail ds') ds' = take (prec+1) (ds ++ repeat 0) tosci 0 _ _ = ([0], 0) tosci numer denom exp = case numer `div` denom of 0 -> tosci (10 * numer) denom (exp-1) x | x >= 10 -> tosci numer (10*denom) (exp+1) _ -> (digits numer denom, exp) digits n d = let (q,r) = n `quotRem` d in q : digits (10*r) d