Re: [Haskell-cafe] int to bin, bin to int

prstanley:

Hi intToBin :: Int -> [Int] intToBin 1 = [1] intToBin n = (intToBin (n`div`2)) ++ [n `mod` 2]

binToInt :: [Integer] -> Integer binToInt [] = 0 binToInt (x:xs) = (x*2^(length xs)) + (binToInt xs)

Any comments and/or criticisms on the above definitions would be appreciated.

One of my favourites is: unroll :: Integer -> [Word8] unroll = unfoldr step where step 0 = Nothing step i = Just (fromIntegral i .&. 1, i `shiftR` 1) roll :: [Word8] -> Integer roll = foldr unstep 0 where unstep b a = a `shiftL` 1 .|. fromIntegral b -- Don