Re: [Haskell-cafe] Bloom Filter

ajb:

Quoting tom : This looks cool:

bytes2int = foldr ((. (256 *)) . (+)) 0 . (map toInteger)

but I'm not smart enough to parse it. This is both more readable and shorter:

bytes2int = foldr (\x r -> r*256 + fromInteger x) 0

Integer log2's are probably better done using integers only, or at least abstracted out into a separate function.

Reminds me of this code from Data.Binary: unroll :: Integer -> [Word8] unroll = unfoldr step where step 0 = Nothing step i = Just (fromIntegral i, i `shiftR` 8) roll :: [Word8] -> Integer roll = foldr unstep 0 where unstep b a = a `shiftL` 8 .|. fromIntegral b Which is a bit stream-fusion inspired, I must admit. -- Don