Re: [Haskell-cafe] Streaming bytes and performance

Don Stewart writes:

Here's the final program: [...]

Here is a version of the program that is just as fast: import Prelude hiding ( getContents, foldl ) import Data.ByteString.Char8 countSpace :: Int -> Char -> Int countSpace i c | c == ' ' || c == '\n' = i + 1 | otherwise = i main :: IO () main = getContents >>= print . foldl countSpace 0 Generally speaking, I/O performance is not about fancy low-level system features, it's about having a proper evaluation order: | $ ghc --make -O2 -funbox-strict-fields test1 && time ./test1 | 37627064 | | real 0m0.381s | user 0m0.356s | sys 0m0.023s Versus: | $ ghc --make -O2 -funbox-strict-fields test2 && time ./test2