Experiments with unboxed mutable records

SomeStruct.hs

module Main
    where

import Control.Monad
import Data.IORef

data SomeStruct = SomeStruct { someField :: {-# UNPACK #-} !Int,
                               someOtherField :: {-# UNPACK #-} !Int,
                               yetAnotherField :: {-# UNPACK #-} !Float }

main :: IO ()
main = do i <- newIORef $ SomeStruct 1 2 6.8
          modifyIORef i (\s -> s { someOtherField = 23 })
          f <- liftM someOtherField $ readIORef i
          print f
          return ()