I have a structure: data Attr = Attr { fg :: !Color, bg :: !Color, bold :: !Bool, blink :: !Bool, rv :: !Bool, halfBright :: !Bool, underline :: !Bool } deriving(Eq,Show,Ord) newtype Color = Color Int deriving(Eq,Show,Ord) but ghc is doing a phenominally bad job of unboxing it; so I'm trying to do it manually using a bitfield: -- |Data type representing character attributes. newtype Attr = Attr Int deriving (Eq) -- | Set the foreground color of an `Attr'. setFG :: Color -> Attr -> Attr setFG (Color c) (Attr a) = Attr ((a .&. 0xFFFFFF00) .|. c) -- | Get the foreground color of an `Attr'. getFG :: Attr -> Color getFG (Attr a) = Color (a .&. 0xFF) -- | Set the background color of an `Attr'. setBG :: Color -> Attr -> Attr setBG (Color c) (Attr a) = Attr ((a .&. 0xFFFF00FF) .|. (c `uncheckedShiftL` 8)) -- | Get the background color of an `Attr'. getBG :: Attr -> Color getBG (Attr a) = Color ((a .&. 0xFF00) `uncheckedShiftR` 8) -- | Set bold attribute of an `Attr'. setBold :: Attr -> Attr setBold (Attr a) = Attr (a .|. 0x10000) -- | Clear bold attribute of an `Attr'. clearBold :: Attr -> Attr clearBold (Attr a) = Attr (a .&. 0xFFFEFFFF) -- | Examine bold attribute of an `Attr'. isBold :: Attr -> Bool isBold (Attr a) = (a .&. 0x10000) /= 0 Urk. this is NO FUN. How do I stop the copy&paste and still generate fast code? Is there a better way? (Also, GHC seems unable to unbox strict fields that are newtypes. Can this be done, or should I abandon type safety and use type synonyms?) (Yes, this is performance critical code, and I have profiler output to back up this claim.) (Should this be directed to glasgow-haskell-users@ ?)