Re: [Haskell-Cafe] Parsing bytestream

On Tue, Nov 9, 2010 at 8:10 AM, C K Kashyap wrote: ] I think I can restate my problem like this --- ] ] If I have a list of actions as follows - ] ] import Data.Word ] import Data.Binary.Get ] ] data MyAction = A1 (Get Word8) | A2 (Get Word16) ] ] a = A1 getWord8 ] b = A2 getWord16be ] ] listOfActions = [a,b,a] ] ] How can I execute the "listOfActions" inside of a Get Monad and get ] the output as a list? Do you mean, something like this?

import Control.Applicative ((<$>))

data MyAction m = A1 (m Word8) | A2 (m Word16)

a = A1 getWord8 b = A2 getWord16be

listOfActions = [a,b,a]

newtype Id a = Id a

getAction :: MyAction Get -> Get (MyAction Id) getAction (A1 act) = A1 . Id <$> act getAction (A2 act) = A2 . Id <$> act

getActions :: [MyAction Get] -> Get [MyAction Id] getActions = mapM getAction

-- Felipe.