passing by reference... my darkest enemy
actual reason below:
In your case (without reference) the compiler generates a temporary object (int) for the first argument of your MyApplication constructor. You pass this temporary int to QApplication’s constructor (with int reference), which saves the address of this reference. Once your MyApplication constructor is done the temporary int is destroyed but QApplication still has its address.
module HandlerUtils where
import Control.Monad.Reader
import qualified Data.ByteString.Char8 as B
import Data.List
import RoomsAndClients
import CoreTypes
import Actions
thisClient :: Reader (ClientIndex, IRnC) ClientInfo
thisClient = do
(ci, rnc) <- ask
return $ rnc `client` ci
thisRoom :: Reader (ClientIndex, IRnC) RoomInfo
thisRoom = do
(ci, rnc) <- ask
let ri = clientRoom rnc ci
return $ rnc `room` ri
clientNick :: Reader (ClientIndex, IRnC) B.ByteString
clientNick = liftM nick thisClient
roomOthersChans :: Reader (ClientIndex, IRnC) [ClientChan]
roomOthersChans = do
(ci, rnc) <- ask
let ri = clientRoom rnc ci
return $ map (sendChan . client rnc) $ filter (/= ci) (roomClients rnc ri)
roomSameClanChans :: Reader (ClientIndex, IRnC) [ClientChan]
roomSameClanChans = do
(ci, rnc) <- ask
let ri = clientRoom rnc ci
let otherRoomClients = map (client rnc) . filter (/= ci) $ roomClients rnc ri
let cl = rnc `client` ci
let sameClanClients = Prelude.filter (\c -> clientClan c == clientClan cl) otherRoomClients
return $ map sendChan sameClanClients
roomClientsChans :: Reader (ClientIndex, IRnC) [ClientChan]
roomClientsChans = do
(ci, rnc) <- ask
let ri = clientRoom rnc ci
return $ map (sendChan . client rnc) (roomClients rnc ri)
thisClientChans :: Reader (ClientIndex, IRnC) [ClientChan]
thisClientChans = do
(ci, rnc) <- ask
return [sendChan (rnc `client` ci)]
answerClient :: [B.ByteString] -> Reader (ClientIndex, IRnC) [Action]
answerClient msg = liftM ((: []) . flip AnswerClients msg) thisClientChans
allRoomInfos :: Reader (a, IRnC) [RoomInfo]
allRoomInfos = liftM ((\irnc -> map (room irnc) $ allRooms irnc) . snd) ask
clientByNick :: B.ByteString -> Reader (ClientIndex, IRnC) (Maybe ClientIndex)
clientByNick n = do
(_, rnc) <- ask
let allClientIDs = allClients rnc
return $ find (\clId -> n == nick (client rnc clId)) allClientIDs