On 26 March 2011 10:29, wren ng thornton
tryReadTChan :: TChan a -> STM (Maybe a)
+1 if we also add: tryReadChan :: Chan a -> IO (Maybe a)
peekTChan :: TChan a -> STM a tryPeekTChan :: TChan a -> STM (Maybe a)
+1 if we also add: peekChan :: Chan a -> IO a tryPeekChan :: Chan a -> IO (Maybe a)
tryReadTMVar :: TMVar a -> STM (Maybe a)
+1 if we also add: tryReadMVar :: MVar a -> IO (Maybe a)
modifyTVar :: TVar a -> (a -> a) -> STM () modifyTVar' :: TVar a -> (a -> a) -> STM ()
These are highly useful; I use them myself quite often. There's one issue though that has always bugged me about the current API: The types of modifyIORef and modifyMVar don't "line up": modifyIORef :: IORef a -> (a -> a) -> IO () modifyMVar :: MVar a -> (a -> IO (a,b)) -> IO b It would have been nicer if modifyMVar lined up with modifyIORef: modifyMVar :: MVar a -> (a -> a) -> IO () and have a separate: modifyMVarM :: MVar a -> (a -> IO (a,b)) -> IO b I guess it's difficult to change that at this stage. but maybe we can add: purelyModifyMVar :: MVar a -> (a -> a) -> IO () -- Note I don't like this name at all... Note that I'm in favor of adding: modifyTVar :: TVar a -> (a -> a) -> STM () but do we also need to add: modifyTVarM :: TVar a -> (a -> STM (a,b)) -> STM b so that MVars and TVars have more consistent APIs?
swapTVar :: TVar a -> a -> STM a +1
Thanks for the proposal! Bas