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The STM Monad

• Monad (support "do" notation and sequencing)

 data STM a
 instance Monad STM

• Exceptions

 throw :: Exception -> STM a
 catch :: STM a -> (Exception->STM a) -> STM a

• STM computations

 atomic :: STM a -> IO a
 retry :: STM a
 orElse :: STM a -> STM a -> STM a

• Transactional variables

 data TVar a
 newTVar :: a -> STM (TVar a)
 readTVar :: TVar a -> STM a
 writeTVar :: TVar a -> a -> STM ()

• It's an instance of MonadPlus (whatever that means)

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