----------------------------------------------------------------------------- -- | -- Module : Control.Monad.Trans.Cont.Speculation -- Copyright : (C) 2011 Edward Kmett, Jake McArthur -- License : BSD-style (see the file LICENSE) -- -- Maintainer : Edward Kmett <ekmett@gmail.com> -- Stability : provisional -- Portability : portable -- -- Versions of the combinators from the 'speculation' package -- with the signature rearranged to enable them to be used -- directly as actions in the 'Cont' and 'ContT' monads. ---------------------------------------------------------------------------- module Control.Monad.Trans.Cont.Speculation where import Control.Monad.Trans.Cont import qualified Control.Concurrent.Speculation as Prim import Control.Concurrent.STM -- * Basic speculation -- | When a is unevaluated, @'spec' g a@ evaluates the current continuation -- with @g@ while testing if @g@ '==' @a@, if they differ, it re-evalutes the -- continuation with @a@. If @a@ was already evaluated, the continuation is -- just directly applied to @a@ instead. spec :: Eq a => a -> a -> ContT r m a spec g a = ContT $ \k -> Prim.spec g k a -- | As per 'spec', without the check for whether or not the second argument -- is already evaluated. spec' :: Eq a => a -> a -> ContT r m a spec' g a = ContT $ \k -> Prim.spec' g k a -- | @spec@ with a user supplied comparison function specBy :: (a -> a -> Bool) -> a -> a -> ContT r m a specBy f g a = ContT $ \k -> Prim.specBy f g k a -- | @spec'@ with a user supplied comparison function specBy' :: (a -> a -> Bool) -> a -> a -> ContT r m a specBy' f g a = ContT $ \k -> Prim.specBy' f g k a -- | @spec'@ with a user supplied comparison function specOn :: Eq c => (a -> c) -> a -> a -> ContT r m a specOn f g a = ContT $ \k -> Prim.specOn f g k a -- | @spec'@ with a user supplied comparison function specOn' :: Eq c => (a -> c) -> a -> a -> ContT r m a specOn' f g a = ContT $ \k -> Prim.specOn' f g k a -- * STM-based speculation specSTM :: Eq a => STM a -> a -> ContT r STM a specSTM g a = ContT $ \k -> Prim.specSTM g k a specSTM' :: Eq a => STM a -> a -> ContT r STM a specSTM' g a = ContT $ \k -> Prim.specSTM' g k a specOnSTM :: Eq c => (a -> STM c) -> STM a -> a -> ContT r STM a specOnSTM f g a = ContT $ \k -> Prim.specOnSTM f g k a specOnSTM' :: Eq c => (a -> STM c) -> STM a -> a -> ContT r STM a specOnSTM' f g a = ContT $ \k -> Prim.specOnSTM' f g k a specBySTM :: (a -> a -> STM Bool) -> STM a -> a -> ContT r STM a specBySTM f g a = ContT $ \k -> Prim.specBySTM f g k a specBySTM' :: (a -> a -> STM Bool) -> STM a -> a -> ContT r STM a specBySTM' f g a = ContT $ \k -> Prim.specBySTM' f g k a