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Diffstat (limited to 'third_party/bazel/rules_haskell/examples/transformers/Control/Monad/Trans/RWS/Strict.hs')
| -rw-r--r-- | third_party/bazel/rules_haskell/examples/transformers/Control/Monad/Trans/RWS/Strict.hs | 392 |
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diff --git a/third_party/bazel/rules_haskell/examples/transformers/Control/Monad/Trans/RWS/Strict.hs b/third_party/bazel/rules_haskell/examples/transformers/Control/Monad/Trans/RWS/Strict.hs deleted file mode 100644 index 557dd2028d..0000000000 --- a/third_party/bazel/rules_haskell/examples/transformers/Control/Monad/Trans/RWS/Strict.hs +++ /dev/null @@ -1,392 +0,0 @@ -{-# LANGUAGE CPP #-} -#if __GLASGOW_HASKELL__ >= 702 -{-# LANGUAGE Safe #-} -#endif -#if __GLASGOW_HASKELL__ >= 710 -{-# LANGUAGE AutoDeriveTypeable #-} -#endif ------------------------------------------------------------------------------ --- | --- Module : Control.Monad.Trans.RWS.Strict --- Copyright : (c) Andy Gill 2001, --- (c) Oregon Graduate Institute of Science and Technology, 2001 --- License : BSD-style (see the file LICENSE) --- --- Maintainer : R.Paterson@city.ac.uk --- Stability : experimental --- Portability : portable --- --- A monad transformer that combines 'ReaderT', 'WriterT' and 'StateT'. --- This version is strict; for a lazy version with the same interface, --- see "Control.Monad.Trans.RWS.Lazy". --- Although the output is built strictly, it is not possible to --- achieve constant space behaviour with this transformer: for that, --- use "Control.Monad.Trans.RWS.CPS" instead. ------------------------------------------------------------------------------ - -module Control.Monad.Trans.RWS.Strict ( - -- * The RWS monad - RWS, - rws, - runRWS, - evalRWS, - execRWS, - mapRWS, - withRWS, - -- * The RWST monad transformer - RWST(..), - evalRWST, - execRWST, - mapRWST, - withRWST, - -- * Reader operations - reader, - ask, - local, - asks, - -- * Writer operations - writer, - tell, - listen, - listens, - pass, - censor, - -- * State operations - state, - get, - put, - modify, - gets, - -- * Lifting other operations - liftCallCC, - liftCallCC', - liftCatch, - ) where - -import Control.Monad.IO.Class -import Control.Monad.Signatures -import Control.Monad.Trans.Class -#if MIN_VERSION_base(4,12,0) -import Data.Functor.Contravariant -#endif -import Data.Functor.Identity - -import Control.Applicative -import Control.Monad -#if MIN_VERSION_base(4,9,0) -import qualified Control.Monad.Fail as Fail -#endif -import Control.Monad.Fix -import Data.Monoid - --- | A monad containing an environment of type @r@, output of type @w@ --- and an updatable state of type @s@. -type RWS r w s = RWST r w s Identity - --- | Construct an RWS computation from a function. --- (The inverse of 'runRWS'.) -rws :: (r -> s -> (a, s, w)) -> RWS r w s a -rws f = RWST (\ r s -> Identity (f r s)) -{-# INLINE rws #-} - --- | Unwrap an RWS computation as a function. --- (The inverse of 'rws'.) -runRWS :: RWS r w s a -> r -> s -> (a, s, w) -runRWS m r s = runIdentity (runRWST m r s) -{-# INLINE runRWS #-} - --- | Evaluate a computation with the given initial state and environment, --- returning the final value and output, discarding the final state. -evalRWS :: RWS r w s a -- ^RWS computation to execute - -> r -- ^initial environment - -> s -- ^initial value - -> (a, w) -- ^final value and output -evalRWS m r s = let - (a, _, w) = runRWS m r s - in (a, w) -{-# INLINE evalRWS #-} - --- | Evaluate a computation with the given initial state and environment, --- returning the final state and output, discarding the final value. -execRWS :: RWS r w s a -- ^RWS computation to execute - -> r -- ^initial environment - -> s -- ^initial value - -> (s, w) -- ^final state and output -execRWS m r s = let - (_, s', w) = runRWS m r s - in (s', w) -{-# INLINE execRWS #-} - --- | Map the return value, final state and output of a computation using --- the given function. --- --- * @'runRWS' ('mapRWS' f m) r s = f ('runRWS' m r s)@ -mapRWS :: ((a, s, w) -> (b, s, w')) -> RWS r w s a -> RWS r w' s b -mapRWS f = mapRWST (Identity . f . runIdentity) -{-# INLINE mapRWS #-} - --- | @'withRWS' f m@ executes action @m@ with an initial environment --- and state modified by applying @f@. --- --- * @'runRWS' ('withRWS' f m) r s = 'uncurry' ('runRWS' m) (f r s)@ -withRWS :: (r' -> s -> (r, s)) -> RWS r w s a -> RWS r' w s a -withRWS = withRWST -{-# INLINE withRWS #-} - --- --------------------------------------------------------------------------- --- | A monad transformer adding reading an environment of type @r@, --- collecting an output of type @w@ and updating a state of type @s@ --- to an inner monad @m@. -newtype RWST r w s m a = RWST { runRWST :: r -> s -> m (a, s, w) } - --- | Evaluate a computation with the given initial state and environment, --- returning the final value and output, discarding the final state. -evalRWST :: (Monad m) - => RWST r w s m a -- ^computation to execute - -> r -- ^initial environment - -> s -- ^initial value - -> m (a, w) -- ^computation yielding final value and output -evalRWST m r s = do - (a, _, w) <- runRWST m r s - return (a, w) -{-# INLINE evalRWST #-} - --- | Evaluate a computation with the given initial state and environment, --- returning the final state and output, discarding the final value. -execRWST :: (Monad m) - => RWST r w s m a -- ^computation to execute - -> r -- ^initial environment - -> s -- ^initial value - -> m (s, w) -- ^computation yielding final state and output -execRWST m r s = do - (_, s', w) <- runRWST m r s - return (s', w) -{-# INLINE execRWST #-} - --- | Map the inner computation using the given function. --- --- * @'runRWST' ('mapRWST' f m) r s = f ('runRWST' m r s)@ -mapRWST :: (m (a, s, w) -> n (b, s, w')) -> RWST r w s m a -> RWST r w' s n b -mapRWST f m = RWST $ \ r s -> f (runRWST m r s) -{-# INLINE mapRWST #-} - --- | @'withRWST' f m@ executes action @m@ with an initial environment --- and state modified by applying @f@. --- --- * @'runRWST' ('withRWST' f m) r s = 'uncurry' ('runRWST' m) (f r s)@ -withRWST :: (r' -> s -> (r, s)) -> RWST r w s m a -> RWST r' w s m a -withRWST f m = RWST $ \ r s -> uncurry (runRWST m) (f r s) -{-# INLINE withRWST #-} - -instance (Functor m) => Functor (RWST r w s m) where - fmap f m = RWST $ \ r s -> - fmap (\ (a, s', w) -> (f a, s', w)) $ runRWST m r s - {-# INLINE fmap #-} - -instance (Monoid w, Functor m, Monad m) => Applicative (RWST r w s m) where - pure a = RWST $ \ _ s -> return (a, s, mempty) - {-# INLINE pure #-} - RWST mf <*> RWST mx = RWST $ \ r s -> do - (f, s', w) <- mf r s - (x, s'',w') <- mx r s' - return (f x, s'', w `mappend` w') - {-# INLINE (<*>) #-} - -instance (Monoid w, Functor m, MonadPlus m) => Alternative (RWST r w s m) where - empty = RWST $ \ _ _ -> mzero - {-# INLINE empty #-} - RWST m <|> RWST n = RWST $ \ r s -> m r s `mplus` n r s - {-# INLINE (<|>) #-} - -instance (Monoid w, Monad m) => Monad (RWST r w s m) where -#if !(MIN_VERSION_base(4,8,0)) - return a = RWST $ \ _ s -> return (a, s, mempty) - {-# INLINE return #-} -#endif - m >>= k = RWST $ \ r s -> do - (a, s', w) <- runRWST m r s - (b, s'',w') <- runRWST (k a) r s' - return (b, s'', w `mappend` w') - {-# INLINE (>>=) #-} -#if !(MIN_VERSION_base(4,13,0)) - fail msg = RWST $ \ _ _ -> fail msg - {-# INLINE fail #-} -#endif - -#if MIN_VERSION_base(4,9,0) -instance (Monoid w, Fail.MonadFail m) => Fail.MonadFail (RWST r w s m) where - fail msg = RWST $ \ _ _ -> Fail.fail msg - {-# INLINE fail #-} -#endif - -instance (Monoid w, MonadPlus m) => MonadPlus (RWST r w s m) where - mzero = RWST $ \ _ _ -> mzero - {-# INLINE mzero #-} - RWST m `mplus` RWST n = RWST $ \ r s -> m r s `mplus` n r s - {-# INLINE mplus #-} - -instance (Monoid w, MonadFix m) => MonadFix (RWST r w s m) where - mfix f = RWST $ \ r s -> mfix $ \ ~(a, _, _) -> runRWST (f a) r s - {-# INLINE mfix #-} - -instance (Monoid w) => MonadTrans (RWST r w s) where - lift m = RWST $ \ _ s -> do - a <- m - return (a, s, mempty) - {-# INLINE lift #-} - -instance (Monoid w, MonadIO m) => MonadIO (RWST r w s m) where - liftIO = lift . liftIO - {-# INLINE liftIO #-} - -#if MIN_VERSION_base(4,12,0) -instance Contravariant m => Contravariant (RWST r w s m) where - contramap f m = RWST $ \r s -> - contramap (\ (a, s', w) -> (f a, s', w)) $ runRWST m r s - {-# INLINE contramap #-} -#endif - --- --------------------------------------------------------------------------- --- Reader operations - --- | Constructor for computations in the reader monad (equivalent to 'asks'). -reader :: (Monoid w, Monad m) => (r -> a) -> RWST r w s m a -reader = asks -{-# INLINE reader #-} - --- | Fetch the value of the environment. -ask :: (Monoid w, Monad m) => RWST r w s m r -ask = RWST $ \ r s -> return (r, s, mempty) -{-# INLINE ask #-} - --- | Execute a computation in a modified environment --- --- * @'runRWST' ('local' f m) r s = 'runRWST' m (f r) s@ -local :: (r -> r) -> RWST r w s m a -> RWST r w s m a -local f m = RWST $ \ r s -> runRWST m (f r) s -{-# INLINE local #-} - --- | Retrieve a function of the current environment. --- --- * @'asks' f = 'liftM' f 'ask'@ -asks :: (Monoid w, Monad m) => (r -> a) -> RWST r w s m a -asks f = RWST $ \ r s -> return (f r, s, mempty) -{-# INLINE asks #-} - --- --------------------------------------------------------------------------- --- Writer operations - --- | Construct a writer computation from a (result, output) pair. -writer :: (Monad m) => (a, w) -> RWST r w s m a -writer (a, w) = RWST $ \ _ s -> return (a, s, w) -{-# INLINE writer #-} - --- | @'tell' w@ is an action that produces the output @w@. -tell :: (Monad m) => w -> RWST r w s m () -tell w = RWST $ \ _ s -> return ((),s,w) -{-# INLINE tell #-} - --- | @'listen' m@ is an action that executes the action @m@ and adds its --- output to the value of the computation. --- --- * @'runRWST' ('listen' m) r s = 'liftM' (\\ (a, w) -> ((a, w), w)) ('runRWST' m r s)@ -listen :: (Monad m) => RWST r w s m a -> RWST r w s m (a, w) -listen m = RWST $ \ r s -> do - (a, s', w) <- runRWST m r s - return ((a, w), s', w) -{-# INLINE listen #-} - --- | @'listens' f m@ is an action that executes the action @m@ and adds --- the result of applying @f@ to the output to the value of the computation. --- --- * @'listens' f m = 'liftM' (id *** f) ('listen' m)@ --- --- * @'runRWST' ('listens' f m) r s = 'liftM' (\\ (a, w) -> ((a, f w), w)) ('runRWST' m r s)@ -listens :: (Monad m) => (w -> b) -> RWST r w s m a -> RWST r w s m (a, b) -listens f m = RWST $ \ r s -> do - (a, s', w) <- runRWST m r s - return ((a, f w), s', w) -{-# INLINE listens #-} - --- | @'pass' m@ is an action that executes the action @m@, which returns --- a value and a function, and returns the value, applying the function --- to the output. --- --- * @'runRWST' ('pass' m) r s = 'liftM' (\\ ((a, f), w) -> (a, f w)) ('runRWST' m r s)@ -pass :: (Monad m) => RWST r w s m (a, w -> w) -> RWST r w s m a -pass m = RWST $ \ r s -> do - ((a, f), s', w) <- runRWST m r s - return (a, s', f w) -{-# INLINE pass #-} - --- | @'censor' f m@ is an action that executes the action @m@ and --- applies the function @f@ to its output, leaving the return value --- unchanged. --- --- * @'censor' f m = 'pass' ('liftM' (\\ x -> (x,f)) m)@ --- --- * @'runRWST' ('censor' f m) r s = 'liftM' (\\ (a, w) -> (a, f w)) ('runRWST' m r s)@ -censor :: (Monad m) => (w -> w) -> RWST r w s m a -> RWST r w s m a -censor f m = RWST $ \ r s -> do - (a, s', w) <- runRWST m r s - return (a, s', f w) -{-# INLINE censor #-} - --- --------------------------------------------------------------------------- --- State operations - --- | Construct a state monad computation from a state transformer function. -state :: (Monoid w, Monad m) => (s -> (a,s)) -> RWST r w s m a -state f = RWST $ \ _ s -> case f s of (a,s') -> return (a, s', mempty) -{-# INLINE state #-} - --- | Fetch the current value of the state within the monad. -get :: (Monoid w, Monad m) => RWST r w s m s -get = RWST $ \ _ s -> return (s, s, mempty) -{-# INLINE get #-} - --- | @'put' s@ sets the state within the monad to @s@. -put :: (Monoid w, Monad m) => s -> RWST r w s m () -put s = RWST $ \ _ _ -> return ((), s, mempty) -{-# INLINE put #-} - --- | @'modify' f@ is an action that updates the state to the result of --- applying @f@ to the current state. --- --- * @'modify' f = 'get' >>= ('put' . f)@ -modify :: (Monoid w, Monad m) => (s -> s) -> RWST r w s m () -modify f = RWST $ \ _ s -> return ((), f s, mempty) -{-# INLINE modify #-} - --- | Get a specific component of the state, using a projection function --- supplied. --- --- * @'gets' f = 'liftM' f 'get'@ -gets :: (Monoid w, Monad m) => (s -> a) -> RWST r w s m a -gets f = RWST $ \ _ s -> return (f s, s, mempty) -{-# INLINE gets #-} - --- | Uniform lifting of a @callCC@ operation to the new monad. --- This version rolls back to the original state on entering the --- continuation. -liftCallCC :: (Monoid w) => - CallCC m (a,s,w) (b,s,w) -> CallCC (RWST r w s m) a b -liftCallCC callCC f = RWST $ \ r s -> - callCC $ \ c -> - runRWST (f (\ a -> RWST $ \ _ _ -> c (a, s, mempty))) r s -{-# INLINE liftCallCC #-} - --- | In-situ lifting of a @callCC@ operation to the new monad. --- This version uses the current state on entering the continuation. -liftCallCC' :: (Monoid w) => - CallCC m (a,s,w) (b,s,w) -> CallCC (RWST r w s m) a b -liftCallCC' callCC f = RWST $ \ r s -> - callCC $ \ c -> - runRWST (f (\ a -> RWST $ \ _ s' -> c (a, s', mempty))) r s -{-# INLINE liftCallCC' #-} - --- | Lift a @catchE@ operation to the new monad. -liftCatch :: Catch e m (a,s,w) -> Catch e (RWST r w s m) a -liftCatch catchE m h = - RWST $ \ r s -> runRWST m r s `catchE` \ e -> runRWST (h e) r s -{-# INLINE liftCatch #-} |