module Control.Reference.Combinators where
import Control.Reference.Representation
import Control.Instances.Morph
import Control.Monad
(&) :: (Monad w, Monad r) => Reference w r w' r' s t c d -> Reference w r w' r' c d a b
-> Reference w r w' r' s t a b
(&) l1 l2 = Reference (refGet l1 . refGet l2)
(refUpdate l1 . refSet l2)
(refUpdate l1 . refUpdate l2)
(refGet' l2 . refGet' l1)
(refUpdate' l2 . refSet' l1)
(refUpdate' l2 . refUpdate' l1)
infixl 6 &
(&+&) :: (RefMonads w r, RefMonads w' r', MonadPlus r, MonadPlus r', Morph [] r)
=> Reference w r w' r' s s a a -> Reference w r w' r' s s a a
-> Reference w r w' r' s s a a
l1 &+& l2 = Reference (\f a -> refGet l1 f a `mplus` refGet l2 f a)
(\v -> refSet l1 v >=> refSet l2 v )
(\trf -> refUpdate l1 trf
>=> refUpdate l2 trf )
(\f a -> refGet' l1 f a `mplus` refGet' l2 f a)
(\v -> refSet' l1 v >=> refSet' l2 v )
(\trf -> refUpdate' l1 trf
>=> refUpdate' l2 trf )
infixl 5 &+&
(&|&) :: (RefMonads m m')
=> Reference m m m' m' s t a b -> Reference m m m' m' s' t' a' b'
-> Reference m m m' m' (s, s') (t, t') (a, a') (b, b')
r1 &|& r2 = Reference (\f (s1,s2) -> ((,) <$> refGet r1 return s1 <*> refGet r2 return s2) >>= f)
(\(b1,b2) (s1,s2) -> (,) <$> refSet r1 b1 s1 <*> refSet r2 b2 s2)
(\f (s1,s2) -> do a1 <- refGet r1 return s1
a2 <- refGet r2 return s2
t1 <- refUpdate r1 (liftM fst . flip (curry f) a2) s1
t2 <- refUpdate r2 (liftM snd . curry f a1) s2
return (t1, t2) )
(\f (s1,s2) -> ((,) <$> refGet' r1 return s1 <*> refGet' r2 return s2) >>= f)
(\(b1,b2) (s1,s2) -> (,) <$> refSet' r1 b1 s1 <*> refSet' r2 b2 s2)
(\f (s1,s2) -> do a1 <- refGet' r1 return s1
a2 <- refGet' r2 return s2
t1 <- refUpdate' r1 (liftM fst . flip (curry f) a2) s1
t2 <- refUpdate' r2 (liftM snd . curry f a1) s2
return (t1, t2) )
infixl 5 &|&
turn :: Reference w r w' r' s t a b -> Reference w' r' w r a b s t
turn (Reference refGet refSet refUpdate refGet' refSet' refUpdate')
= (Reference refGet' refSet' refUpdate' refGet refSet refUpdate)