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inline hoist for transform

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Sandy Maguire 2019-02-22 08:05:01 -05:00
parent 7a4049bd6e
commit 87660ea594
1 changed files with 11 additions and 7 deletions
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18
src/Eff/Interpretation.hs
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@ -79,18 +79,22 @@ replace = naturally weaken
-- | Run an effect via the side-effects of a monad transformer.
transform
:: ( MonadTrans t
, MFunctor t
, forall m. Monad m => Monad (t m)
)
=> (forall m. Monad m => t m a -> m b)
-- ^ The strategy for getting out of the monad transformer.
=> (forall m. Eff r ~> m -> t (Eff r) ~> t m)
-- ^ The strategy for hoisting a natural transformation. This is usually
-- just 'hoist'.
-> (forall m. t m a -> m b)
-- ^ The strategy for getting out of the monad transformer. This is
-- usually just @runWhateverT@.
-> (eff ~> t (Eff r))
-> Eff (eff ': r) a
-> Eff r b
transform lower f (Freer m) = Freer $ \k -> lower $ m $ \u ->
case decomp u of
Left x -> lift $ k x
Right y -> hoist (usingFreer k) $ f y
transform hoist' lower f (Freer m) =
Freer $ \k -> lower $ m $ \u ->
case decomp u of
Left x -> lift $ k x
Right y -> hoist' (usingFreer k) $ f y
{-# INLINE[3] transform #-}
#endif