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Derive the various instances for Evaluator.

This commit is contained in:
Rob Rix 2018-03-02 10:41:31 -05:00
parent e44db3982e
commit 62189a026e

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@ -1,4 +1,4 @@
{-# LANGUAGE DataKinds, FunctionalDependencies, RankNTypes, UndecidableInstances #-}
{-# LANGUAGE DataKinds, FunctionalDependencies, GeneralizedNewtypeDeriving, RankNTypes, StandaloneDeriving, UndecidableInstances #-}
module Control.Abstract.Evaluator where
import Control.Applicative
@ -44,7 +44,14 @@ class MonadFail m => MonadEvaluator term value m | m -> term, m -> value where
-- | Run an action with a locally-modified table of unevaluated modules.
localModuleTable :: (Linker term -> Linker term) -> m a -> m a
instance MonadEvaluator term value (Evaluator effects term value) where
instance Members '[ Fail
, Reader (EnvironmentFor value)
, State (EnvironmentFor value)
, State (StoreFor value)
, Reader (Linker term)
, State (Linker value)
] effects
=> MonadEvaluator term value (Evaluator effects term value) where
getGlobalEnv = Evaluator get
modifyGlobalEnv f = Evaluator (modify f)
@ -61,41 +68,9 @@ instance MonadEvaluator term value (Evaluator effects term value) where
localModuleTable f a = Evaluator (local f (runEvaluator a))
newtype Evaluator effects term value a
= Evaluator
{ runEvaluator :: Members '[ Fail
, Reader (EnvironmentFor value)
, State (EnvironmentFor value)
, State (StoreFor value)
, Reader (Linker term)
, State (Linker value)
] effects
=> Eff effects a
}
newtype Evaluator effects term value a = Evaluator { runEvaluator :: Eff effects a }
deriving (Applicative, Functor, Monad)
instance Functor (Evaluator effects term value) where
fmap f (Evaluator run) = Evaluator (fmap f run)
instance Applicative (Evaluator effects term value) where
pure = Evaluator . pure
Evaluator runF <*> Evaluator runA = Evaluator (runF <*> runA)
instance Member NonDetEff effects => Alternative (Evaluator effects term value) where
empty = Evaluator empty
Evaluator runA <|> Evaluator runB = Evaluator (runA <|> runB)
instance Monad (Evaluator effects term value) where
return = pure
Evaluator runA >>= f = Evaluator (runA >>= runEvaluator . f)
instance MonadFail (Evaluator effects term value) where
fail s = Evaluator (fail s)
instance Member Fresh effects => MonadFresh (Evaluator effects term value) where
fresh = Evaluator fresh
reset t = Evaluator (reset t)
deriving instance Member Fail effects => MonadFail (Evaluator effects term value)
deriving instance Member NonDetEff effects => Alternative (Evaluator effects term value)
deriving instance Member Fresh effects => MonadFresh (Evaluator effects term value)