MutableToPure.hs

{-# LANGUAGE GADTs #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE MultiParamTypeClasses #-}

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-- Copyright (c) 2009-2011, ERICSSON AB
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--       this list of conditions and the following disclaimer.
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{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE CPP #-}

module Feldspar.Core.Constructs.MutableToPure
    ( MutableToPure (..)
    ) where

import qualified Control.Exception as C
import Data.Array.IArray
#if __GLASGOW_HASKELL__>=704
import Data.Array.MArray (freeze)
import Data.Array.Unsafe (unsafeFreeze)
#else
import Data.Array.MArray (freeze, unsafeFreeze)
#endif
import System.IO.Unsafe

import Language.Syntactic
import Language.Syntactic.Constructs.Binding

import Feldspar.Lattice
import Feldspar.Core.Types
import Feldspar.Core.Interpretation

data MutableToPure a where
  RunMutableArray :: Type a => MutableToPure (Mut (MArr a) :-> Full [a])
  WithArray       :: Type b => MutableToPure (MArr a :-> ([a] -> Mut b) :-> Full (Mut b))

instance Semantic MutableToPure
  where
    semantics RunMutableArray = Sem "runMutableArray" runMutableArrayEval
    semantics WithArray       = Sem "withArray"       withArrayEval

runMutableArrayEval :: forall a . Mut (MArr a) -> [a]
runMutableArrayEval m = unsafePerformIO $
                        do marr <- m
                           iarr <- unsafeFreeze marr
                           return (elems (iarr :: Array WordN a))

withArrayEval :: forall a b. MArr a -> ([a] -> Mut b) -> Mut b
withArrayEval ma f
    = do a <- f (elems (unsafePerformIO $ freeze ma :: Array WordN a))
         C.evaluate a

instance Equality MutableToPure where equal = equalDefault; exprHash = exprHashDefault
instance Render   MutableToPure where renderArgs = renderArgsDefault
instance ToTree   MutableToPure
instance Eval     MutableToPure where evaluate = evaluateDefault
instance EvalBind MutableToPure where evalBindSym = evalBindSymDefault
instance Sharable MutableToPure

instance Typed MutableToPure
  where
    typeDictSym RunMutableArray = Just Dict
    typeDictSym _ = Nothing


instance AlphaEq dom dom dom env => AlphaEq MutableToPure MutableToPure dom env
  where
    alphaEqSym = alphaEqSymDefault

instance SizeProp MutableToPure
  where
    sizeProp RunMutableArray _ = universal
    sizeProp WithArray       _ = universal

instance (MutableToPure :<: dom, Optimize dom dom) => Optimize MutableToPure dom
  where
    constructFeatUnOpt RunMutableArray args = constructFeatUnOptDefaultTyp typeRep RunMutableArray args
    constructFeatUnOpt WithArray args       = constructFeatUnOptDefaultTyp (MutType typeRep) WithArray args