Future.hs

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{-# LANGUAGE GADTs #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}

module Feldspar.Compiler.Imperative.FromCore.Future where

import Language.Syntactic

import Control.Monad.RWS (ask)

import Feldspar.Core.Types (Type,defaultSize)
import Feldspar.Core.Constructs.Future
import Feldspar.Core.Interpretation

import qualified Feldspar.Compiler.Imperative.Representation as Rep (Type(..))
import Feldspar.Compiler.Imperative.Representation (Entity(..), Block(..),Expression(..), fv)
import Feldspar.Compiler.Imperative.Frontend
import Feldspar.Compiler.Imperative.FromCore.Interpretation

import Data.Map (assocs)

instance Compile dom dom => Compile (FUTURE :|| Type) dom
  where
    compileExprSym = compileProgFresh

    compileProgSym (C' MkFuture) info (Just loc) (p :* Nil) = do
        env <- ask
        let args = [case lookup v (alias env) of
                         Nothing -> mkVariable (compileTypeRep t (defaultSize t)) v
                         Just (VarExpr e) -> e
                   | (v,SomeType t) <- assocs $ infoVars info
                   ] ++ fv loc
        -- Task core:
        ((_, ws), Block ds bl)  <- confiscateBigBlock $ do
            p' <- compileExprVar p
            tellProg [iVarPut loc p']
        funId  <- freshId
        let coreName = "task_core" ++ show funId
        tellDef [Proc coreName args [] $ Just (Block (decl ws ++ ds) bl)]
        -- Task:
        let taskName = "task" ++ show funId
        let runTask = Just $ toBlock $ run coreName args
        tellDef [Proc taskName [] [mkNamedRef "params" Rep.VoidType (-1)] runTask]
        -- Spawn:
        tellProg [iVarInit (AddrOf loc)]
        tellProg [spawn taskName args]

    compileProgSym (C' Await) _ loc (a :* Nil) = do
        fut <- compileExprVar a -- compileExpr a
        tellProg [iVarGet l fut | Just l <- [loc]]