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gyehoek-hs/src/Gyehoek/CPS/Contify.hs
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2026-09-05 20:22:07 -06:00

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Haskell

{-# LANGUAGE ApplicativeDo #-}
module Gyehoek.CPS.Contify
( contifyProgram
) where
import Control.Monad.Tardis
import Gyehoek.CPS.Syntax
import Gyehoek.Prelude
import qualified Data.HashSet as HS
import Control.Lens.Unsound (adjoin)
import Debug.Pretty.Simple
import qualified Data.HashMap.Strict as H
import Control.Monad.Writer.Lazy
import Control.Monad.Trans.Tardis (liftTardisT)
-- | ain't no way...
-- type T = WriterT (HashSet Name) (Tardis (HashSet Name) (HashSet Name))
type T = TardisT (HashSet Name) (HashSet Name) (Writer (HashSet Name))
evalT :: T a -> a
-- evalT = (`evalTardis` (mempty,mempty)) . fmap fst . runWriterT
evalT = fst . runWriter . (`evalTardisT` (mempty,mempty))
runT :: T a -> (a, HashSet Name)
-- runT = (`evalTardis` (mempty,mempty)) . runWriterT
runT = runWriter . (`evalTardisT` (mempty,mempty))
-- | inline function if it hasn't been used in the past, and won't
-- be used in the future.
tryInline :: Name -> Kappa -> T Kexp
tryInline kname kap = do
modifyBackwards (HS.insert kname)
p <- getsPast (HS.member kname)
modifyForwards (HS.insert kname)
q <- getsFuture (HS.member kname)
let c = p || q
liftTardisT . tell $ if c then HS.singleton kname else mempty
pure $ if c
then KexpVar kname
else KexpKappa kap
getKap :: HashMap Name Abs -> Name -> Maybe Kappa
getKap g kname = g ^? ix kname . #AbsKappa
contify :: HashMap Name Abs -> Exp -> T Exp
contify g = transformM \case
ExpApply f xs (KexpVar kname) | Just kap <- getKap g kname
-> ExpApply f xs <$> tryInline kname kap
ExpPrim p (KexpVar kname) | Just kap <- getKap g kname
-> ExpPrim p <$> tryInline kname kap
e -> pure e
contifyProgram :: HoistedProgram -> Eff es HoistedProgram
contifyProgram p = do
let g = p.bindings
let (p',contifiedVars) =
runT $
traverseOf
(adjoin
(#bindings . each . body)
(#body . body))
(contify g)
p
pTraceShowM contifiedVars
-- pure $ p' & #bindings %~ H.filterWithKey \k _ -> HS.member k contifiedVars
pure p'