{-# LANGUAGE OverloadedLists #-}
module Gyehoek.CPS.Convert
  ( convert
  ) where

import Gyehoek.CPS.Syntax
import Gyehoek.Scheme.Syntax qualified as Scm
import Gyehoek.GenSym
import Data.List.NonEmpty (NonEmpty((:|)))
import Effectful
import Control.Monad.Cont qualified as Cont


-- 뻘짓이어라
telescope
  :: Traversable t
  => (a -> (b -> r) -> r)
  -> t a -> (t b -> r) -> r
telescope f = Cont.runCont . traverse (Cont.cont . f)

convert
  :: forall es. (GenSym :> es)
  => Scm.Exp -> (Val -> Eff es Exp) -> Eff es Exp

convert (Scm.ExpVar x) k = k $ ValVar x
convert (Scm.ExpLit l) k = k $ ValLit l

convert (Scm.ExpPrim p) k =
  telescope (convert @es) p \p' -> do
    r <- gensym' "r"
    ExpPrim p' [r] <$> k (ValVar r)

convert (Scm.ExpLambda xs e) k = do
  f <- gensym' "f"
  ktail <- gensym' "ktail"
  m <- convert e $ \e' ->
    pure $ ExpApply (ValVar ktail) [e']
  ExpFix [(f, MkKappa (xs ++ [ktail]) m)] <$> k (ValVar f)

convert (Scm.ExpApply f xs) k =
  telescope (convert @es) (f:|xs) \(f':|xs') -> do
    r <- gensym' "r"
    x <- gensym' "x"
    m <- k (ValVar x)
    pure $ ExpFix [(r, MkKappa [x] m)] $ ExpApply f' (xs' ++ [ValVar r])

convert (Scm.ExpBegin xs) k = _

convert _ k = _