Prim.hs

-- | For defining @PrimMonad@ instances, for example:
--
-- @
-- -- Define a capability which includes Prim
-- data ExAndPrim e = MkExAndPrim (Exception String e) (P.Prim e)
--   -- Give it a Handle instance, as per Bluefin.Compound
--   deriving (Handle) via OneWayCoercibleHandle ExAndPrim
--   deriving stock (Generic)
--
-- instance (e \<: es) => OneWayCoercible (ExAndPrim e) (ExAndPrim es) where
--   oneWayCoercibleImpl = gOneWayCoercible
--
-- -- Define a monad M containing the Prim capability
-- newtype M e es a = MkM (ReaderT (ExAndPrim e) (Eff es) a)
--   deriving newtype (Functor, Applicative, Monad)
--
-- -- Define a way of running M
-- runM ::
--   (e1 \<: es, e2 \<: es) =>
--   Exception String e1 ->
--   P.Prim e2 ->
--   M es es r ->
--   Eff es r
-- runM ex prim (MkM m) =
--   runReaderT m (MkExAndPrim (mapHandle ex) (mapHandle prim))
--
-- -- Give M a PrimMonad instance
-- instance (e \<: es) => PrimMonad (M e es) where
--   type PrimState (M e es) = P.PrimStateEff e
--   primitive f =
--     MkM (ReaderT (\\(MkExAndPrim _ prim) -> P.'primitive' prim f))
--
-- -- ghci> example
-- -- Right [\"Hello\",\"World\"]
-- example :: Either String [String]
-- example = runPureEff $ try $ \\ex -> P.'runPrim' $ \\prim -> do
--   runM ex prim $ do
--     arr <- A.newArray 2 \"Hello\"
--     A.writeArray arr 1 \"World\"
--     for [0, 1] (A.readArray arr)
-- @
module Bluefin.Prim (Prim, runPrim, PrimStateEff, primitive) where

import Bluefin.Internal.Prim