{-# LANGUAGE AllowAmbiguousTypes #-} -- For ShowLetName
{-# LANGUAGE BangPatterns #-} -- For makeSharingName
{-# LANGUAGE DataKinds #-} -- For ShowLetName
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE ExistentialQuantification #-} -- For SharingName
-- {-# LANGUAGE MagicHash #-} -- For unsafeCoerce#
module Symantic.Typed.ObserveSharing where

import Control.Applicative (Applicative(..))
import Control.Monad (Monad(..))
import Data.Bool (Bool(..))
import Data.Eq (Eq(..))
import Data.Foldable (foldMap)
import Data.Function (($), (.))
import Data.Functor ((<$>))
import Data.Functor.Compose (Compose(..))
import Data.HashMap.Strict (HashMap)
import Data.HashSet (HashSet)
import Data.Hashable (Hashable, hashWithSalt, hash)
import Data.Int (Int)
import Data.Maybe (Maybe(..), isNothing)
import Data.Monoid (Monoid(..))
import Data.Ord (Ord(..))
import Data.String (String)
-- import GHC.Exts (Int(..))
-- import GHC.Prim (unsafeCoerce#)
import GHC.StableName (StableName(..), makeStableName, hashStableName, eqStableName)
-- import Numeric (showHex)
import Prelude ((+), error)
import System.IO (IO)
import System.IO.Unsafe (unsafePerformIO)
import Text.Show (Show(..))
import qualified Control.Monad.Trans.Class as MT
import qualified Control.Monad.Trans.Reader as MT
import qualified Control.Monad.Trans.State as MT
import qualified Control.Monad.Trans.Writer as MT
import qualified Data.HashMap.Strict as HM
import qualified Data.HashSet as HS

import Symantic.Typed.Derive

-- * Class 'Letable'
-- | This class is not for end-users like usual symantic operators,
-- here 'shareable' and 'ref' are introduced by 'observeSharing'.
class Letable letName repr where
  -- | @('ref' isRec letName)@ is a reference to @(letName)@.
  -- @(isRec)@ is 'True' iif. this 'ref'erence is recursive,
  -- ie. is reachable within its 'shareable' definition.
  ref :: Bool -> letName -> repr a
  ref Bool
isRec letName
n = Derived repr a -> repr a
forall (repr :: * -> *) a.
LiftDerived repr =>
Derived repr a -> repr a
liftDerived (Bool -> letName -> Derived repr a
forall letName (repr :: * -> *) a.
Letable letName repr =>
Bool -> letName -> repr a
ref Bool
isRec letName
n)
  default ref ::
    FromDerived (Letable letName) repr =>
    Bool -> letName -> repr a

  -- | @('shareable' letName x)@ let-binds @(letName)@ to be equal to @(x)@.
  shareable :: letName -> repr a -> repr a
  shareable letName
n = (Derived repr a -> Derived repr a) -> repr a -> repr a
forall (repr :: * -> *) a b.
LiftDerived1 repr =>
(Derived repr a -> Derived repr b) -> repr a -> repr b
liftDerived1 (letName -> Derived repr a -> Derived repr a
forall letName (repr :: * -> *) a.
Letable letName repr =>
letName -> repr a -> repr a
shareable letName
n)
  default shareable ::
    FromDerived1 (Letable letName) repr =>
    letName -> repr a -> repr a

-- * Class 'MakeLetName'
class MakeLetName letName where
  makeLetName :: SharingName -> IO letName

-- ** Type 'ShowLetName'
-- | Useful on golden unit tests because 'StableName'
-- change often when changing unrelated source code
-- or even changing basic GHC or executable flags.
class ShowLetName (showName::Bool) letName where
  showLetName :: letName -> String
-- | Like 'Show'.
instance Show letName => ShowLetName 'True letName where
  showLetName :: letName -> String
showLetName = letName -> String
forall letName. Show letName => letName -> String
show
-- | Always return @"<hidden>"@,
instance ShowLetName 'False letName where
  showLetName :: letName -> String
showLetName letName
_p = String
"<hidden>"

-- * Type 'SharingName'
-- | Note that the observable sharing enabled by 'StableName'
-- is not perfect as it will not observe all the sharing explicitely done.
--
-- Note also that the observed sharing could be different between ghc and ghci.
data SharingName = forall a. SharingName (StableName a)
-- | @('makeSharingName' x)@ is like @('makeStableName' x)@ but it also forces
-- evaluation of @(x)@ to ensure that the 'StableName' is correct first time,
-- which avoids to produce a tree bigger than needed.
--
-- Note that this function uses 'unsafePerformIO' instead of returning in 'IO',
-- this is apparently required to avoid infinite loops due to unstable 'StableName'
-- in compiled code, and sometimes also in ghci.
--
-- Note that maybe [pseq should be used here](https://gitlab.haskell.org/ghc/ghc/-/issues/2916).
makeSharingName :: a -> SharingName
makeSharingName :: a -> SharingName
makeSharingName !a
x = StableName a -> SharingName
forall a. StableName a -> SharingName
SharingName (StableName a -> SharingName) -> StableName a -> SharingName
forall a b. (a -> b) -> a -> b
$ IO (StableName a) -> StableName a
forall a. IO a -> a
unsafePerformIO (IO (StableName a) -> StableName a)
-> IO (StableName a) -> StableName a
forall a b. (a -> b) -> a -> b
$ a -> IO (StableName a)
forall a. a -> IO (StableName a)
makeStableName a
x

instance Eq SharingName where
  SharingName StableName a
x == :: SharingName -> SharingName -> Bool
== SharingName StableName a
y = StableName a -> StableName a -> Bool
forall a b. StableName a -> StableName b -> Bool
eqStableName StableName a
x StableName a
y
instance Hashable SharingName where
  hash :: SharingName -> Int
hash (SharingName StableName a
n) = StableName a -> Int
forall a. StableName a -> Int
hashStableName StableName a
n
  hashWithSalt :: Int -> SharingName -> Int
hashWithSalt Int
salt (SharingName StableName a
n) = Int -> StableName a -> Int
forall a. Hashable a => Int -> a -> Int
hashWithSalt Int
salt StableName a
n
{-
instance Show SharingName where
  showsPrec _ (SharingName n) = showHex (I# (unsafeCoerce# n))
-}

-- * Type 'ObserveSharing'
newtype ObserveSharing letName repr a = ObserveSharing { ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
unObserveSharing ::
  MT.ReaderT (HashSet SharingName)
             (MT.State (ObserveSharingState letName))
             (FinalizeSharing letName repr a) }

-- | Interpreter detecting some (Haskell embedded) @let@ definitions used at
-- least once and/or recursively, in order to replace them
-- with the 'shareable' and 'ref' combinators.
-- See [Type-safe observable sharing in Haskell](https://doi.org/10.1145/1596638.1596653)
--
-- Beware not to apply 'observeSharing' more than once on the same term
-- otherwise some 'shareable' introduced by the first call
-- would be removed by the second call.
observeSharing ::
  Eq letName =>
  Hashable letName =>
  Show letName =>
  ObserveSharing letName repr a ->
  WithSharing letName repr a
observeSharing :: ObserveSharing letName repr a -> WithSharing letName repr a
observeSharing (ObserveSharing ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
m) =
  let (FinalizeSharing letName repr a
fs, ObserveSharingState letName
st) = ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
-> HashSet SharingName
-> State
     (ObserveSharingState letName) (FinalizeSharing letName repr a)
forall r (m :: * -> *) a. ReaderT r m a -> r -> m a
MT.runReaderT ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
m HashSet SharingName
forall a. Monoid a => a
mempty State
  (ObserveSharingState letName) (FinalizeSharing letName repr a)
-> ObserveSharingState letName
-> (FinalizeSharing letName repr a, ObserveSharingState letName)
forall s a. State s a -> s -> (a, s)
`MT.runState`
        ObserveSharingState :: forall letName.
HashMap SharingName (letName, Int)
-> HashSet SharingName -> ObserveSharingState letName
ObserveSharingState
          { oss_refs :: HashMap SharingName (letName, Int)
oss_refs = HashMap SharingName (letName, Int)
forall k v. HashMap k v
HM.empty
          , oss_recs :: HashSet SharingName
oss_recs = HashSet SharingName
forall a. HashSet a
HS.empty
          } in
  let refs :: HashSet letName
refs = [letName] -> HashSet letName
forall a. (Eq a, Hashable a) => [a] -> HashSet a
HS.fromList ([letName] -> HashSet letName) -> [letName] -> HashSet letName
forall a b. (a -> b) -> a -> b
$
        (((letName, Int) -> [letName])
-> HashMap SharingName (letName, Int) -> [letName]
forall (t :: * -> *) m a.
(Foldable t, Monoid m) =>
(a -> m) -> t a -> m
`foldMap` ObserveSharingState letName -> HashMap SharingName (letName, Int)
forall letName.
ObserveSharingState letName -> HashMap SharingName (letName, Int)
oss_refs ObserveSharingState letName
st) (((letName, Int) -> [letName]) -> [letName])
-> ((letName, Int) -> [letName]) -> [letName]
forall a b. (a -> b) -> a -> b
$ (\(letName
letName, Int
refCount) ->
          if Int
refCount Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
> Int
0 then [letName
letName] else []) in
  --trace (show refs) $
  Writer (LetBindings letName repr) (repr a)
-> WithSharing letName repr a
forall w a. Writer w a -> (a, w)
MT.runWriter (Writer (LetBindings letName repr) (repr a)
 -> WithSharing letName repr a)
-> Writer (LetBindings letName repr) (repr a)
-> WithSharing letName repr a
forall a b. (a -> b) -> a -> b
$
    (ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> HashSet letName -> Writer (LetBindings letName repr) (repr a)
forall r (m :: * -> *) a. ReaderT r m a -> r -> m a
`MT.runReaderT` HashSet letName
refs) (ReaderT
   (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
 -> Writer (LetBindings letName repr) (repr a))
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> Writer (LetBindings letName repr) (repr a)
forall a b. (a -> b) -> a -> b
$
      FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
forall letName (repr :: * -> *) a.
FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing FinalizeSharing letName repr a
fs

-- ** Type 'SomeLet'
data SomeLet repr = forall a. SomeLet (repr a)

-- ** Type 'WithSharing'
type WithSharing letName repr a =
  (repr a, HM.HashMap letName (SomeLet repr))
{-
-- * Type 'WithSharing'
data WithSharing letName repr a = WithSharing
  { lets :: HM.HashMap letName (SomeLet repr)
  , body :: repr a
  }
mapWithSharing ::
  (forall v. repr v -> repr v) ->
  WithSharing letName repr a ->
  WithSharing letName repr a
mapWithSharing f ws = WithSharing
  { lets = (\(SomeLet repr) -> SomeLet (f repr)) <$> lets ws
  , body = f (body ws)
  }
-}

-- ** Type 'ObserveSharingState'
data ObserveSharingState letName = ObserveSharingState
  { ObserveSharingState letName -> HashMap SharingName (letName, Int)
oss_refs :: HashMap SharingName (letName, Int)
  , ObserveSharingState letName -> HashSet SharingName
oss_recs :: HashSet SharingName
    -- ^ TODO: unused so far, will it be useful somewhere at a later stage?
  }

observeSharingNode ::
  Eq letName =>
  Hashable letName =>
  Show letName =>
  Letable letName repr =>
  MakeLetName letName =>
  ObserveSharing letName repr a ->
  ObserveSharing letName repr a
observeSharingNode :: ObserveSharing letName repr a -> ObserveSharing letName repr a
observeSharingNode (ObserveSharing ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
m) = ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
-> ObserveSharing letName repr a
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
-> ObserveSharing letName repr a
ObserveSharing (ReaderT
   (HashSet SharingName)
   (State (ObserveSharingState letName))
   (FinalizeSharing letName repr a)
 -> ObserveSharing letName repr a)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
-> ObserveSharing letName repr a
forall a b. (a -> b) -> a -> b
$ do
  let nodeName :: SharingName
nodeName = ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
-> SharingName
forall a. a -> SharingName
makeSharingName ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
m
  ObserveSharingState letName
st <- StateT
  (ObserveSharingState letName)
  Identity
  (ObserveSharingState letName)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (ObserveSharingState letName)
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
MT.lift StateT
  (ObserveSharingState letName)
  Identity
  (ObserveSharingState letName)
forall (m :: * -> *) s. Monad m => StateT s m s
MT.get
  ((letName
letName, Maybe (letName, Int)
before), HashMap SharingName (letName, Int)
preds) <- Compose
  (ReaderT
     (HashSet SharingName) (State (ObserveSharingState letName)))
  ((,) (letName, Maybe (letName, Int)))
  (HashMap SharingName (letName, Int))
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     ((letName, Maybe (letName, Int)),
      HashMap SharingName (letName, Int))
forall k1 (f :: k1 -> *) k2 (g :: k2 -> k1) (a :: k2).
Compose f g a -> f (g a)
getCompose (Compose
   (ReaderT
      (HashSet SharingName) (State (ObserveSharingState letName)))
   ((,) (letName, Maybe (letName, Int)))
   (HashMap SharingName (letName, Int))
 -> ReaderT
      (HashSet SharingName)
      (State (ObserveSharingState letName))
      ((letName, Maybe (letName, Int)),
       HashMap SharingName (letName, Int)))
-> Compose
     (ReaderT
        (HashSet SharingName) (State (ObserveSharingState letName)))
     ((,) (letName, Maybe (letName, Int)))
     (HashMap SharingName (letName, Int))
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     ((letName, Maybe (letName, Int)),
      HashMap SharingName (letName, Int))
forall a b. (a -> b) -> a -> b
$ (Maybe (letName, Int)
 -> Compose
      (ReaderT
         (HashSet SharingName) (State (ObserveSharingState letName)))
      ((,) (letName, Maybe (letName, Int)))
      (Maybe (letName, Int)))
-> SharingName
-> HashMap SharingName (letName, Int)
-> Compose
     (ReaderT
        (HashSet SharingName) (State (ObserveSharingState letName)))
     ((,) (letName, Maybe (letName, Int)))
     (HashMap SharingName (letName, Int))
forall (f :: * -> *) k v.
(Functor f, Eq k, Hashable k) =>
(Maybe v -> f (Maybe v)) -> k -> HashMap k v -> f (HashMap k v)
HM.alterF (\Maybe (letName, Int)
before ->
    ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  ((letName, Maybe (letName, Int)), Maybe (letName, Int))
-> Compose
     (ReaderT
        (HashSet SharingName) (State (ObserveSharingState letName)))
     ((,) (letName, Maybe (letName, Int)))
     (Maybe (letName, Int))
forall k k1 (f :: k -> *) (g :: k1 -> k) (a :: k1).
f (g a) -> Compose f g a
Compose (ReaderT
   (HashSet SharingName)
   (State (ObserveSharingState letName))
   ((letName, Maybe (letName, Int)), Maybe (letName, Int))
 -> Compose
      (ReaderT
         (HashSet SharingName) (State (ObserveSharingState letName)))
      ((,) (letName, Maybe (letName, Int)))
      (Maybe (letName, Int)))
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     ((letName, Maybe (letName, Int)), Maybe (letName, Int))
-> Compose
     (ReaderT
        (HashSet SharingName) (State (ObserveSharingState letName)))
     ((,) (letName, Maybe (letName, Int)))
     (Maybe (letName, Int))
forall a b. (a -> b) -> a -> b
$ case Maybe (letName, Int)
before of
      Maybe (letName, Int)
Nothing -> do
        let letName :: letName
letName = IO letName -> letName
forall a. IO a -> a
unsafePerformIO (IO letName -> letName) -> IO letName -> letName
forall a b. (a -> b) -> a -> b
$ SharingName -> IO letName
forall letName. MakeLetName letName => SharingName -> IO letName
makeLetName SharingName
nodeName
        ((letName, Maybe (letName, Int)), Maybe (letName, Int))
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     ((letName, Maybe (letName, Int)), Maybe (letName, Int))
forall (m :: * -> *) a. Monad m => a -> m a
return ((letName
letName, Maybe (letName, Int)
before), (letName, Int) -> Maybe (letName, Int)
forall a. a -> Maybe a
Just (letName
letName, Int
0))
      Just (letName
letName, Int
refCount) -> do
        ((letName, Maybe (letName, Int)), Maybe (letName, Int))
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     ((letName, Maybe (letName, Int)), Maybe (letName, Int))
forall (m :: * -> *) a. Monad m => a -> m a
return ((letName
letName, Maybe (letName, Int)
before), (letName, Int) -> Maybe (letName, Int)
forall a. a -> Maybe a
Just (letName
letName, Int
refCount Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
1))
    ) SharingName
nodeName (ObserveSharingState letName -> HashMap SharingName (letName, Int)
forall letName.
ObserveSharingState letName -> HashMap SharingName (letName, Int)
oss_refs ObserveSharingState letName
st)
  HashSet SharingName
parentNames <- ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (HashSet SharingName)
forall (m :: * -> *) r. Monad m => ReaderT r m r
MT.ask
  if SharingName
nodeName SharingName -> HashSet SharingName -> Bool
forall a. (Eq a, Hashable a) => a -> HashSet a -> Bool
`HS.member` HashSet SharingName
parentNames
  then do
    StateT (ObserveSharingState letName) Identity ()
-> ReaderT
     (HashSet SharingName) (State (ObserveSharingState letName)) ()
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
MT.lift (StateT (ObserveSharingState letName) Identity ()
 -> ReaderT
      (HashSet SharingName) (State (ObserveSharingState letName)) ())
-> StateT (ObserveSharingState letName) Identity ()
-> ReaderT
     (HashSet SharingName) (State (ObserveSharingState letName)) ()
forall a b. (a -> b) -> a -> b
$ ObserveSharingState letName
-> StateT (ObserveSharingState letName) Identity ()
forall (m :: * -> *) s. Monad m => s -> StateT s m ()
MT.put ObserveSharingState letName
st
      { oss_refs :: HashMap SharingName (letName, Int)
oss_refs = HashMap SharingName (letName, Int)
preds
      , oss_recs :: HashSet SharingName
oss_recs = SharingName -> HashSet SharingName -> HashSet SharingName
forall a. (Eq a, Hashable a) => a -> HashSet a -> HashSet a
HS.insert SharingName
nodeName (ObserveSharingState letName -> HashSet SharingName
forall letName. ObserveSharingState letName -> HashSet SharingName
oss_recs ObserveSharingState letName
st)
      }
    FinalizeSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall (m :: * -> *) a. Monad m => a -> m a
return (FinalizeSharing letName repr a
 -> ReaderT
      (HashSet SharingName)
      (State (ObserveSharingState letName))
      (FinalizeSharing letName repr a))
-> FinalizeSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall a b. (a -> b) -> a -> b
$ Bool -> letName -> FinalizeSharing letName repr a
forall letName (repr :: * -> *) a.
Letable letName repr =>
Bool -> letName -> repr a
ref Bool
True letName
letName
  else do
    StateT (ObserveSharingState letName) Identity ()
-> ReaderT
     (HashSet SharingName) (State (ObserveSharingState letName)) ()
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
MT.lift (StateT (ObserveSharingState letName) Identity ()
 -> ReaderT
      (HashSet SharingName) (State (ObserveSharingState letName)) ())
-> StateT (ObserveSharingState letName) Identity ()
-> ReaderT
     (HashSet SharingName) (State (ObserveSharingState letName)) ()
forall a b. (a -> b) -> a -> b
$ ObserveSharingState letName
-> StateT (ObserveSharingState letName) Identity ()
forall (m :: * -> *) s. Monad m => s -> StateT s m ()
MT.put ObserveSharingState letName
st{ oss_refs :: HashMap SharingName (letName, Int)
oss_refs = HashMap SharingName (letName, Int)
preds }
    if Maybe (letName, Int) -> Bool
forall a. Maybe a -> Bool
isNothing Maybe (letName, Int)
before
      then (HashSet SharingName -> HashSet SharingName)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall r (m :: * -> *) a.
(r -> r) -> ReaderT r m a -> ReaderT r m a
MT.local (SharingName -> HashSet SharingName -> HashSet SharingName
forall a. (Eq a, Hashable a) => a -> HashSet a -> HashSet a
HS.insert SharingName
nodeName) (letName
-> FinalizeSharing letName repr a -> FinalizeSharing letName repr a
forall letName (repr :: * -> *) a.
Letable letName repr =>
letName -> repr a -> repr a
shareable letName
letName (FinalizeSharing letName repr a -> FinalizeSharing letName repr a)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
m)
      else FinalizeSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall (m :: * -> *) a. Monad m => a -> m a
return (FinalizeSharing letName repr a
 -> ReaderT
      (HashSet SharingName)
      (State (ObserveSharingState letName))
      (FinalizeSharing letName repr a))
-> FinalizeSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall a b. (a -> b) -> a -> b
$ Bool -> letName -> FinalizeSharing letName repr a
forall letName (repr :: * -> *) a.
Letable letName repr =>
Bool -> letName -> repr a
ref Bool
False letName
letName

type instance Derived (ObserveSharing letName repr) = FinalizeSharing letName repr
instance
  ( Letable letName repr
  , MakeLetName letName
  , Eq letName
  , Hashable letName
  , Show letName
  ) => LiftDerived (ObserveSharing letName repr) where
  liftDerived :: Derived (ObserveSharing letName repr) a
-> ObserveSharing letName repr a
liftDerived = ObserveSharing letName repr a -> ObserveSharing letName repr a
forall letName (repr :: * -> *) a.
(Eq letName, Hashable letName, Show letName, Letable letName repr,
 MakeLetName letName) =>
ObserveSharing letName repr a -> ObserveSharing letName repr a
observeSharingNode (ObserveSharing letName repr a -> ObserveSharing letName repr a)
-> (FinalizeSharing letName repr a
    -> ObserveSharing letName repr a)
-> FinalizeSharing letName repr a
-> ObserveSharing letName repr a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
-> ObserveSharing letName repr a
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
-> ObserveSharing letName repr a
ObserveSharing (ReaderT
   (HashSet SharingName)
   (State (ObserveSharingState letName))
   (FinalizeSharing letName repr a)
 -> ObserveSharing letName repr a)
-> (FinalizeSharing letName repr a
    -> ReaderT
         (HashSet SharingName)
         (State (ObserveSharingState letName))
         (FinalizeSharing letName repr a))
-> FinalizeSharing letName repr a
-> ObserveSharing letName repr a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. FinalizeSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall (m :: * -> *) a. Monad m => a -> m a
return
instance
  ( Letable letName repr
  , MakeLetName letName
  , Eq letName
  , Hashable letName
  , Show letName
  ) => LiftDerived1 (ObserveSharing letName repr) where
  liftDerived1 :: (Derived (ObserveSharing letName repr) a
 -> Derived (ObserveSharing letName repr) b)
-> ObserveSharing letName repr a -> ObserveSharing letName repr b
liftDerived1 Derived (ObserveSharing letName repr) a
-> Derived (ObserveSharing letName repr) b
f ObserveSharing letName repr a
x = ObserveSharing letName repr b -> ObserveSharing letName repr b
forall letName (repr :: * -> *) a.
(Eq letName, Hashable letName, Show letName, Letable letName repr,
 MakeLetName letName) =>
ObserveSharing letName repr a -> ObserveSharing letName repr a
observeSharingNode (ObserveSharing letName repr b -> ObserveSharing letName repr b)
-> ObserveSharing letName repr b -> ObserveSharing letName repr b
forall a b. (a -> b) -> a -> b
$ ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr b)
-> ObserveSharing letName repr b
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
-> ObserveSharing letName repr a
ObserveSharing (ReaderT
   (HashSet SharingName)
   (State (ObserveSharingState letName))
   (FinalizeSharing letName repr b)
 -> ObserveSharing letName repr b)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr b)
-> ObserveSharing letName repr b
forall a b. (a -> b) -> a -> b
$
    Derived (ObserveSharing letName repr) a
-> Derived (ObserveSharing letName repr) b
FinalizeSharing letName repr a -> FinalizeSharing letName repr b
f (FinalizeSharing letName repr a -> FinalizeSharing letName repr b)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr b)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall letName (repr :: * -> *) a.
ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
unObserveSharing ObserveSharing letName repr a
x
instance
  ( Letable letName repr
  , MakeLetName letName
  , Eq letName
  , Hashable letName
  , Show letName
  ) => LiftDerived2 (ObserveSharing letName repr) where
  liftDerived2 :: (Derived (ObserveSharing letName repr) a
 -> Derived (ObserveSharing letName repr) b
 -> Derived (ObserveSharing letName repr) c)
-> ObserveSharing letName repr a
-> ObserveSharing letName repr b
-> ObserveSharing letName repr c
liftDerived2 Derived (ObserveSharing letName repr) a
-> Derived (ObserveSharing letName repr) b
-> Derived (ObserveSharing letName repr) c
f ObserveSharing letName repr a
x ObserveSharing letName repr b
y = ObserveSharing letName repr c -> ObserveSharing letName repr c
forall letName (repr :: * -> *) a.
(Eq letName, Hashable letName, Show letName, Letable letName repr,
 MakeLetName letName) =>
ObserveSharing letName repr a -> ObserveSharing letName repr a
observeSharingNode (ObserveSharing letName repr c -> ObserveSharing letName repr c)
-> ObserveSharing letName repr c -> ObserveSharing letName repr c
forall a b. (a -> b) -> a -> b
$ ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr c)
-> ObserveSharing letName repr c
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
-> ObserveSharing letName repr a
ObserveSharing (ReaderT
   (HashSet SharingName)
   (State (ObserveSharingState letName))
   (FinalizeSharing letName repr c)
 -> ObserveSharing letName repr c)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr c)
-> ObserveSharing letName repr c
forall a b. (a -> b) -> a -> b
$
    Derived (ObserveSharing letName repr) a
-> Derived (ObserveSharing letName repr) b
-> Derived (ObserveSharing letName repr) c
FinalizeSharing letName repr a
-> FinalizeSharing letName repr b -> FinalizeSharing letName repr c
f (FinalizeSharing letName repr a
 -> FinalizeSharing letName repr b
 -> FinalizeSharing letName repr c)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr b -> FinalizeSharing letName repr c)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall letName (repr :: * -> *) a.
ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
unObserveSharing ObserveSharing letName repr a
x
      ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr b -> FinalizeSharing letName repr c)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr b)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr c)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> ObserveSharing letName repr b
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr b)
forall letName (repr :: * -> *) a.
ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
unObserveSharing ObserveSharing letName repr b
y
instance
  ( Letable letName repr
  , MakeLetName letName
  , Eq letName
  , Hashable letName
  , Show letName
  ) => LiftDerived3 (ObserveSharing letName repr) where
  liftDerived3 :: (Derived (ObserveSharing letName repr) a
 -> Derived (ObserveSharing letName repr) b
 -> Derived (ObserveSharing letName repr) c
 -> Derived (ObserveSharing letName repr) d)
-> ObserveSharing letName repr a
-> ObserveSharing letName repr b
-> ObserveSharing letName repr c
-> ObserveSharing letName repr d
liftDerived3 Derived (ObserveSharing letName repr) a
-> Derived (ObserveSharing letName repr) b
-> Derived (ObserveSharing letName repr) c
-> Derived (ObserveSharing letName repr) d
f ObserveSharing letName repr a
x ObserveSharing letName repr b
y ObserveSharing letName repr c
z = ObserveSharing letName repr d -> ObserveSharing letName repr d
forall letName (repr :: * -> *) a.
(Eq letName, Hashable letName, Show letName, Letable letName repr,
 MakeLetName letName) =>
ObserveSharing letName repr a -> ObserveSharing letName repr a
observeSharingNode (ObserveSharing letName repr d -> ObserveSharing letName repr d)
-> ObserveSharing letName repr d -> ObserveSharing letName repr d
forall a b. (a -> b) -> a -> b
$ ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr d)
-> ObserveSharing letName repr d
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr a)
-> ObserveSharing letName repr a
ObserveSharing (ReaderT
   (HashSet SharingName)
   (State (ObserveSharingState letName))
   (FinalizeSharing letName repr d)
 -> ObserveSharing letName repr d)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr d)
-> ObserveSharing letName repr d
forall a b. (a -> b) -> a -> b
$
    Derived (ObserveSharing letName repr) a
-> Derived (ObserveSharing letName repr) b
-> Derived (ObserveSharing letName repr) c
-> Derived (ObserveSharing letName repr) d
FinalizeSharing letName repr a
-> FinalizeSharing letName repr b
-> FinalizeSharing letName repr c
-> FinalizeSharing letName repr d
f (FinalizeSharing letName repr a
 -> FinalizeSharing letName repr b
 -> FinalizeSharing letName repr c
 -> FinalizeSharing letName repr d)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr b
      -> FinalizeSharing letName repr c
      -> FinalizeSharing letName repr d)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
forall letName (repr :: * -> *) a.
ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
unObserveSharing ObserveSharing letName repr a
x
      ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr b
   -> FinalizeSharing letName repr c
   -> FinalizeSharing letName repr d)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr b)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr c -> FinalizeSharing letName repr d)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> ObserveSharing letName repr b
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr b)
forall letName (repr :: * -> *) a.
ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
unObserveSharing ObserveSharing letName repr b
y
      ReaderT
  (HashSet SharingName)
  (State (ObserveSharingState letName))
  (FinalizeSharing letName repr c -> FinalizeSharing letName repr d)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr c)
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr d)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> ObserveSharing letName repr c
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr c)
forall letName (repr :: * -> *) a.
ObserveSharing letName repr a
-> ReaderT
     (HashSet SharingName)
     (State (ObserveSharingState letName))
     (FinalizeSharing letName repr a)
unObserveSharing ObserveSharing letName repr c
z
instance Letable letName (ObserveSharing letName repr) where
  shareable :: letName
-> ObserveSharing letName repr a -> ObserveSharing letName repr a
shareable = String
-> letName
-> ObserveSharing letName repr a
-> ObserveSharing letName repr a
forall a. HasCallStack => String -> a
error String
"[BUG]: observeSharing MUST NOT be applied twice"
  ref :: Bool -> letName -> ObserveSharing letName repr a
ref = String -> Bool -> letName -> ObserveSharing letName repr a
forall a. HasCallStack => String -> a
error String
"[BUG]: observeSharing MUST NOT be applied twice"
instance Letsable letName (ObserveSharing letName repr) where
  lets :: LetBindings letName (ObserveSharing letName repr)
-> ObserveSharing letName repr a -> ObserveSharing letName repr a
lets = String
-> LetBindings letName (ObserveSharing letName repr)
-> ObserveSharing letName repr a
-> ObserveSharing letName repr a
forall a. HasCallStack => String -> a
error String
"[BUG]: observeSharing MUST NOT be applied twice"

-- * Type 'FinalizeSharing'
-- | Remove 'shareable' when non-recursive or unused
-- or replace it by 'ref', moving 'shareable's to the top.
newtype FinalizeSharing letName repr a = FinalizeSharing { FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing ::
  MT.ReaderT (HS.HashSet letName)
    (MT.Writer (LetBindings letName repr))
      (repr a) }

-- ** Type 'LetBindings'
type LetBindings letName repr = HM.HashMap letName (SomeLet repr)

type instance Derived (FinalizeSharing _letName repr) = repr
instance
  ( Eq letName
  , Hashable letName
  ) => LiftDerived (FinalizeSharing letName repr) where
  liftDerived :: Derived (FinalizeSharing letName repr) a
-> FinalizeSharing letName repr a
liftDerived = ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> FinalizeSharing letName repr a
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> FinalizeSharing letName repr a
FinalizeSharing (ReaderT
   (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
 -> FinalizeSharing letName repr a)
-> (repr a
    -> ReaderT
         (HashSet letName) (Writer (LetBindings letName repr)) (repr a))
-> repr a
-> FinalizeSharing letName repr a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
forall (f :: * -> *) a. Applicative f => a -> f a
pure
instance
  ( Eq letName
  , Hashable letName
  ) => LiftDerived1 (FinalizeSharing letName repr) where
  liftDerived1 :: (Derived (FinalizeSharing letName repr) a
 -> Derived (FinalizeSharing letName repr) b)
-> FinalizeSharing letName repr a -> FinalizeSharing letName repr b
liftDerived1 Derived (FinalizeSharing letName repr) a
-> Derived (FinalizeSharing letName repr) b
f FinalizeSharing letName repr a
x = ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr b)
-> FinalizeSharing letName repr b
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> FinalizeSharing letName repr a
FinalizeSharing (ReaderT
   (HashSet letName) (Writer (LetBindings letName repr)) (repr b)
 -> FinalizeSharing letName repr b)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr b)
-> FinalizeSharing letName repr b
forall a b. (a -> b) -> a -> b
$ repr a -> repr b
Derived (FinalizeSharing letName repr) a
-> Derived (FinalizeSharing letName repr) b
f (repr a -> repr b)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr b)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
forall letName (repr :: * -> *) a.
FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing FinalizeSharing letName repr a
x
instance
  ( Eq letName
  , Hashable letName
  ) => LiftDerived2 (FinalizeSharing letName repr) where
  liftDerived2 :: (Derived (FinalizeSharing letName repr) a
 -> Derived (FinalizeSharing letName repr) b
 -> Derived (FinalizeSharing letName repr) c)
-> FinalizeSharing letName repr a
-> FinalizeSharing letName repr b
-> FinalizeSharing letName repr c
liftDerived2 Derived (FinalizeSharing letName repr) a
-> Derived (FinalizeSharing letName repr) b
-> Derived (FinalizeSharing letName repr) c
f FinalizeSharing letName repr a
x FinalizeSharing letName repr b
y = ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr c)
-> FinalizeSharing letName repr c
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> FinalizeSharing letName repr a
FinalizeSharing (ReaderT
   (HashSet letName) (Writer (LetBindings letName repr)) (repr c)
 -> FinalizeSharing letName repr c)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr c)
-> FinalizeSharing letName repr c
forall a b. (a -> b) -> a -> b
$
    repr a -> repr b -> repr c
Derived (FinalizeSharing letName repr) a
-> Derived (FinalizeSharing letName repr) b
-> Derived (FinalizeSharing letName repr) c
f (repr a -> repr b -> repr c)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> ReaderT
     (HashSet letName)
     (Writer (LetBindings letName repr))
     (repr b -> repr c)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
forall letName (repr :: * -> *) a.
FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing FinalizeSharing letName repr a
x
      ReaderT
  (HashSet letName)
  (Writer (LetBindings letName repr))
  (repr b -> repr c)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr b)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr c)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> FinalizeSharing letName repr b
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr b)
forall letName (repr :: * -> *) a.
FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing FinalizeSharing letName repr b
y
instance
  ( Eq letName
  , Hashable letName
  ) => LiftDerived3 (FinalizeSharing letName repr) where
  liftDerived3 :: (Derived (FinalizeSharing letName repr) a
 -> Derived (FinalizeSharing letName repr) b
 -> Derived (FinalizeSharing letName repr) c
 -> Derived (FinalizeSharing letName repr) d)
-> FinalizeSharing letName repr a
-> FinalizeSharing letName repr b
-> FinalizeSharing letName repr c
-> FinalizeSharing letName repr d
liftDerived3 Derived (FinalizeSharing letName repr) a
-> Derived (FinalizeSharing letName repr) b
-> Derived (FinalizeSharing letName repr) c
-> Derived (FinalizeSharing letName repr) d
f FinalizeSharing letName repr a
x FinalizeSharing letName repr b
y FinalizeSharing letName repr c
z = ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr d)
-> FinalizeSharing letName repr d
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> FinalizeSharing letName repr a
FinalizeSharing (ReaderT
   (HashSet letName) (Writer (LetBindings letName repr)) (repr d)
 -> FinalizeSharing letName repr d)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr d)
-> FinalizeSharing letName repr d
forall a b. (a -> b) -> a -> b
$
    repr a -> repr b -> repr c -> repr d
Derived (FinalizeSharing letName repr) a
-> Derived (FinalizeSharing letName repr) b
-> Derived (FinalizeSharing letName repr) c
-> Derived (FinalizeSharing letName repr) d
f (repr a -> repr b -> repr c -> repr d)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> ReaderT
     (HashSet letName)
     (Writer (LetBindings letName repr))
     (repr b -> repr c -> repr d)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
forall letName (repr :: * -> *) a.
FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing FinalizeSharing letName repr a
x
      ReaderT
  (HashSet letName)
  (Writer (LetBindings letName repr))
  (repr b -> repr c -> repr d)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr b)
-> ReaderT
     (HashSet letName)
     (Writer (LetBindings letName repr))
     (repr c -> repr d)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> FinalizeSharing letName repr b
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr b)
forall letName (repr :: * -> *) a.
FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing FinalizeSharing letName repr b
y
      ReaderT
  (HashSet letName)
  (Writer (LetBindings letName repr))
  (repr c -> repr d)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr c)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr d)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> FinalizeSharing letName repr c
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr c)
forall letName (repr :: * -> *) a.
FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing FinalizeSharing letName repr c
z
instance
  ( Letable letName repr
  , Eq letName
  , Hashable letName
  , Show letName
  ) => Letable letName (FinalizeSharing letName repr) where
  shareable :: letName
-> FinalizeSharing letName repr a -> FinalizeSharing letName repr a
shareable letName
name FinalizeSharing letName repr a
x = ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> FinalizeSharing letName repr a
forall letName (repr :: * -> *) a.
ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> FinalizeSharing letName repr a
FinalizeSharing (ReaderT
   (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
 -> FinalizeSharing letName repr a)
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> FinalizeSharing letName repr a
forall a b. (a -> b) -> a -> b
$ do
    HashSet letName
refs <- ReaderT
  (HashSet letName)
  (Writer (LetBindings letName repr))
  (HashSet letName)
forall (m :: * -> *) r. Monad m => ReaderT r m r
MT.ask
    if letName
name letName -> HashSet letName -> Bool
forall a. (Eq a, Hashable a) => a -> HashSet a -> Bool
`HS.member` HashSet letName
refs
      -- This 'shareable' is 'ref'erenced, move it into the result,
      -- to put it in scope even when some 'ref' to it exists outside of 'x'
      -- (which can happen when a sub-expression is shared),
      -- and replace it by a 'ref'.
      then do
        let (repr a
repr, LetBindings letName repr
defs) = Writer (LetBindings letName repr) (repr a)
-> (repr a, LetBindings letName repr)
forall w a. Writer w a -> (a, w)
MT.runWriter (Writer (LetBindings letName repr) (repr a)
 -> (repr a, LetBindings letName repr))
-> Writer (LetBindings letName repr) (repr a)
-> (repr a, LetBindings letName repr)
forall a b. (a -> b) -> a -> b
$ ReaderT
  (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
-> HashSet letName -> Writer (LetBindings letName repr) (repr a)
forall r (m :: * -> *) a. ReaderT r m a -> r -> m a
MT.runReaderT (FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
forall letName (repr :: * -> *) a.
FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing FinalizeSharing letName repr a
x) HashSet letName
refs
        WriterT (LetBindings letName repr) Identity ()
-> ReaderT (HashSet letName) (Writer (LetBindings letName repr)) ()
forall (t :: (* -> *) -> * -> *) (m :: * -> *) a.
(MonadTrans t, Monad m) =>
m a -> t m a
MT.lift (WriterT (LetBindings letName repr) Identity ()
 -> ReaderT
      (HashSet letName) (Writer (LetBindings letName repr)) ())
-> WriterT (LetBindings letName repr) Identity ()
-> ReaderT (HashSet letName) (Writer (LetBindings letName repr)) ()
forall a b. (a -> b) -> a -> b
$ LetBindings letName repr
-> WriterT (LetBindings letName repr) Identity ()
forall (m :: * -> *) w. Monad m => w -> WriterT w m ()
MT.tell (LetBindings letName repr
 -> WriterT (LetBindings letName repr) Identity ())
-> LetBindings letName repr
-> WriterT (LetBindings letName repr) Identity ()
forall a b. (a -> b) -> a -> b
$ letName
-> SomeLet repr
-> LetBindings letName repr
-> LetBindings letName repr
forall k v.
(Eq k, Hashable k) =>
k -> v -> HashMap k v -> HashMap k v
HM.insert letName
name (repr a -> SomeLet repr
forall (repr :: * -> *) a. repr a -> SomeLet repr
SomeLet repr a
repr) LetBindings letName repr
defs
        repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
forall (m :: * -> *) a. Monad m => a -> m a
return (repr a
 -> ReaderT
      (HashSet letName) (Writer (LetBindings letName repr)) (repr a))
-> repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
forall a b. (a -> b) -> a -> b
$ Bool -> letName -> repr a
forall letName (repr :: * -> *) a.
Letable letName repr =>
Bool -> letName -> repr a
ref Bool
False letName
name
      -- Remove 'shareable'.
      else
        FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
forall letName (repr :: * -> *) a.
FinalizeSharing letName repr a
-> ReaderT
     (HashSet letName) (Writer (LetBindings letName repr)) (repr a)
unFinalizeSharing FinalizeSharing letName repr a
x

-- * Class 'Letsable'
class Letsable letName repr where
  -- | @('lets' defs x)@ let-binds @(defs)@ in @(x)@.
  lets :: LetBindings letName repr -> repr a -> repr a
  lets LetBindings letName repr
defs = (Derived repr a -> Derived repr a) -> repr a -> repr a
forall (repr :: * -> *) a b.
LiftDerived1 repr =>
(Derived repr a -> Derived repr b) -> repr a -> repr b
liftDerived1 (LetBindings letName (Derived repr)
-> Derived repr a -> Derived repr a
forall letName (repr :: * -> *) a.
Letsable letName repr =>
LetBindings letName repr -> repr a -> repr a
lets ((\(SomeLet repr a
val) -> Derived repr a -> SomeLet (Derived repr)
forall (repr :: * -> *) a. repr a -> SomeLet repr
SomeLet (repr a -> Derived repr a
forall (repr :: * -> *) a.
Derivable repr =>
repr a -> Derived repr a
derive repr a
val)) (SomeLet repr -> SomeLet (Derived repr))
-> LetBindings letName repr -> LetBindings letName (Derived repr)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> LetBindings letName repr
defs))
  default lets ::
    Derivable repr =>
    FromDerived1 (Letsable letName) repr =>
    LetBindings letName repr -> repr a -> repr a
{-
-- | Not used but can be written nonetheless.
instance
  ( Letsable letName repr
  , Eq letName
  , Hashable letName
  , Show letName
  ) => Letsable letName (FinalizeSharing letName repr) where
  lets defs x = FinalizeSharing $ do
    ds <- traverse (\(SomeLet v) -> do
      r <- unFinalizeSharing v
      return (SomeLet r)
      ) defs
    MT.lift $ MT.tell ds
    unFinalizeSharing x
-}