From ef6e87270c7b840a00e665fbdb5c10225563e754 Mon Sep 17 00:00:00 2001
From: Andrzej Rybczak <andrzej@rybczak.net>
Date: Wed, 4 Sep 2024 07:04:14 +0200
Subject: [PATCH] Add Effectful.Prim.IORef

---
 effectful/CHANGELOG.md                |  1 +
 effectful/effectful.cabal             |  1 +
 effectful/src/Effectful/Prim/IORef.hs | 72 +++++++++++++++++++++++++++
 3 files changed, 74 insertions(+)
 create mode 100644 effectful/src/Effectful/Prim/IORef.hs

diff --git a/effectful/CHANGELOG.md b/effectful/CHANGELOG.md
index 2b7b6e7..cb20e50 100644
--- a/effectful/CHANGELOG.md
+++ b/effectful/CHANGELOG.md
@@ -8,6 +8,7 @@
   `Effectful.Labeled.Writer`.
 * Add `throwErrorWith` and `throwError_` to `Effectful.Error.Static` and
   `Effectful.Error.Dynamic`.
+* Add `Effectful.Prim.IORef`.
 * **Breaking changes**:
   - `localSeqLend`, `localLend`, `localSeqBorrow` and `localBorrow` now take a
     list of effects instead of a single one.
diff --git a/effectful/effectful.cabal b/effectful/effectful.cabal
index 965a7ab..c52cdfe 100644
--- a/effectful/effectful.cabal
+++ b/effectful/effectful.cabal
@@ -96,6 +96,7 @@ library
                      Effectful.FileSystem.IO.ByteString.Builder
                      Effectful.FileSystem.IO.ByteString.Lazy
                      Effectful.FileSystem.IO.File
+                     Effectful.Prim.IORef
                      Effectful.Process
                      Effectful.Temporary
                      Effectful.Timeout
diff --git a/effectful/src/Effectful/Prim/IORef.hs b/effectful/src/Effectful/Prim/IORef.hs
new file mode 100644
index 0000000..34b1684
--- /dev/null
+++ b/effectful/src/Effectful/Prim/IORef.hs
@@ -0,0 +1,72 @@
+-- | Lifted "Data.IORef".
+--
+-- /Note:/ it requires 'Prim' because @MutVar@ from the @primitive@ library is a
+-- generalization of 'IORef'.
+--
+-- @since 2.4.0.0
+module Effectful.Prim.IORef
+  ( -- * Effect
+    Prim
+
+    -- ** Handlers
+  , runPrim
+
+    -- * IORef
+  , IORef
+  , newIORef
+  , readIORef
+  , writeIORef
+  , modifyIORef
+  , modifyIORef'
+  , atomicModifyIORef
+  , atomicModifyIORef'
+  , atomicWriteIORef
+  , mkWeakIORef
+  ) where
+
+import Data.IORef (IORef)
+import Data.IORef qualified as Ref
+import System.Mem.Weak (Weak)
+
+import Effectful
+import Effectful.Dispatch.Static
+import Effectful.Dispatch.Static.Primitive
+import Effectful.Prim
+
+-- | Lifted 'Ref.newIORef'.
+newIORef :: Prim :> es => a -> Eff es (IORef a)
+newIORef = unsafeEff_ . Ref.newIORef
+
+-- | Lifted 'Ref.readIORef'.
+readIORef :: Prim :> es => IORef a -> Eff es a
+readIORef = unsafeEff_ . Ref.readIORef
+
+-- | Lifted 'Ref.writeIORef'.
+writeIORef :: Prim :> es => IORef a -> a -> Eff es ()
+writeIORef var = unsafeEff_ . Ref.writeIORef var
+
+-- | Lifted 'Ref.modifyIORef'.
+modifyIORef :: Prim :> es => IORef a -> (a -> a) -> Eff es ()
+modifyIORef var = unsafeEff_ . Ref.modifyIORef var
+
+-- | Lifted 'Ref.modifyIORef''.
+modifyIORef' :: Prim :> es => IORef a -> (a -> a) -> Eff es ()
+modifyIORef' var = unsafeEff_ . Ref.modifyIORef' var
+
+-- | Lifted 'Ref.atomicModifyIORef'.
+atomicModifyIORef :: Prim :> es => IORef a -> (a -> (a, b)) -> Eff es b
+atomicModifyIORef var = unsafeEff_ . Ref.atomicModifyIORef var
+
+-- | Lifted 'Ref.atomicModifyIORef''.
+atomicModifyIORef' :: Prim :> es => IORef a -> (a -> (a, b)) -> Eff es b
+atomicModifyIORef' var = unsafeEff_ . Ref.atomicModifyIORef' var
+
+-- | Lifted 'Ref.atomicWriteIORef''.
+atomicWriteIORef :: Prim :> es => IORef a -> a -> Eff es ()
+atomicWriteIORef var = unsafeEff_ . Ref.atomicWriteIORef var
+
+-- | Lifted 'Ref.mkWeakIORef'.
+mkWeakIORef :: Prim :> es => IORef a -> Eff es () -> Eff es (Weak (IORef a))
+mkWeakIORef var f = unsafeEff $ \es -> do
+  -- The finalizer can run at any point and in any thread.
+  Ref.mkWeakIORef var . unEff f =<< cloneEnv es