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35 lines
879 B
Idris
35 lines
879 B
Idris
module Data.IORef
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-- Implemented externally
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-- e.g., in Scheme, passed around as a box
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data Mut : Type -> Type where [external]
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%extern prim__newIORef : forall a . a -> (1 x : %World) -> IORes (Mut a)
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%extern prim__readIORef : forall a . Mut a -> (1 x : %World) -> IORes a
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%extern prim__writeIORef : forall a . Mut a -> (1 val : a) -> (1 x : %World) -> IORes ()
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export
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data IORef : Type -> Type where
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MkRef : Mut a -> IORef a
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export
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newIORef : a -> IO (IORef a)
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newIORef val
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= do m <- primIO (prim__newIORef val)
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pure (MkRef m)
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export
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readIORef : IORef a -> IO a
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readIORef (MkRef m) = primIO (prim__readIORef m)
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export
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writeIORef : IORef a -> (1 val : a) -> IO ()
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writeIORef (MkRef m) val = primIO (prim__writeIORef m val)
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export
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modifyIORef : IORef a -> (a -> a) -> IO ()
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modifyIORef ref f
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= do val <- readIORef ref
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writeIORef ref (f val)
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