fay-0.14.0.0: tests/mutableReference.hs

-- | Mutable references.

{-# LANGUAGE EmptyDataDecls    #-}

import           FFI
import           Prelude

main :: Fay ()
main = do
  ref <- newRef "Hello, World!"
  x <- readRef ref
  writeRef ref "Hai!"
  readRef ref >>= putStrLn

data Ref a
instance Show (Ref a)
instance Foreign a => Foreign (Ref a)

newRef :: Foreign a => a -> Fay (Ref a)
newRef = ffi "new Fay$$Ref(%1)"

writeRef :: Foreign a => Ref a -> a -> Fay ()
writeRef = ffi "Fay$$writeRef(%1,%2)"

readRef :: Foreign a => Ref a -> Fay a
readRef = ffi "Fay$$readRef(%1)"