{-# LANGUAGE
      DeriveDataTypeable,
      QuasiQuotes #-}
module Basis.MVar (entries) where

import Data.Typeable (Typeable)
import BasisUtils
import Syntax
import Util
import Value (Value, Valuable(..))

import qualified Loc
import qualified Syntax.Notable
import qualified Syntax.Decl

import qualified Control.Concurrent.MVar as MV

newtype MVar = MVar { unMVar :: MV.MVar Value }
  deriving (Eq, Typeable)

instance Valuable MVar where
  veq = (==)
  vpprPrec _ _ = text "#<mvar>"

entries :: [Entry Raw]
entries  = [
    dec [$dc| type `a mvar qualifier U |],
    fun "new" -: [$ty| all `a. `a -> `a mvar |]
      -= liftM MVar . MV.newMVar,
    fun "newEmpty"
                 -: [$ty| all `a. unit -> `a mvar |]
      -= \() -> MVar `liftM` MV.newEmptyMVar,
    fun "take"
                 -: [$ty| all `a. `a mvar -> `a |]
      -= MV.takeMVar . unMVar,
    fun "put"
                 -: [$ty| all `a. `a mvar -> `a -> unit |]
      -= MV.putMVar . unMVar,
    fun "read"
                 -: [$ty| all 'a. 'a mvar -> 'a |] -- important!
      -= MV.readMVar . unMVar,
    fun "swap"
                 -: [$ty| all `a. `a mvar -> `a -> `a |]
      -= MV.swapMVar . unMVar,
    fun "tryTake"
                 -: [$ty| all `a. `a mvar -> `a option |]
      -= MV.tryTakeMVar . unMVar,
    fun "tryPut"
                 -: [$ty| all `a. `a mvar -> `a -> bool |]
      -= MV.tryPutMVar . unMVar,
    fun "isEmpty"
                 -: [$ty| all `a. `a mvar -> bool |]
      -= MV.isEmptyMVar . unMVar,
    fun "callWith"
                 -: [$ty| all `a `b. `a mvar -> (`a -> `b) -> `b |]
      -= \mv callback -> MV.withMVar (unMVar mv) (vapp callback),
    fun "modify_"
                 -: [$ty| all `a. `a mvar -> (`a -> `a) -> unit |]
      -= \mv callback -> MV.modifyMVar_ (unMVar mv) (vapp callback),
    fun "modify"
                 -: [$ty| all `a `b. `a mvar -> (`a -> `a * `b) -> `b |]
      -= \mv callback -> MV.modifyMVar (unMVar mv) $ \v -> do
                           result <- vapp callback v
                           (vprjM result :: IO (Value, Value))
  ]