module EVM.Demand (demand) where

import Control.DeepSeq (NFData, force)
import Control.Exception.Base (evaluate)
import Control.Monad.IO.Class (MonadIO, liftIO)

-- | This is an easy way to force full evaluation of a value inside of
-- the IO monad, being essentially just the composition of @evaluate@
-- and @force@.
demand :: (MonadIO m, NFData a) => a -> m ()
demand :: a -> m ()
demand x :: a
x = do
  a
_ <- IO a -> m a
forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO (a -> IO a
forall a. a -> IO a
evaluate (a -> a
forall a. NFData a => a -> a
force a
x))
  () -> m ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()