{-# OPTIONS_GHC -fno-warn-orphans #-}
-{-# OPTIONS_GHC -XNoImplicitPrelude -funbox-strict-fields #-}
+{-# OPTIONS_GHC -XNoImplicitPrelude -funbox-strict-fields -XBangPatterns #-}
{-# OPTIONS_HADDOCK hide #-}
-----------------------------------------------------------------------------
-- |
-- > evaluate x = (return $! x) >>= return
--
evaluate :: a -> IO a
-evaluate a = IO $ \s -> case a `seq` () of () -> (# s, a #)
- -- NB. can't write
- -- a `seq` (# s, a #)
- -- because we can't have an unboxed tuple as a function argument
+evaluate a = IO $ \s -> let !va = a in (# s, va #) -- NB. see #2273
-{-# OPTIONS_GHC -XNoImplicitPrelude #-}
+{-# OPTIONS_GHC -XNoImplicitPrelude -XBangPatterns #-}
-----------------------------------------------------------------------------
-- |
-- Module : Prelude
#ifndef __HUGS__
infixr 0 $!
+#endif
-- -----------------------------------------------------------------------------
-- Miscellaneous functions
-- | Strict (call-by-value) application, defined in terms of 'seq'.
($!) :: (a -> b) -> a -> b
+#ifdef __GLASGOW_HASKELL__
+f $! x = let !vx = x in f vx -- see #2273
+#elif !defined(__HUGS__)
f $! x = x `seq` f x
#endif