shithub: MicroHs

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Fix evaluate and throwIO

--- a/lib/Control/Exception.hs

+++ b/lib/Control/Exception.hs

@@ -77,17 +77,17 @@

   unsafePerformIO (catch (evaluate v)

                          (\x -> throwIO (f x)))

--- XXX This isn't right.  It should return an IO action.

+-- Evaluate a when executed, not when evaluated

 evaluate :: a -> IO a

-evaluate a = seq a (return a)

+evaluate a = seq a (return ()) >> return a

-

 try :: forall a e . Exception e => IO a -> IO (Either e a)

 try ioa = catch (fmap Right ioa) (return . Left)

--- XXX This isn't right.  It should return an IO action.

+-- Throw an exception when executed, not when evaluated

 throwIO :: forall a e . Exception e => e -> IO a

-throwIO e = throw e

+throwIO e = bad >> bad   -- we never reacj the second 'bad'

+  where bad = throw e

 onException :: IO a -> IO b -> IO a

 onException io what =

-- 

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