-- ghc -package lang TestException.hs -o TestException && ./TestException
module Main where
	{
	import IORef;
	import qualified Exception;

	getPureException :: a -> IO (Maybe Exception.Exception);
	getPureException a = (Exception.catch (seq a (return Nothing)) (return . Just));

	showIOS :: String -> IO String -> IO ();
	showIOS s ios = do
		{
		putStr (s ++ ":	");
		mpe <- getPureException ios;
		case mpe of
			{
			Just pe -> putStrLn ("pure exception ("++ (show pe) ++")");
			Nothing -> Exception.catch (Prelude.catch (do
				{
				result <- ios;
				mrpe <- getPureException result;
				case mrpe of
					{
					Just pe -> putStrLn ("returned pure exception ("++ (show pe) ++")");
					Nothing -> putStrLn ("value ("++ (show result) ++")");
					};
				}) (\e -> putStrLn ("IO failure (" ++ (show e) ++")")) )
				(\e -> putStrLn ("IO other exception (" ++ (show e) ++")"));
			};
		};

	evaluate' :: a -> IO a;
	evaluate' a = a `seq` return a;

	evaluate'' :: a -> IO a;
	evaluate'' a = (Exception.catch (seq a (return a)) (\e -> fail (show e)));

	main :: IO ();
	main = do
		{
		putStrLn "* value";
		showIOS "return text"						(return "text");
		showIOS "return undefined >> return text"	(return undefined >> return "text");
		putStrLn "";

		putStrLn "* returned pure exception";
		showIOS "return undefined"					(return undefined);
		showIOS "return (seq undefined text)"		(return (seq undefined "text"));
		showIOS "return () >> return undefined"		(return () >> return undefined);
		showIOS "return undefined >>= return"		(return undefined >>= return);
		putStrLn "";

		putStrLn "* IO failure";
		showIOS "fail text"							(fail "text");
		showIOS "ioError (userError text)"			(ioError (userError "text"));
		putStrLn "";

		putStrLn "* IO other exception";
		showIOS "undefined >> return text"			(undefined >> return "text");
		showIOS "return () >> undefined"			(return () >> undefined);
		showIOS "ioError (ErrorCall text)"			(ioError (Exception.ErrorCall "text"));
		showIOS "ioError (AssertionFailed text)"	(ioError (Exception.AssertionFailed "text"));
		putStrLn "";

		putStrLn "* pure exception";
		showIOS "undefined"							undefined;
		showIOS "seq undefined (return text)"		(seq undefined (return "text"));
		showIOS "seq undefined (return undefined)"	(seq undefined (return undefined));
		showIOS "error text"						(error "text");
		showIOS "throw (userError text)"			(Exception.throw (userError "text"));
		showIOS "throw (ErrorCall text)"			(Exception.throw (Exception.ErrorCall "text"));
		showIOS "throw (AssertionFailed text)"		(Exception.throw (Exception.AssertionFailed "text"));
		putStrLn "";

		putStrLn "* evaluate functions";
		showIOS "evaluate undefined"				(Exception.evaluate undefined);
		showIOS "evaluate' undefined"				(evaluate' undefined);
		showIOS "evaluate'' undefined"				(evaluate'' undefined);
		};
	}