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control-monad-exception-0.4.1: Explicitly typed, checked exceptions with stack traces

The control-monad-exception package

This package provides explicitly typed, checked exceptions as a library. /Example/

> data Expr = Add Expr Expr | Div Expr Expr | Val Double > eval (Val x) = return x > eval (Add a1 a2) = do > v1 <- eval a1 > v2 <- eval a2 > let sum = v1 + v2 > if sum < v1 || sum < v2 then throw SumOverflow else return sum > eval (Div a1 a2) = do > v1 <- eval a1 > v2 <- eval a2 > if v2 == 0 then throw DivideByZero else return (v1 / v2)

> data DivideByZero = DivideByZero deriving (Show, Typeable) > data SumOverflow = SumOverflow deriving (Show, Typeable)

> instance Exception DivideByZero > instance Exception SumOverflow

GHCi infers the following types

> eval :: (Throws DivideByZero l, Throws SumOverflow l) => Expr -> EM l Double > eval `catch` \ (e::DivideByZero) -> return (-1) :: Throws SumOverflow l => Expr -> EM l Double > runEM(eval `catch` \ (e::SomeException) -> return (-1)) :: Expr -> Double New in version 0.4: * (optionally) Unchecked exceptions (with 'UncaughtException') * Exception stack traces (with 'WithSrcLoc'). For example > f () = $withLocTH $ throw MyException > g a = $withLocTH $ f a > main = runEMT $ $withLocTH $ do > g () `catchWithSrcLoc` \loc MyException -> lift $ putStrLn (showExceptionWithTrace loc MyException) Running @main@ produces the output: > *Main> main > MyException > in Main.docatch.hs: (12,6) > Main.docatch.hs: (11,7)

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• control-monad-exception-0.4.1.tar.gz (Cabal source package)
• package description (included in the package)

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