Examples

Documentation

readIntV1 :: MonadError (Variant e) m => CouldBeF e Text => String -> m Int

A simple function that throws an error.

The type is the one that is inferred by GHC.

readIntV2 :: MonadError (Variant e) m => e `CouldBe` Text => String -> m Int

A simple function that throws an error.

This is the same as before, but we can rewrite constraint on e differently.

readIntV3 :: e `CouldBe` Text => String -> ExceptT (Variant e) Identity Int

A simple function that throws an error.

We can also use ExceptT

readIntV4 :: e `CouldBe` Text => String -> ExceptT (Variant e) IO Int

A simple IO function that throws an error.

We can also use ExceptT of IO.

readIntV5 :: MonadError (Variant e) m => MonadIO m => e `CouldBe` Text => String -> m Int

A simple function that throws an error.

Or use MonadIO instead of IO directly.

readIntV6 :: MonadIO m => e `CouldBe` Text => String -> ExceptT (Variant e) m Int

A simple function that throws an error.

Or use MonadIO with ExceptT.

data NotAnInteger

Constructors

NotAnInteger

data NotPositive

Constructors

NotPositive

readPositiveInt1 :: MonadIO m => e `CouldBe` NotAnInteger => e `CouldBe` NotPositive => String -> ExceptT (Variant e) m Int

A simple function can throw two errors

example1 :: e `CouldBe` Text => String -> ExceptT (Variant e) IO Int

example2 :: String -> ExceptT (Variant e) IO Int

example3 :: String -> IO Int

data FileNotFound

Constructors

FileNotFound

data FileNotReadable

Constructors

FileNotReadable

data Errors1

Constructors

Errors1NotPositive NotPositive

Errors1NotAnInteger NotAnInteger

example4 :: MonadIO m => e `CouldBe` Errors1 => String -> ExceptT (Variant e) m Int

example5 :: MonadIO m => String -> ExceptT Errors1 m Int

example6 :: MonadIO m => String -> m (Either Errors1 Int)

example7 :: MonadIO m => e `CouldBe` NotPositive => e `CouldBe` NotAnInteger => String -> ExceptT (Variant e) m Int

example8 :: MonadIO m => e `CouldBe` NotPositive => e `CouldBe` NotAnInteger => String -> ExceptT (Variant e) m Int

example9 :: MonadIO m => e `CouldBe` NotPositive => e `CouldBe` NotAnInteger => String -> ExceptT (Variant e) m Int

example10 :: MonadIO m => e `CouldBe` NotPositive => e `CouldBe` NotAnInteger => String -> ExceptT (Variant e) m Int

example11 :: MonadIO m => MonadCatch m => e `CouldBe` IOException => ExceptT (Variant e) m String

example12 :: MonadIO m => MonadCatch m => e `CouldBe` IOException => ExceptT (Variant e) m String