Control.Monad.Except.Util

Utilities related to the mtl package.

Assertions

assert :: (IsString e, MonadError e m) => e -> Bool -> m ()

Make an assertion.

deny :: (IsString e, MonadError e m) => e -> Bool -> m ()

Make a denial.

Input/Output

tryIO :: (IsString e, MonadError e m, MonadIO m) => IO a -> m a

Attempt an IO action.