Control.Effect.Error

An effect modelling catchable failure with a polymorphic error type, the combination of Throw and Catch.

This effect is similar to the traditional MonadError typeclass, though it allows the presence of multiple Error effects in a given effect stack. It offers precise exception handling, rather than the dynamic exception hierarchy provided by the exceptions package. The fused-effects-exceptions package may be more suitable for handling dynamic/impure effect handling.

Predefined carriers:

• Control.Carrier.Error.Church.

• Control.Carrier.Error.Either.

• Control.Monad.Trans.Except.

• If Error e is the last effect in a stack, it can be interpreted directly to an Either e.