Control.Carrier.Empty.Church

Run an Empty effect, returning the first continuation for empty programs and applying the second to successful results.

runEmpty j k empty = j

runEmpty j k (pure a) = k a

Run an Empty effect, discarding its result.

This is convenient for using empty to signal early returns without needing to know whether control exited normally or not.

evalEmpty = runEmpty (pure ()) (const (pure ()))

Run an Empty effect, replacing its result with a Bool indicating whether control exited normally.

This is convenient for using empty to signal early returns when all you need to know is whether control exited normally or not, and not what value it exited with.

execEmpty = runEmpty (pure False) (const (pure True))

execEmpty (pure a) = pure True

execEmpty empty = pure False