Skip to content

Latest commit

 

History

History
45 lines (31 loc) · 876 Bytes

MonadThrow.md

File metadata and controls

45 lines (31 loc) · 876 Bytes
Raw

MonadThrow

The MonadThrow typeclass provides the ability to exit a computation with an error value.

Parent

The MonadThrow typeclass extends the Monad typeclass.

API

The MonadThrow typeclass add a single method to the Monad interface, providing the ability of exiting a computation with an error value.

interface MonadThrow extends Monad
{
    /**
     * @param E $e
     * @return F<A>
     */
    public function throwError($e);
}

Its simplified signature is

throwError :: E -> F<A>

Laws

The MonadThrow typeclass should satisfy one addition laws with respect to the ones required by the Functor, Apply, Applicative and Monad typeclasses.

Left zero

$monadThrow->bind($monadThrow->throwError($e), $f) == $monadThrow->throwError($e)

Implemented instances

  • EitherMonadThrow
  • MaybeMonadThrow