Modulepolysemy-1.9.2.0Haskell2010

Polysemy.NonDet

Effect

1 declaration

datadata NonDet (m :: Type -> Type) a

An effect corresponding to the Alternative typeclass.

3 declarations

valuerunNonDet :: Alternative f => Sem (NonDet ': r) a -> Sem r (f a)

Run a NonDet effect in terms of some underlying Alternative f.

valuerunNonDetMaybe :: Sem (NonDet ': r) a -> Sem r (Maybe a)

Run a NonDet effect in terms of an underlying Maybe

Unlike runNonDet, uses of <|> will not execute the second branch at all if the first option succeeds.

valuenonDetToError :: Member (Error e) r => e -> Sem (NonDet ': r) a -> Sem r a

Transform a NonDet effect into an Error e effect, through providing an exception that empty may be mapped to.

This allows <|> to handle throws of the Error e effect.