{-# LANGUAGE GADTs #-} {- | Provides an effect to cull choices in a given nondeterministic context. This effect is used in concert with 'Control.Effect.NonDet.NonDet'. Computations run inside a call to 'cull' will return at most one result. Predefined carriers: * "Control.Carrier.Cull.Church" @since 0.1.2.0 -} module Control.Effect.Cull ( -- * Cull effect Cull(..) , cull -- * Re-exports , Algebra , Has , run ) where import Control.Algebra -- | 'Cull' effects are used with 'Control.Effect.Choose' to provide control over branching. -- -- @since 0.1.2.0 data Cull m k where Cull :: m a -> Cull m a -- | Cull nondeterminism in the argument, returning at most one result. -- -- @ -- 'cull' ('pure' a 'Control.Effect.Choose.<|>' m) 'Control.Effect.Choose.<|>' n = 'pure' a 'Control.Effect.Choose.<|>' n -- @ -- -- @since 0.1.2.0 cull :: Has Cull sig m => m a -> m a cull :: forall (sig :: (* -> *) -> * -> *) (m :: * -> *) a. Has Cull sig m => m a -> m a cull m a m = Cull m a -> m a forall (eff :: (* -> *) -> * -> *) (sig :: (* -> *) -> * -> *) (m :: * -> *) a. (Member eff sig, Algebra sig m) => eff m a -> m a send (m a -> Cull m a forall (m :: * -> *) a. m a -> Cull m a Cull m a m) {-# INLINE cull #-}