Struct ContF 

pub struct ContF<R>(/* private fields */);

A contravariant functor type constructor: Of<A> = Box<dyn Fn(A) -> R>.

This is the “Op” or “Cont” functor, generalizing PredicateF (which is ContF<bool>). It is contravariant: given f: B -> A, we get ContF<R>::Of<A> -> ContF<R>::Of<B> by pre-composing with f.

ContF<R> is self-adjoint as a contravariant functor, giving rise to the continuation monad (A -> R) -> R via ContF<R> . ContF<R>.

Trait Implementations

impl<R> Contravariant for ContF<R>

where R: 'static,

Available on crate features std or alloc only.

fn contramap<A, B>( fa: <ContF<R> as HKT>::Of<A>, f: impl Fn(B) -> A + 'static, ) -> <ContF<R> as HKT>::Of<B>

where A: 'static,

impl<R> ContravariantAdjunction<ContF<R>, ContF<R>> for ContAdj<R>

where R: 'static,

Available on crate features std or alloc only.

fn unit<A>(a: A) -> Box<dyn Fn(Box<dyn Fn(A) -> R>) -> R>

where A: Clone + 'static,

unit: A -> G(F(A))

fn counit<B>(b: B) -> Box<dyn Fn(Box<dyn Fn(B) -> R>) -> R>

where B: Clone + 'static,

counit: B -> F(G(B))

impl<R> HKT for ContF<R>

where R: 'static,

Available on crate features std or alloc only.

type Of<T> = Box<dyn Fn(T) -> R>