Trait funlib::Applicative

pub trait Applicative<B>: Functor<B> {
    fn pure_(value: B) -> Self::M
    where
        Self: HKT<B, A = B>;
    fn ap<F>(&self, f: <Self as HKT<F>>::M) -> <Self as HKT<B>>::M
    where
        F: Fn(&<Self as HKT<B>>::A) -> B,
        Self: HKT<F>;
}

Applicative type class

Required methods

fn pure_(value: B) -> Self::M where
    Self: HKT<B, A = B>, 

Lift values into the context of the Functor

Examples

use funlib::Applicative;
let s1 = Option::<i8>::pure_(10);
let s2 = Option::pure_("hi");
let v = Vec::pure_(1);

fn ap<F>(&self, f: <Self as HKT<F>>::M) -> <Self as HKT<B>>::M where
    F: Fn(&<Self as HKT<B>>::A) -> B,
    Self: HKT<F>, 

Apply function is almost the same as Functor map. but the function isn’t A => B but A<F => B>

Examples

use funlib::Applicative;
fn double(i: &i32) -> i32 { i * 2  }
let f: &dyn Fn(&i32) -> i32 = &|x| x * 2;
assert_eq!(Some(4), Some(2).ap(Some(f)));
assert_eq!(Some(4), Some(2).ap(Some(&double)));

Implementations on Foreign Types

impl<A, B> Applicative<B> for Option<A>

fn pure_(b: B) -> <Self as HKT<B>>::M

fn ap<F>(&self, of: <Self as HKT<F>>::M) -> Option<B> where
    F: Fn(&A) -> B, 

impl<A, B> Applicative<B> for Box<A>

fn pure_(b: B) -> <Self as HKT<B>>::M

fn ap<F>(&self, of: <Self as HKT<F>>::M) -> Box<B> where
    F: Fn(&A) -> B, 

impl<A, B> Applicative<B> for Rc<A>

fn pure_(b: B) -> <Self as HKT<B>>::M

fn ap<F>(&self, of: <Self as HKT<F>>::M) -> Rc<B> where
    F: Fn(&A) -> B, 

impl<A, B> Applicative<B> for Vec<A>

fn pure_(b: B) -> <Self as HKT<B>>::M

fn ap<F>(&self, of: <Self as HKT<F>>::M) -> Vec<B> where
    F: Fn(&A) -> B, 

Implementors