Trait fmap::NestedMonad

source ·

pub trait NestedMonad<'a, A>where
    Self: Monad<'a, <Self::InnerMonad as Functor<'a, A>>::Inner> + Functor<'a, <Self::InnerMonad as Functor<'a, A>>::Inner, Inner = A, Mapped = A>,
    A: 'a,{
    type InnerMonad: Functor<'a, A>;

    // Provided method
    fn mjoin(self) -> A { ... }
}

Expand description

Nested monad that can be joined

This trait is automatically implemented for nested monads with type parameter A being the inner monad.

Examples

use fmap::NestedMonad;

fn my_mjoin<'a, M: NestedMonad<'a, A>, A>(m: M) -> A
where
    M: NestedMonad<'a, A>,
    A: 'a,
{
    m.bind(|x| x)
}

let nested = vec![vec![1, 3], vec![2, 9, 9]];
assert_eq!(my_mjoin(nested.clone()), vec![1, 3, 2, 9, 9]);
assert_eq!(nested.mjoin(), vec![1, 3, 2, 9, 9]);