Function tool::compose

pub fn compose<A, B, C, F, G>(
    f: F, 
    g: G
) -> impl Fn(A) -> C where
    G: Fn(A) -> B,
    F: Fn(B) -> C, 

Compose two functions.

Takes functions f and g and returns f ∘ g = |a: A| f(g(a)).