Function applicative_fmap 

pub fn applicative_fmap<'a, T, B, F>(
    applicative: T,
    f: F,
) -> <T as Functor<'a, B>>::Mapped
where
    T: Applicative<'a, B>,
    F: 'a + Send + FnMut(<T as Functor<'a, B>>::Inner) -> B,

Generic implementation of Functor::fmap for Applicative functors

This generic implementation can be used to define Functor::fmap based on Applicative::apply and Pure::pure when the functor is applicative. A more specific implementation might be more efficient though.