Function map 

pub fn map<A, B>(
    transform: impl Fn(A) -> B + Clone + 'static,
) -> impl Fn(Option<A>) -> Option<B>

Free map on Option for function composition. Equivalent to Swift’s map<A, B>(_ transform: @escaping (A) -> B) -> (A?) -> B?

Examples

use overture_core::options::map;

let double = map(|x: i32| x * 2);
assert_eq!(double(Some(5)), Some(10));
assert_eq!(double(None), None);