Function async_std::stream::successors

pub fn successors<F, T>(first: Option<T>, succ: F) -> Successors<F, T> where
    F: FnMut(&T) -> Option<T>, 

Creates a new stream where to produce each new element a closure is called with the previous value.

Examples

use async_std::prelude::*;
use async_std::stream;

let mut s = stream::successors(Some(22), |&val| Some(val + 1));

assert_eq!(s.next().await, Some(22));
assert_eq!(s.next().await, Some(23));
assert_eq!(s.next().await, Some(24));
assert_eq!(s.next().await, Some(25));