Macro altern

macro_rules! altern {
    ($($params:expr $(,)?)*) => { ... };
}

The altern! macro provides a convenient syntax for creating an Altern iterator.

Syntax

The macro takes a variable number of iterator expressions, separated by commas. It then constructs an Altern instance and adds each provided iterator using the add method.

Example

use combin_iterator::altern;
let vec1 = vec![1, 4, 7, 9];
let vec2 = vec![2, 5];
let vec3 = vec![3, 6, 8];
let iter = altern!(vec1.iter(), vec2.iter(), vec3.iter());

assert_eq!(iter.collect::<Vec<_>>(), vec![&1, &2, &3, &4, &5, &6, &7, &8, &9]);

Expand into

From the code before, altern! expand into:

let vec1 = vec![1, 4, 7, 9];
let vec2 = vec![2, 5];
let vec3 = vec![3, 6, 8];
let iter = {
   let capacity = 1 + (1 + (1 + 0));
   let mut vec_altern = combin_iterator::altern::VecAltern::with_capacity(
       capacity,
   );
   vec_altern.add(vec1.iter());
   vec_altern.add(vec2.iter());
   vec_altern.add(vec3.iter());
   vec_altern
};

assert_eq!(iter.collect::<Vec<_>>(), vec![&1, &2, &3, &4, &5, &6, &7, &8, &9]);