use bevy::prelude::*;
use conditional_commands::*;

#[derive(Component)]
struct Even;

#[derive(Component)]
struct Odd;

fn exclusive_system(world: &mut World) {
    for n in 0..10 {
        world
            .spawn_empty()
            .insert_if_else(n % 2 == 0, || Even, || Odd);
    }
}

fn count_components(evens_query: Query<With<Even>>, odds_query: Query<With<Odd>>) {
    println!(
        "Counted {} entities with an Even component.",
        evens_query.iter().count()
    );
    println!(
        "Counted {} entities with an Odd component.",
        odds_query.iter().count()
    );
}

fn main() {
    App::new()
        .add_startup_system(exclusive_system)
        .add_system(count_components)
        .run();
}