Resource

src/main.rs

@@ -5,7 +5,7 @@ pub struct GamarjobaPlugin;
 impl Plugin for GamarjobaPlugin {
     fn build(&self, app: &mut App) {
         app.add_startup_system(add_people)
-            .add_system(gamarjoba)
+            .insert_resource(GreetTimer(Timer::from_seconds(2.0, TimerMode::Repeating)))
             .add_system(greetings);
     }
     
@@ -25,16 +25,17 @@ fn add_people(mut commands: Commands) {
     commands.spawn((Person, Name("Mak'lazi Heyorem".into())));
 }
 
-fn greetings(query: Query<&Name, With<Person>>) {
+#[derive(Resource)]
+struct GreetTimer(Timer);
+
+fn greetings(query: Query<&Name, With<Person>>, time: Res<Time>, mut timer: ResMut<GreetTimer>) {
+    if timer.0.tick(time.delta()).just_finished() {
         for name in &query {
             println!("Gamarjoba, {}", name.0)
         }
-
+    }
 }
 
-fn gamarjoba() {
-    println!("Gamarjoba, munde!");
-}
 
 fn main() {
     App::new()