Add utility constructors for Event and UpdateArgs for easy 0.0 delta …

…time. Modify RepeatSequence doc code to make use of them.

bonsai/src/behavior.rs

@@ -65,18 +65,20 @@ pub enum Behavior<A> {
     ///use bonsai_bt::Event;
     ///
     ///#[derive(Clone, Debug)]
+    ///
     ///enum Ex { A, B, C }
+    ///
     ///let rs = RepeatSequence(
     ///    Box::new(Action(Ex::A)),
     ///    vec![Action(Ex::B), Action(Ex::C)],
     ///);
-    ///let mut bt = BT::new(rs, ());
+    ///
     ///let (SUCCESS, FAILURE, RUNNING ) = ((Success, 0.0), (Failure, 0.0), (Running, 0.0));
     ///
-    ///let e: Event = UpdateArgs { dt: 0.0 }.into();
+    ///let mut bt = BT::new(rs, ());
     ///
     ///let mut i = 0;
-    ///let status = bt.tick(&e, &mut |args: ActionArgs<Event, Ex>, blackboard| {
+    ///let status = bt.tick(&Event::zero_dt_args(), &mut |args: ActionArgs<Event, Ex>, _| {
     ///    match args.action {
     ///        Ex::A => {
     ///            i += 1;

bonsai/src/event.rs

@@ -9,6 +9,13 @@ pub struct UpdateArgs {
     pub dt: f64,
 }
 
+impl UpdateArgs {
+    /// Creates [UpdateArgs] with `0.0` delta time.
+    pub fn zero_dt() -> UpdateArgs {
+        Self { dt: 0.0 }
+    }
+}
+
 /// Models loop events.
 #[derive(Copy, Clone, Debug, PartialEq, PartialOrd, serde::Deserialize, serde::Serialize)]
 pub enum Loop {
@@ -30,6 +37,12 @@ pub enum Event {
     /// Events that commonly used by event loops.
     Loop(Loop),
 }
+impl Event {
+    /// Creates [Event] from [UpdateArgs] with `0.0` delta time.
+    pub fn zero_dt_args() -> Self {
+        UpdateArgs::zero_dt().into()
+    }
+}
 
 /// When the application state should be updated.
 pub trait UpdateEvent: Sized {