feat(ecs): add start event

3 files changed, 14 insertions, 1 deletions

diff --git a/ecs/src/event.rs b/ecs/src/event.rs
index 6a4c3a8..93d4545 100644
--- a/ecs/src/event.rs
+++ b/ecs/src/event.rs
@@ -6,6 +6,8 @@ use seq_macro::seq;
 
 pub trait Event: Debug + 'static {}
 
+pub mod start;
+
 /// The ID of a [`Event`].
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Id
diff --git a/ecs/src/event/start.rs b/ecs/src/event/start.rs
new file mode 100644
index 0000000..248dd50
--- /dev/null
+++ b/ecs/src/event/start.rs
@@ -0,0 +1,7 @@
+use crate::event::Event;
+
+/// Start event.
+#[derive(Debug, Clone, Copy)]
+pub struct Start;
+
+impl Event for Start {}
diff --git a/ecs/src/lib.rs b/ecs/src/lib.rs
index cf2f198..0da8b71 100644
--- a/ecs/src/lib.rs
+++ b/ecs/src/lib.rs
@@ -13,6 +13,7 @@ use crate::actions::Action;
 use crate::component::storage::Storage as ComponentStorage;
 use crate::component::{Component, Id as ComponentId, Sequence as ComponentSequence};
 use crate::entity::Uid as EntityUid;
+use crate::event::start::Start as StartEvent;
 use crate::event::{Event, Id as EventId, Ids, Sequence as EventSequence};
 use crate::extension::{Collector as ExtensionCollector, Extension};
 use crate::lock::Lock;
@@ -195,7 +196,8 @@ impl World
             .make_archetype_lookup_entries();
     }
 
-    /// A event loop which runs until a stop is issued with [`Flags::stop`].
+    /// A event loop which runs until a stop is issued with [`Flags::stop`]. Before the
+    /// loop begins, [`StartEvent`] is emitted.
     ///
     /// # Panics
     /// Will panic if a internal lock cannot be acquired.
@@ -203,6 +205,8 @@ impl World
     {
         self.prepare();
 
+        self.emit(StartEvent);
+
         let event_seq = EventSeq::ids();
 
         loop {