From e4550aaab29466905b5d84d9080d3ae73eea77e3 Mon Sep 17 00:00:00 2001
From: Carter Anderson <mcanders1@gmail.com>
Date: Mon, 9 Mar 2020 02:08:27 -0700
Subject: [PATCH] tweak add_children

---
 examples/parenting.rs    |  4 ++--
 examples/ui.rs           |  4 ++--
 src/ecs/world_builder.rs | 17 +++++++----------
 3 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/examples/parenting.rs b/examples/parenting.rs
index f6e9d0fbce..20b934d1cf 100644
--- a/examples/parenting.rs
+++ b/examples/parenting.rs
@@ -38,9 +38,9 @@ fn setup(world: &mut World, resources: &mut Resources) {
             ..Default::default()
         })
         .add(Rotator)
-        .add_children(|child_builder| {
+        .add_children(|builder| {
             // cube
-            child_builder.add_entity(MeshEntity {
+            builder.add_entity(MeshEntity {
                 mesh: cube_handle,
                 material: StandardMaterial {
                     albedo: math::vec4(0.5, 0.4, 0.3, 1.0).into(),
diff --git a/examples/ui.rs b/examples/ui.rs
index 1c1fff5406..d334060cbe 100644
--- a/examples/ui.rs
+++ b/examples/ui.rs
@@ -111,8 +111,8 @@ fn setup(world: &mut World, resources: &mut Resources) {
                 math::vec4(0.1, 0.1, 1.0, 1.0),
             ),
         })
-        .add_children(|child_builder| {
-            child_builder.add_entity(UiEntity {
+        .add_children(|builder| {
+            builder.add_entity(UiEntity {
                 node: Node::new(
                     math::vec2(0.0, 0.0),
                     Anchors::new(0.0, 1.0, 0.0, 1.0),
diff --git a/src/ecs/world_builder.rs b/src/ecs/world_builder.rs
index 4ce21b2fad..039b3c1b1f 100644
--- a/src/ecs/world_builder.rs
+++ b/src/ecs/world_builder.rs
@@ -72,18 +72,15 @@ impl<'a> WorldBuilder<'a> {
         self
     }
 
-    pub fn add_children(self, build_children: impl Fn(WorldBuilder) -> WorldBuilder) -> Self {
-        let mut child_builder = WorldBuilder {
-            world: self.world,
-            parent_entity: self.current_entity,
-            current_entity: None,
-        };
+    pub fn add_children(mut self, build_children: impl Fn(WorldBuilder) -> WorldBuilder) -> Self {
+        self.parent_entity = self.current_entity;
+        self.current_entity = None;
 
-        child_builder = build_children(child_builder);
+        self = build_children(self);
 
-        child_builder.current_entity = child_builder.parent_entity;
-        child_builder.parent_entity = None;
-        child_builder
+        self.current_entity = self.parent_entity;
+        self.parent_entity = None;
+        self
     }
 
     fn add_parent_to_current_entity(&mut self) {