Implement pure version of `todos` example :tada:

The `Widget` trait in `iced_pure` needed to change a bit to make the
implementation of `Element::map` possible.

Specifically, the `children` method has been split into `diff` and
`children_state`.

1 files changed, 6 insertions, 2 deletions

diff --git a/pure/src/widget/row.rs b/pure/src/widget/row.rs
index 147a0850..ec7e144c 100644
--- a/pure/src/widget/row.rs
+++ b/pure/src/widget/row.rs
@@ -85,8 +85,12 @@ where
         Box::new(())
     }
 
-    fn children(&self) -> &[Element<Message, Renderer>] {
-        &self.children
+    fn diff(&self, tree: &mut Tree) {
+        tree.diff_children(&self.children)
+    }
+
+    fn children_state(&self) -> Vec<Tree> {
+        self.children.iter().map(Tree::new).collect()
     }
 
     fn width(&self) -> Length {