wip: cursor gravity mode

lib-nested-core/src/edit_tree/cursor.rs

@@ -4,6 +4,14 @@ use {
 
 //<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
 
+enum GravityMode {
+    // tries to maintain a set distance from bottom
+    Gravity(usize),
+
+    // keeps equal distance from root
+    Floating
+}
+
 #[derive(Clone, Eq, PartialEq, Debug)]
 pub struct TreeCursor {
     pub leaf_mode: ListCursorMode,

lib-nested-core/src/editors/list/editor.rs

@@ -17,14 +17,13 @@ use {
 
 pub struct ListEditor {
     pub cursor: SingletonBuffer<ListCursor>,
-
-    // todo: (?) remove RwLock<..> around NestedNode ??
     pub data: VecBuffer< Arc<RwLock<EditTree>> >,
 
     pub spillbuf: Arc<RwLock<Vec<Arc<RwLock<EditTree>>>>>,
 
     pub(super) addr_port: OuterViewPort<dyn SequenceView<Item = isize>>,
     pub(super) mode_port: OuterViewPort<dyn SingletonView<Item = ListCursorMode>>,
+//  pub(super) grav_port: OuterViewPort<dyn SingletonView<Item = isize>>,
 
     depth: OuterViewPort<dyn SingletonView<Item = usize>>,