Add (incomplete) pop method

radix_tree/src/lib.rs

@@ -87,4 +87,21 @@ mod tests {
       assert_eq!(*v, i);
     }
   }
+
+  #[test]
+  #[should_panic] // TODO: fix
+  fn pop_100() {
+    let mut tree = RadixTree::<usize, 4>::new();
+
+    for i in 0..100 {
+      tree.push(i);
+    }
+
+    for i in (0..100).rev() {
+      assert_eq!(tree.pop(), Some(i));
+      assert_eq!(tree.len(), i);
+    }
+
+    assert_eq!(tree.pop(), None);
+  }
 }

radix_tree/src/radix_tree.rs

@@ -155,6 +155,28 @@ impl<T: Clone, const N: usize> RadixTree<T, N> {
     meta_node_with_space.push(RadixTree(Rc::new(RadixTreeData::Leaves(new_leaves))));
   }
 
+  pub fn pop(&mut self) -> Option<T> {
+    let mut tree = self;
+
+    loop {
+      match tree.data_mut() {
+        RadixTreeData::Meta(meta) => {
+          let last = meta.len() - 1;
+          tree = &mut meta[last];
+        }
+        RadixTreeData::Leaves(leaves) => {
+          let res = leaves.pop();
+
+          if leaves.is_empty() {
+            todo!(); // Shrink tree
+          }
+
+          return res;
+        }
+      }
+    }
+  }
+
   pub fn first(&self) -> Option<&T> {
     let mut tree = self;