Remove unnecessary length field.

1 files changed, 9 insertions, 11 deletions

diff --git a/src/rope.rs b/src/rope.rs
index f26457c..320cd14 100644
--- a/src/rope.rs
+++ b/src/rope.rs
@@ -8,7 +8,6 @@ use std::rc::Rc;
 const MAX_NODE_SIZE: usize = 4;
 
 struct Branch {
-    len: usize,
     left: Rc<Node>,
     right: Rc<Node>,
 }
@@ -19,13 +18,6 @@ enum Node {
 }
 
 impl Node {
-    fn len(&self) -> usize {
-        return match self {
-            Node::Leaf(v) => v.len(),
-            Node::Branch(b) => b.len,
-        };
-    }
-
     fn write(&self, out: &mut Vec<u8>) {
         match self {
             Node::Leaf(v) => {
@@ -37,6 +29,13 @@ impl Node {
             }
         }
     }
+
+    fn empty(&self) -> bool {
+        return match self {
+            Node::Leaf(v) => v.len() == 0,
+            _ => false,
+        };
+    }
 }
 
 impl Display for Node {
@@ -52,14 +51,13 @@ pub struct Rope(Rc<Node>);
 impl Rope {
     fn concat(self, Rope(other): Rope) -> Rope {
         let Rope(me) = self;
-        if me.len() == 0 {
+        if me.empty() {
             return Rope(other);
         }
-        if other.len() == 0 {
+        if other.empty() {
             return Rope(me);
         }
         return Rope(Rc::new(Node::Branch(Branch {
-            len: me.len() + other.len(),
             left: me,
             right: other,
         })));