2 files changed, 28 insertions, 23 deletions

diff --git a/src/main.rs b/src/main.rs
index bb3797d..10d7647 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -29,7 +29,7 @@ fn main() {
         println!("Usage: edit <filename>");
         std::process::exit(1);
     }
-    if let Err(err) = edit(&args[0]) {
+    if let Err(err) = edit(&args[1]) {
         println!("FAIL: {}", err);
         std::process::exit(1);
     }
diff --git a/src/rope.rs b/src/rope.rs
index 437d5e3..f26457c 100644
--- a/src/rope.rs
+++ b/src/rope.rs
@@ -4,7 +4,8 @@ use std::io::{ErrorKind, Read};
 use std::path::Path;
 use std::rc::Rc;
 
-const MAX_NODE_SIZE: usize = 512;
+// Set to a small value to help identify bugs in the implementation.
+const MAX_NODE_SIZE: usize = 4;
 
 struct Branch {
     len: usize,
@@ -17,40 +18,37 @@ enum Node {
     Branch(Branch),
 }
 
-impl Display for Node {
-    fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
+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(s) => {
-                return write!(f, "{}", String::from_utf8_lossy(s));
+            Node::Leaf(v) => {
+                out.extend(v);
             }
             Node::Branch(b) => {
-                if let Err(err) = write!(f, "{}", b.left) {
-                    return Err(err);
-                }
-                return write!(f, "{}", b.right);
+                b.left.write(out);
+                b.right.write(out);
             }
         }
     }
 }
 
-impl Node {
-    fn len(&self) -> usize {
-        return match self {
-            Node::Leaf(v) => v.len(),
-            Node::Branch(b) => b.len,
-        };
+impl Display for Node {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
+        let mut buf = Vec::new();
+        self.write(&mut buf);
+        return write!(f, "{}", String::from_utf8_lossy(&buf));
     }
 }
 
 pub struct Rope(Rc<Node>);
 
-impl Display for Rope {
-    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
-        let Rope(n) = self;
-        return write!(f, "{}", n);
-    }
-}
-
 impl Rope {
     fn concat(self, Rope(other): Rope) -> Rope {
         let Rope(me) = self;
@@ -94,3 +92,10 @@ impl Rope {
         return Ok(rope);
     }
 }
+
+impl Display for Rope {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
+        let Rope(n) = self;
+        return write!(f, "{}", n);
+    }
+}