From 46a0812ad03559178dc3b2f16dab9c6b66b4eae1 Mon Sep 17 00:00:00 2001
From: Rose Hogenson <rosehogenson@posteo.net>
Date: Fri, 12 Jan 2024 23:31:55 -0800
Subject: Introduce new helper functions for creating ropes.

---
 src/rope.rs | 59 +++++++++++++++++++++++++++--------------------------------
 1 file changed, 27 insertions(+), 32 deletions(-)

(limited to 'src/rope.rs')

diff --git a/src/rope.rs b/src/rope.rs
index 1eda553..3d72833 100644
--- a/src/rope.rs
+++ b/src/rope.rs
@@ -87,15 +87,21 @@ impl Rope {
         }))
     }
 
-    fn branch(children: Rc<[Rope]>) -> Rope {
-        let mut len = 0;
-        let mut lines = 0;
-        for c in children.iter() {
-            len += c.len();
-            lines += c.lines();
-        }
+    fn two(x: Rope, y: Rope) -> Rope {
+        let len = x.len() + y.len();
+        let lines = x.lines() + y.lines();
         Rope(Node::Branch(Branch {
-            children,
+            children: Rc::new([x, y]),
+            len,
+            lines,
+        }))
+    }
+
+    fn three(x: Rope, y: Rope, z: Rope) -> Rope {
+        let len = x.len() + y.len() + z.len();
+        let lines = x.lines() + y.lines() + z.lines();
+        Rope(Node::Branch(Branch {
+            children: Rc::new([x, y, z]),
             len,
             lines,
         }))
@@ -134,28 +140,21 @@ impl Rope {
             ) {
                 Insert::Node(new_child) => {
                     if b.children.len() == 2 {
-                        return Insert::Node(Rope::branch(Rc::new([
-                            b.children[0].clone(),
-                            new_child,
-                        ])));
+                        return Insert::Node(Rope::two(b.children[0].clone(), new_child));
                     }
-                    return Insert::Node(Rope::branch(Rc::new([
+                    return Insert::Node(Rope::three(
                         b.children[0].clone(),
                         b.children[1].clone(),
                         new_child,
-                    ])));
+                    ));
                 }
                 Insert::Split(child1, child2) => {
                     if b.children.len() == 2 {
-                        return Insert::Node(Rope::branch(Rc::new([
-                            b.children[0].clone(),
-                            child1,
-                            child2,
-                        ])));
+                        return Insert::Node(Rope::three(b.children[0].clone(), child1, child2));
                     }
                     return Insert::Split(
-                        Rope::branch(Rc::new([b.children[0].clone(), b.children[1].clone()])),
-                        Rope::branch(Rc::new([child1, child2])),
+                        Rope::two(b.children[0].clone(), b.children[1].clone()),
+                        Rope::two(child1, child2),
                     );
                 }
             }
@@ -166,25 +165,21 @@ impl Rope {
         match self.concat_height(self_height, &b.children[0], other_height - 1) {
             Insert::Node(new_child) => {
                 if b.children.len() == 2 {
-                    return Insert::Node(Rope::branch(Rc::new([new_child, b.children[1].clone()])));
+                    return Insert::Node(Rope::two(new_child, b.children[1].clone()));
                 }
-                Insert::Node(Rope::branch(Rc::new([
+                Insert::Node(Rope::three(
                     new_child,
                     b.children[1].clone(),
                     b.children[2].clone(),
-                ])))
+                ))
             }
             Insert::Split(child1, child2) => {
                 if b.children.len() == 2 {
-                    return Insert::Node(Rope::branch(Rc::new([
-                        child1,
-                        child2,
-                        b.children[1].clone(),
-                    ])));
+                    return Insert::Node(Rope::three(child1, child2, b.children[1].clone()));
                 }
                 Insert::Split(
-                    Rope::branch(Rc::new([child1, child2])),
-                    Rope::branch(Rc::new([b.children[1].clone(), b.children[2].clone()])),
+                    Rope::two(child1, child2),
+                    Rope::two(b.children[1].clone(), b.children[2].clone()),
                 )
             }
         }
@@ -206,7 +201,7 @@ impl Rope {
         }
         match self.concat_height(self.height(), other, other.height()) {
             Insert::Node(r) => r,
-            Insert::Split(l, r) => Rope::branch(Rc::new([l, r])),
+            Insert::Split(l, r) => Rope::two(l, r),
         }
     }
 
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