Implement Home, End, PgUp, and PgDn.

1 files changed, 9 insertions, 8 deletions

diff --git a/src/rope.rs b/src/rope.rs
index 737d949..8bda5af 100644
--- a/src/rope.rs
+++ b/src/rope.rs
@@ -84,7 +84,7 @@ impl Rope {
         Rope(Node::Leaf(Leaf {
             unsafe_buf: Some(Rc::from(buf)),
             start: 0,
-            end: u16::try_from(buf.len()).expect("I just checked the length, it should be ok"),
+            end: u16::try_from(buf.len()).expect("buf.len() <= MAX_NODE_SIZE"),
         }))
     }
 
@@ -291,6 +291,9 @@ impl Rope {
     }
 
     pub fn line(&self, n: usize) -> Rope {
+        if n > self.lines() {
+            panic!("Line index {} out of range 0..={}", n, self.lines());
+        }
         self.slice(self.line_start(n), self.line_end(n)).clone()
     }
 
@@ -327,13 +330,11 @@ impl Rope {
             return self.clone();
         }
         match self {
-            Rope(Node::Leaf(l)) => {
-                Rope(Node::Leaf(Leaf{
-                    unsafe_buf: l.unsafe_buf.clone(),
-                    start: l.start+u16::try_from(start).expect("index.start should be less than MAX_NODE_SIZE since self is a leaf"),
-                    end: l.start+u16::try_from(end).expect("index.end should be less than or equal to MAX_NODE_SIZE since self is a leaf"),
-                }))
-            }
+            Rope(Node::Leaf(l)) => Rope(Node::Leaf(Leaf {
+                unsafe_buf: l.unsafe_buf.clone(),
+                start: l.start + u16::try_from(start).expect("start <= self.len()"),
+                end: l.start + u16::try_from(end).expect("end <= self.len()"),
+            })),
             Rope(Node::Branch(b)) => {
                 let mut s = Rope::new(&[]);
                 let mut start = start;