remove duplicate in undo/redo implementation

src/edit.rs

@@ -6,6 +6,50 @@ pub enum EditKind {
     Insert(String, usize),
 }
 
+impl EditKind {
+    fn redo(&self, row: usize, lines: &mut Vec<String>) {
+        match self {
+            EditKind::InsertChar(c, i) => {
+                lines[row].insert(*i, *c);
+            }
+            EditKind::DeleteChar(_, i) => {
+                lines[row].remove(*i);
+            }
+            EditKind::InsertNewline(i) => {
+                let line = &mut lines[row];
+                let next_line = line[*i..].to_string();
+                line.truncate(*i);
+                line.push(' ');
+                lines.insert(row + 1, next_line);
+            }
+            EditKind::DeleteNewline(_) => {
+                if row > 0 {
+                    let line = lines.remove(row);
+                    let prev_line = &mut lines[row - 1];
+                    prev_line.pop(); // Remove trailing space
+                    prev_line.push_str(&line);
+                }
+            }
+            EditKind::Insert(s, i) => {
+                lines[row].insert_str(*i, s.as_str());
+            }
+        }
+    }
+
+    fn undo(&self, row: usize, lines: &mut Vec<String>) {
+        use EditKind::*;
+        match self {
+            InsertChar(c, i) => DeleteChar(*c, *i).redo(row, lines),
+            DeleteChar(c, i) => InsertChar(*c, *i).redo(row, lines),
+            InsertNewline(i) => DeleteNewline(*i).redo(row, lines),
+            DeleteNewline(i) => InsertNewline(*i).redo(row, lines),
+            Insert(s, i) => {
+                lines[row].replace_range(*i..s.len(), "");
+            }
+        }
+    }
+}
+
 pub struct Edit {
     kind: EditKind,
     cursor_before: (usize, usize),
@@ -27,60 +71,12 @@ impl Edit {
 
     pub fn redo(&self, lines: &mut Vec<String>) {
         let (row, _) = self.cursor_before;
-        match self.kind {
-            EditKind::InsertChar(c, i) => {
-                lines[row].insert(i, c);
-            }
-            EditKind::DeleteChar(_, i) => {
-                lines[row].remove(i);
-            }
-            EditKind::InsertNewline(i) => {
-                let line = &mut lines[row];
-                let next_line = line[i..].to_string();
-                line.truncate(i);
-                line.push(' ');
-                lines.insert(row + 1, next_line);
-            }
-            EditKind::DeleteNewline(_) => {
-                if row > 0 {
-                    let line = lines.remove(row);
-                    let prev_line = &mut lines[row - 1];
-                    prev_line.pop(); // Remove trailing space
-                    prev_line.push_str(&line);
-                }
-            }
-            EditKind::Insert(ref s, i) => {
-                lines[row].insert_str(i, s.as_str());
-            }
-        }
+        self.kind.redo(row, lines)
     }
 
     pub fn undo(&self, lines: &mut Vec<String>) {
         let (row, _) = self.cursor_after;
-        match self.kind {
-            EditKind::InsertChar(_, i) => {
-                lines[row].remove(i);
-            }
-            EditKind::DeleteChar(c, i) => {
-                lines[row].insert(i, c);
-            }
-            EditKind::InsertNewline(_) => {
-                let line = lines.remove(row);
-                let prev_line = &mut lines[row - 1];
-                prev_line.pop(); // Remove trailing space
-                prev_line.push_str(&line);
-            }
-            EditKind::DeleteNewline(i) => {
-                let line = &mut lines[row];
-                let next_line = line[i..].to_string();
-                line.truncate(i);
-                line.push(' ');
-                lines.insert(row + 1, next_line);
-            }
-            EditKind::Insert(ref s, i) => {
-                lines[row].replace_range(i..s.len(), "");
-            }
-        }
+        self.kind.undo(row, lines)
     }
 
     pub fn cursor_before(&self) -> (usize, usize) {