Make the enter key work

src/editor.rs

@@ -123,6 +123,11 @@ impl Editor {
     // ------------------------------------------------------------------------
 
     fn read_key(&mut self) -> Option<EditorKey<char>> {
+        /*
+            TODO: Read 1 byte by default, and read additional bytes
+            if the first byte is an escape character, to resolve the
+            unintentional input throttling
+        */
         let stdin = io::stdin();
         let stdin = stdin.lock();
         let mut in_str = String::new();
@@ -294,9 +299,7 @@ impl Editor {
             match char {
                 Backspace => self._del_or_backspace(Backspace),
                 DeleteKey => self._del_or_backspace(DeleteKey),
-                Enter => {
-                    // TODO
-                }
+                Enter => self.insert_new_line(),
                 Escape => (),
                 ArrowUp => self.move_cursor(&ArrowUp),
                 ArrowDown => self.move_cursor(&ArrowDown),
@@ -585,9 +588,25 @@ impl Editor {
         row.render = str;
     }
 
-    fn append_row(&mut self, row: &str) {
-        self.rows.push(EditorRow::new(row));
-        self.update_row(self.rows.len() - 1);
+    fn insert_row(&mut self, at: usize, row: &str) {
+        if at > self.rows.len() {
+            return;
+        }
+
+        let row = EditorRow::new(row);
+        self.rows.insert(at, row);
+
+        self.update_row(at);
+
+        self.dirty += 1;
+    }
+
+    fn delete_row(&mut self, row_index: usize) {
+        if row_index > self.rows.len() {
+            return;
+        }
+
+        self.rows.remove(row_index);
 
         self.dirty += 1;
     }
@@ -607,6 +626,15 @@ impl Editor {
         self.dirty += 1;
     }
 
+    fn row_append_string(&mut self, row_index: usize, strng: &str) {
+        let row = &mut self.rows[row_index];
+        row.chars += strng;
+
+        self.update_row(row_index);
+
+        self.dirty += 1;
+    }
+
     fn row_delete_char(&mut self, row_index: usize, char_index: usize) {
         let row = &mut self.rows[row_index];
         if char_index >= row.chars.len() {
@@ -625,21 +653,55 @@ impl Editor {
 
     fn insert_char(&mut self, ch: char) {
         if self.cursor_y == self.rows.len() {
-            self.append_row("");
+            self.insert_row(self.rows.len(), "");
         }
 
         self.row_insert_char(self.cursor_y, self.cursor_x, ch);
         self.cursor_x += 1;
     }
 
+    fn insert_new_line(&mut self) {
+        if self.cursor_x == 0 {
+            self.insert_row(self.cursor_y, "");
+        } else {
+            let row = &mut self.rows[self.cursor_y];
+            let row_chars = row.chars.clone();
+            let len = row.chars.len() - self.cursor_x;
+
+            // Truncate the old row if you aren't at the end of a line
+            if self.cursor_x < row.chars.len() {
+                row.chars.truncate(self.cursor_x);
+            }
+
+            let slice = &row_chars[self.cursor_x..];
+            self.insert_row(self.cursor_y + 1, slice);
+
+            self.update_row(self.cursor_y);
+        }
+
+        self.cursor_y += 1;
+        self.cursor_x = 0;
+    }
+
     fn delete_char(&mut self) {
         if self.cursor_y == self.rows.len() {
             return;
         }
 
+        if self.cursor_x == 0 && self.cursor_y == 0 {
+            return;
+        }
+
         if self.cursor_x > 0 {
             self.row_delete_char(self.cursor_y, self.cursor_x - 1);
             self.cursor_x -= 1;
+        } else {
+            // When deleting the first character in the row, collapse that row into the previous one
+            self.cursor_x = self.rows[self.cursor_y - 1].chars.len();
+            self.row_append_string(self.cursor_y - 1, &self.rows[self.cursor_y].chars.clone());
+            self.delete_row(self.cursor_y);
+
+            self.cursor_y -= 1;
         }
     }
 
@@ -669,7 +731,7 @@ impl Editor {
         let lines = buf_reader.lines().map(|l| l.unwrap());
 
         for line in lines {
-            self.append_row(&line);
+            self.insert_row(self.rows.len(), &line);
         }
 
         self.dirty = 0;