CE edit handle backspace deletion into previous line

ce/edit.c

@@ -227,6 +227,24 @@ void edit_start (const char* file_path, const char* text) {
           gapbuffer_move (&editor.current_line->gb, editor.cursor.col);
           editor.cursor.col--;
           gapbuffer_backspace (&editor.current_line->gb);
+        } else {
+          if (editor.cursor.line > 0) {
+            struct list_node_link* prev = editor.current_line->lines_link.prev;
+            struct edit_line* prev_line = list_entry (prev, struct edit_line, lines_link);
+
+            size_t prev_len = gapbuffer_length (&prev_line->gb);
+
+            gapbuffer_concat (&wrealloc, NULL, &prev_line->gb, &editor.current_line->gb);
+
+            list_remove (editor.lines, &editor.current_line->lines_link);
+            free (editor.current_line->gb.buffer);
+            free (editor.current_line);
+            editor.current_line = prev_line;
+
+            editor.cursor.col = prev_len;
+            editor.cursor.line--;
+            editor.total_lines--;
+          }
         }
       }
       break;
@@ -272,16 +290,15 @@ void edit_start (const char* file_path, const char* text) {
     case KB_DELETE:
       if (editor.mode == EDIT_MODE_NORMAL) {
         size_t len = gapbuffer_length (&editor.current_line->gb);
-        gapbuffer_move (&editor.current_line->gb, editor.cursor.col);
 
         if (editor.cursor.col < len) {
+          gapbuffer_move (&editor.current_line->gb, editor.cursor.col);
           if (editor.current_line->gb.gap_end < editor.current_line->gb.size)
             editor.current_line->gb.gap_end++;
         } else {
           if (editor.cursor.line > 0) {
             struct list_node_link* next = editor.current_line->lines_link.next;
             struct edit_line* next_line = list_entry (next, struct edit_line, lines_link);
-            size_t next_len = gapbuffer_length (&next_line->gb);
 
             gapbuffer_concat (&wrealloc, NULL, &editor.current_line->gb, &next_line->gb);