-- Incredibly inefficient; we make a copy of lines on every single keystroke.
-- The hope here is that we're either editing small files or just reading large files.

-- makes a copy of lines on every single keystroke; will be inefficient with really long lines.

* Undo/redo may be sluggish in large files. Large files may grow sluggish in
  other ways. lines.love works well in all circumstances with files under
  50KB.

* If you kill the process, say by force-quitting because things things get
  sluggish, you can lose data.