-- do nothing
  elseif key == 'lshift' or key == 'rshift' then

    lines[#lines] = lines[#lines]..' aaa'

    if key == 'r' then
      lines[#lines+1] = eval(lines[#lines])[1]
      lines[#lines+1] = ''
    end

function eval(buf)
  local f = load('return '..buf, 'REPL')
  if f then
    return call_gather(f)
  end
  local f, err = load(buf, 'REPL')
  if f then
    return call_gather(f)
  else
    return {err}
  end
end
-- based on https://github.com/hoelzro/lua-repl
function call_gather(f)
  local success, results = gather_results(xpcall(f, function(...) return debug.traceback() end))
  return results
end
function gather_results(success, ...)
  local n = select('#', ...)
  return success, { n = n, ... }
end