function is_absolute_path(path)
  local os_path_separator = package.config:sub(1,1)
  if os_path_separator == '/' then
    -- POSIX systems permit backslashes in filenames
    return path:sub(1,1) == '/'
  elseif os_path_separator == '\\' then
    local f = path:sub(1,1)
    return f == '/' or f == '\\'
  else
    error('What OS is this? LÖVE reports that the path separator is "'..os_path_separator..'"')
  end
end
function is_relative_path(path)
  return not is_absolute_path(path)
end

  if is_relative_path(filename) then
    filename = love.filesystem.getWorkingDirectory()..'/'..filename  -- '/' should work even on Windows
  end
--?   print('saving source settings', Settings.source.x, Settings.source.y, Settings.source.displayindex)
  return {
    x=Settings.source.x, y=Settings.source.y, displayindex=Settings.source.displayindex,
    width=App.screen.width, height=App.screen.height,
    font_height=Editor_state.font_height,
    filename=filename,
    screen_top=Editor_state.screen_top1, cursor=Editor_state.cursor1,
    show_log_browser_side=Show_log_browser_side,
    focus=Focus,
  }
end
function source.mouse_pressed(x,y, mouse_button)
  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
--?   print('mouse click', x, y)
--?   print(Editor_state.left, Editor_state.right)
--?   print(Log_browser_state.left, Log_browser_state.right)

  if is_relative_path(filename) then
    filename = love.filesystem.getWorkingDirectory()..'/'..filename  -- '/' should work even on Windows
  end
  return {

  local os_path_separator = package.config:sub(1,1)
  if filename:sub(1,1) ~= os_path_separator then
    filename = love.filesystem.getWorkingDirectory()..os_path_separator..filename

  if is_relative_path(filename) then
    filename = love.filesystem.getWorkingDirectory()..'/'..filename  -- '/' should work even on Windows