end
function dirname(path)
  local os_path_separator = package.config:sub(1,1)
  if os_path_separator == '/' then
    -- POSIX systems permit backslashes in filenames
    return path:match('.*/') or './'
  elseif os_path_separator == '\\' then
    return path:match('.*[/\\]') or './'
  else
    error('What OS is this? LÖVE reports that the path separator is "'..os_path_separator..'"')
  end
end
function test_dirname()
  check_eq(dirname('a/b'), 'a/', 'F - test_dirname')
  check_eq(dirname('x'), './', 'F - test_dirname/current')
end
function basename(path)
  local os_path_separator = package.config:sub(1,1)
  if os_path_separator == '/' then
    -- POSIX systems permit backslashes in filenames
    return string.gsub(path, ".*/(.*)", "%1")
  elseif os_path_separator == '\\' then
    return string.gsub(path, ".*[/\\](.*)", "%1")
  else
    error('What OS is this? LÖVE reports that the path separator is "'..os_path_separator..'"')
  end

function empty(h)
  for _,_ in pairs(h) do
    return false
  end
  return true
end

  Editor_state.screen_top1 = File_navigation.cursors[Editor_state.filename].screen_top1
  Editor_state.cursor1 = File_navigation.cursors[Editor_state.filename].cursor1

  if File_navigation.cursors[Editor_state.filename] then
    Editor_state.screen_top1 = File_navigation.cursors[Editor_state.filename].screen_top1
    Editor_state.cursor1 = File_navigation.cursors[Editor_state.filename].cursor1
  else
    Editor_state.screen_top1 = {line=1, pos=1}
    Editor_state.cursor1 = {line=1, pos=1}
  end

  Editor_state.filename = basename(Editor_state.filename)  -- migrate settings that used full paths; we now support only relative paths within the app