anchor.diff: -rem=rem --[[
  +rem=rem --[[--lua
   @setlocal&  set luafile="%~f0" & if exist "%~f0.bat" set luafile="%~f0.bat"
   @win32\lua5.1\bin\lua5.1.exe %luafile% %*&  exit /b ]]
   
  
positive.code:   vars.CONFBACKUPDIR = temppath
    mkdir(vars.CONFBACKUPDIR)
    exec(S[[COPY "$PREFIX\config*.*" "$CONFBACKUPDIR" >NUL]])
    exec(S[[COPY "$PREFIX\lua\luarocks\core\site_config*.*" "$CONFBACKUPDIR" >NUL]])
  end
  
  -- restore previously backed up config files
  local function restore_config_files()
    if not vars.CONFBACKUPDIR then return end -- there is no backup to restore
    exec(S[[COPY "$CONFBACKUPDIR\config*.*" "$PREFIX" >NUL]])
    exec(S[[COPY "$CONFBACKUPDIR\site_config*.*" "$PREFIX\lua\luarocks\core" >NUL]])
    -- cleanup
    exec(S[[RD /S /Q "$CONFBACKUPDIR"]])
    vars.CONFBACKUPDIR = nil
  
negative.code: 	return false
  end
  
  -- backup config[x.x].lua[.bak]
  local function backup_config_files()
    local temppath
    while not temppath do
  