private static List<Command> loadRewrites(String str){
  assert str != null;
  List<Command> commands=new ArrayList<>();
  for (  String line : str.split("\n")) {
    addLine(commands,line);
  }
  return commands;
}

private static List < Command > loadRewrites ( String str ) { assert str != null ; List < Command > commands = new ArrayList < > ( ) ; for ( String line : str . split ( "\n" ) ) { addLine ( commands , line ) ; } return commands ; }
loads the rewrites from tab - separated values .
