package ARRAY;
                                                                                                                                                            
  sub grep    { [eval "grep  {$_[1]}  \@{\$_[0]}"] }
  sub map     { [eval "map   {$_[1]}  \@{\$_[0]}"] }
  sub sort    { [eval "sort  {$_[1]}  \@{\$_[0]}"] }
                                                                                                                                                            
  # reverse is not used in this example
  sub reverse { [reverse @{$_[0]} ] }
  1;