sub foo {
  my ( $arg ) = @_ ;
  
  my $bar = sub {
    print "ARG[$arg]\n" ;
    return "RE[$arg]" ;
  } ;
  
  return $bar ;
}

  my $bar1 = foo(123) ;
  my $bar2 = foo(456) ;
  
  my $foo1 = &$bar1() ;
  my $foo2 = &$bar2() ;
  
  print "foo1: $foo1\n" ;
  print "foo2: $foo2\n" ;