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" ;  


##</code><code>##

ARG[123]
ARG[456]
foo1: RE[123]
foo2: RE[456]

##</code><code>##

  my $e = 10 ;
  my $sub = eval(" sub { return 2**$e } ") ;

##</code><code>##

  sub foo { print "foo\n" ;}
  # now redefining it:
  *foo = sub { print "bar\n" ;}