package Before;
my %looper;
use overload
    '&{}' => sub {
        my ( $f ) = @_;
        my $fs = overload::StrVal($f);
        if( $looper{$fs} ){
            print "$fs   got looper already\n";
            return $looper{overload::StrVal($f)};
        } else {
            my $looper = 0;
            my $s = sub {
                $looper++;
                print "$fs  Stuff before (looper=$looper)\n";
                goto &$f unless $looper > 1;
            };
            $looper{$fs} = $s;
            return $s;
        }
    };

package main;
( bless sub {} => 'Before' )->()
__END__
Before=CODE(0x18305e4)  Stuff before (looper=1)
Before=CODE(0x18305e4)   got looper already
Before=CODE(0x18305e4)  Stuff before (looper=2)