perl 에서 핸들러전달

자답이네요...

{
  package Test;

  sub new
  {
    my $class = shift;
    my $self = {};
    $self->{target} = undef;
    bless($self, $class);
    return $self;
  }

  sub prn
  {
    my $self = shift;
    if ($#_ == 2) {
      $self->{target} = shift;
    } else {
      $self->{target} = *STDOUT; // use the typeglob notation
    }
    $self->output(shift);
  }
   
  sub output
  {
    my $self = shift;
    my $content = shift;
    my $target = $self->{target}; // 변수로 한번 받아서..
    print($target <<END_TAG); 
starting print.
$content
end print.
END_TAG
  }   
 
}

$test = Test->new();
$test->prn("This is standard output test\n");
local *FILEHANDLE;
open(FILEHANDLE, ">", "prn.txt");
$test->prn(*FILEHANDLE, "This is file handle test\n"); // use the typeglob notation
close(FILEHANDLE);