my @parsed_data;
{
  open(my $fh, '<', $file) or die "Can't open $file ($!)\n";
  @parsed_data=parse($fh, fast => 1, lazy => 0);
  close($fh);
}

sub parse
{
  my $handle=shift(@_);
  my %options=@_;

  my @data;

  if($options{fast})
  {
    # ...
  }

  # parsen der Daten aus dem Filehandle $handle

  return @data;
}