has '_print' => (
    is      => 'ro',
    default => sub { Slic3r::Print->new },
    handles => [qw(apply_config extruders          expanded_output_filepath                     total_used_filament total_extruded_volume
                    placeholder_parser process)],
);

##</code><code>##

sub new {
    # TODO: port PlaceholderParser methods to C++, then its own constructor
    # can call them and no need for this new() method at all
    my ($class) = @_;
    my $self = $class->_new;
    $self->placeholder_parser->apply_env_variables;
    $self->placeholder_parser->update_timestamp;
    return $self;
}