sub param
{
  my $self=shift;
  my $name=shift;

  if(@_)
  {
    my $val=shift;
    my $method="set_$name";
    #croak("use method $method(<value>)") if($self->can($method));
    $self->$method($val) if($self->can($method));
    return 0 unless(exists($self->{$name}));
    $self->{$name}=$val;
    return 1;
  }

  my $method="get_$name";
  #croak("use method $method(<value>)") if($self->can($method));
  $self->$method() if($self->can($method));
  return undef unless(exists($self->{$name}));
  return $self->{$name};
}