if (defined($value_type) and length($value_type) and ($value_type eq 'ARRAY'
 or ((ref($value) !~ /^(CODE)|(HASH)|(SCALAR)$/) and $value->isa('ARRAY')))) {
      (ref($param_map->{$param}) eq 'HTML::Template::LOOP') or
        croak("HTML::Template::param() : attempt to set parameter '$param' with 
an array ref - parameter is not a TMPL_LOOP!");