ZTable*         O_OBJECT
TriangleMesh*         O_OBJECT
Point*         O_OBJECT
Line*           O_OBJECT
Polyline*       O_OBJECT
PolylineCollection*    O_OBJECT
Polygon*        O_OBJECT
ExPolygon*      O_OBJECT
ExPolygonCollection*    O_OBJECT
ExtrusionEntityCollection*    O_OBJECT
ExtrusionPath*  O_OBJECT
ExtrusionLoop*  O_OBJECT
Surface*        O_OBJECT
SurfaceCollection*      O_OBJECT

ExtrusionRole     T_UV
SurfaceType     T_UV
ClipperLib::JoinType		T_UV
ClipperLib::PolyFillType		T_UV

# we return these types whenever we want the items to be cloned
Points          T_ARRAYREF
Lines           T_ARRAYREF
Polygons        T_ARRAYREF
ExPolygons      T_ARRAYREF

# we return these types whenever we want the items to be returned
# by reference and marked ::Ref because they're contained in another
# Perl object
Polygons*       T_ARRAYREF_PTR

# we return these types whenever we want the items to be returned
# by reference and not marked ::Ref because they're newly allocated
# and not referenced by any Perl object
TriangleMeshPtrs T_PTR_ARRAYREF

INPUT

T_ARRAYREF
    if (SvROK($arg) && SvTYPE(SvRV($arg)) == SVt_PVAV) {
        AV* av = (AV*)SvRV($arg);
        const unsigned int len = av_len(av)+1;
        $type* tmp = new $type(len);
        for (unsigned int i = 0; i < len; i++) {
            SV** elem = av_fetch(av, i, 0);
            (*tmp)[i].from_SV_check(*elem);
        }
        $var = *tmp;
	    delete tmp;
    } else
        Perl_croak(aTHX_ \"%s: %s is not an array reference\",
	             ${$ALIAS?\q[GvNAME(CvGV(cv))]:\qq[\"$pname\"]},
	             \"$var\");

OUTPUT

T_ARRAYREF
	AV* av = newAV();
	$arg = newRV_noinc((SV*)av);
	sv_2mortal($arg);
	av_extend(av, $var.size()-1);
	int i = 0;
    for (${type}::const_iterator it = $var.begin(); it != $var.end(); ++it) {
        av_store(av, i++, it->to_SV_clone_ref());
	}
	$var.clear();

T_ARRAYREF_PTR
    AV* av = newAV();
	$arg = newRV_noinc((SV*)av);
	sv_2mortal($arg);
	av_extend(av, $var->size()-1);
	int i = 0;
    for (${ my $t = $type; $t =~ s/\*$//; \$t }::iterator it = $var->begin(); it != $var->end(); ++it) {
        av_store(av, i++, it->to_SV_ref());
	}

T_PTR_ARRAYREF
    AV* av = newAV();
	$arg = newRV_noinc((SV*)av);
	sv_2mortal($arg);
	av_extend(av, $var.size()-1);
	int i = 0;
    for (${type}::iterator it = $var.begin(); it != $var.end(); ++it) {
        av_store(av, i++, (*it)->to_SV());
	}