PPCODE:
    // the number of return value is known
    EXTEND(SP, things.size());
    // cycle a list of things
    for (size_t i=0; i<things.size(); i++)
    {
        AV* curr_slot = newAV();
        SV* sv_obj = newSV(NULL);
        sv_setref_pv(sv_obj, "My::Class", things[i].obj);
        SV* sv_num1 = newSViv(things[i].foo);
        SV* sv_num2 = newSViv(things[i].bar);
        SV* sv_num3 = newSViv(things[i].baz);
        av_push(curr_slot, sv_obj);
        av_push(curr_slot, sv_num1);
        av_push(curr_slot, sv_num2);
        av_push(curr_slot, sv_num3);
        mPUSHs((SV*) curr_slot);
    }