Pathname#split

static VALUE
path_split(VALUE self)
{
    VALUE str = get_strpath(self);
    VALUE ary, dirname, basename;
    ary = rb_funcall(rb_cFile, id_split, 1, str);
    Check_Type(ary, T_ARRAY);
    dirname = rb_ary_entry(ary, 0);
    basename = rb_ary_entry(ary, 1);
    dirname = rb_class_new_instance(1, &dirname, rb_obj_class(self));
    basename = rb_class_new_instance(1, &basename, rb_obj_class(self));
    return rb_ary_new3(2, dirname, basename);
}