initialize_copy

/* :nodoc: */
static VALUE
rb_reg_init_copy(copy, re)
    VALUE copy, re;
{
    if (copy == re) return copy;
    rb_check_frozen(copy);
    /* need better argument type check */
    if (!rb_obj_is_instance_of(re, rb_obj_class(copy))) {
        rb_raise(rb_eTypeError, "wrong argument type");
    }
    rb_reg_check(re);
    rb_reg_initialize(copy, RREGEXP(re)->str, RREGEXP(re)->len,
                      rb_reg_options(re));
    return copy;
}