/*
 *  call-seq:
 *     mod <=> other_mod   => -1, 0, +1, or nil
 *  
 *  Comparison---Returns -1 if <i>mod</i> includes <i>other_mod</i>, 0 if
 *  <i>mod</i> is the same as <i>other_mod</i>, and +1 if <i>mod</i> is
 *  included by <i>other_mod</i> or if <i>mod</i> has no relationship with
 *  <i>other_mod</i>. Returns <code>nil</code> if <i>other_mod</i> is
 *  not a module.
 */

static VALUE
rb_mod_cmp(mod, arg)
    VALUE mod, arg;
{
    VALUE cmp;

    if (mod == arg) return INT2FIX(0);
    switch (TYPE(arg)) {
      case T_MODULE:
      case T_CLASS:
        break;
      default:
        return Qnil;
    }

    cmp = rb_class_inherited_p(mod, arg);
    if (NIL_P(cmp)) return Qnil;
    if (cmp) {
        return INT2FIX(-1);
    }
    return INT2FIX(1);
}