/*
 *  call-seq:
 *     sort_field.reverse? -> bool
 *
 *  Return true if the field is to be reverse sorted. This attribute is set
 *  when you create the sort_field.
 */
static VALUE
frt_sf_is_reverse(VALUE self)
{
    GET_SF();
    return sf->reverse ? Qtrue : Qfalse;
}