/*
 *  call-seq:
 *     RangeFilter.new(field, options = {}) -> range_query
 *
 *  Create a new RangeFilter on field +field+. There are two ways to build a
 *  range filter. With the old-style options; +:lower+, +:upper+,
 *  +:include_lower+ and +:include_upper+ or the new style options; +:<+,
 *  +:<=+, +:>+ and +:>=+. The options' names should speak for themselves.
 *  In the old-style options, limits are inclusive by default.
 *
 *  == Examples
 *
 *    f = RangeFilter.new(:date, :lower => "200501", :include_lower => false)
 *    # is equivalent to 
 *    f = RangeFilter.new(:date, :< => "200501")
 *    # is equivalent to 
 *    f = RangeFilter.new(:date, :lower_exclusive => "200501")
 *
 *    f = RangeFilter.new(:date, :lower => "200501", :upper => 200502)
 *    # is equivalent to 
 *    f = RangeFilter.new(:date, :>= => "200501", :<= => 200502)
 */
static VALUE
frb_rf_init(VALUE self, VALUE rfield, VALUE roptions)
{
    Filter *f;
    char *lterm = NULL;
    char *uterm = NULL;
    bool include_lower = false;
    bool include_upper = false;
    
    get_range_params(roptions, &lterm, &uterm, &include_lower, &include_upper);
    f = rfilt_new(frb_field(rfield), lterm, uterm,
                  include_lower, include_upper);
    Frt_Wrap_Struct(self, NULL, &frb_f_free, f);
    object_add(f, self);
    return self;
}