/*
 *  call-seq:
 *     term_doc_enum.doc -> doc_id
 *
 *  Returns the frequency of the current document pointed to by the
 *  +term_doc_enum+.
 */
static VALUE
frt_tde_freq(VALUE self)
{
    TermDocEnum *tde = (TermDocEnum *)DATA_PTR(self);
    return INT2FIX(tde->freq(tde));
}