    /*
     *  call-seq:
     *     index_reader.term_count(field) -> int
     *
     *  Same return a count of the number of terms in the field
     */
    static VALUE
    frb_ir_term_count(VALUE self, VALUE rfield)
    {
        IndexReader *ir = (IndexReader *)DATA_PTR(self);
        TermEnum *te = ir_terms(ir, frb_field(rfield));
        int count = 0;
        while (te->next(te)) {
            count++;
        }
        te->close(te);
        return INT2FIX(count);
    }