/*
 *  call-seq:
 *     filter.to_s -> string
 *
 *  Return a human readable string representing the Filter object that the
 *  method was called on.
 */
static VALUE
frt_f_to_s(VALUE self)
{
    VALUE rstr;
    char *str;
    GET_F();
    str = f->to_s(f);
    rstr = rb_str_new2(str);
    free(str);
    return rstr;
}