int compare_string(Char const *begin,Right const &r)
 {
     Char const *end = begin;
     while(*end!=0)
         end++;
     return compare_text(begin,end,r.begin(),r.end());
 }
 int compare_text(Left const &l,Right const &r)
 {
     return compare_text(l.begin(),l.end(),r.begin(),r.end());
 }