/in/foo.cc: In function 'bool comp(const Node&, const Node&)':
/in/foo.cc:39:18: warning: left operand of comma operator has no effect [-Wunused-value]
  else return !(A.code,A.len,B.code,B.len);
                ~~^~~~
/in/foo.cc:39:25: warning: right operand of comma operator has no effect [-Wunused-value]
  else return !(A.code,A.len,B.code,B.len);
                       ~~^~~
/in/foo.cc:39:31: warning: right operand of comma operator has no effect [-Wunused-value]
  else return !(A.code,A.len,B.code,B.len);
                             ~~^~~~