/in/foo.cc:14:17: error: "<<" may not appear in macro parameter list
 #define left(now<<1)
                 ^~
/in/foo.cc:15:15: error: "(" may not appear in macro parameter list
 #define right((now<<1)+1)
               ^
/in/foo.cc:16:13: error: "(" may not appear in macro parameter list
 #define mid((l+r)>>1)
             ^