ligo/test/contracts/max_in_list.tz

parameter (list int32);
storage unit;
return (option int32);
code {CAR; DIP{NONE int32};
      LAMBDA
        (pair int32 (option int32))
        (option int32)
        {DUP; DUP; CAR; SWAP; CDR;
         IF_NONE {DIP{DROP}; SOME} {CMPGT; IF {CDR} {CAR; SOME}}};
      REDUCE; UNIT; SWAP; PAIR};