syntax = "proto2"; package tutorial; message Person { optional string name = 1; optional int32 id = 2; optional string email = 3; enum PhoneType { PHONE_TYPE_UNSPECIFIED = 0; PHONE_TYPE_MOBILE = 1; PHONE_TYPE_HOME = 2; PHONE_TYPE_WORK = 3; } message PhoneNumber { optional string number = 1; optional PhoneType type = 2 [default = PHONE_TYPE_HOME]; } repeated PhoneNumber phones = 4; } message AddressBook { repeated Person people = 1; }