int_id<monfaction>::int_id( const string_id<monfaction> &id ) : _id( id.id() ) { }
int_id<ter_t>::int_id( const string_id<ter_t> &id ) : _id( id.id() ) { }
int_id<vpart_info>::int_id( const string_id<vpart_info> &id ) : _id( id.id() ) { }
int_id<furn_t>::int_id( const string_id<furn_t> &id ) : _id( id.id() ) { }
int_id<trap>::int_id( const string_id<trap> &id ) : _id( id.id() ) { }