module sieve is

!nat_sup 30

channel NAT_CHANNEL is 
   (N : NAT) 
end channel

process GENERATOR [RIGHT: NAT_CHANNEL] (in var CUR: NAT) is
   while CUR <= 31 loop
      RIGHT (CUR);
      CUR := CUR + 1
   end loop;
   stop
end process

process UNIT [LEFT, RIGHT, OUTPUT: NAT_CHANNEL] is
   var P, N: NAT in
      LEFT (?P) where P != 0;
      OUTPUT (P);
      loop
         LEFT (?N);
         if (N mod P) != 0 then
            RIGHT (N)
         end if
      end loop
   end var
end process

end module