Primes

let rec
 from = lambda n. fromchan!n -> from (n+1),

 fromchan = chan,

 sieve = lambda inch.
   inch?p -> output!p {must be prime} ->
   let rec
     filter = inch?x ->
       if (x/p)*p<>x then {not p|x} connect!x -> filter
                     else filter,

     connect = chan

   in (filter || sieve connect)


in  from 2 || sieve fromchan

{\fB Parallel Sieve of Eratosthenese. \fP}