me <- ['key -> "enro",
       'chan -> channel("enro")];

hist <- <>;

clients <- [ ];

func serve()
let( m = receive(me['chan]))
in 
   state do( if(p1(m) notin dom(clients) -> 
                        clients <- clients + [p1(m) ->channel(p1(m))]),
             hist <- <m:hist>)
   return let (r = eval(p2(m))) 
          in send(clients[p1(m)],r);

run()=while(do(serve(),true));