module LINK_4 (DATA) is

process LINK [INPUT, OUTPUT:PORT] is
   loop
      alt
         INPUT (TOKEN);
         OUTPUT (TOKEN)
      []
         INPUT (TOKEN)
      []
         var Ai:ADDR in
            INPUT (CLAIM, ?Ai);
            OUTPUT (CLAIM, Ai)
         end var
      end alt
   end loop
end process

end module