occam-pi - occam-pi：扩展集合

Question

如果有人可以向我解释扩展会合的概念，我将不胜感激。谢谢。

Answer 1

扩展集合点允许您在接收到通道通信之后但在让其他进程继续之前执行操作。

PROC a(CHAN INT sendtoB, sendtoC):
  SEQ
    -- do some stuff
    ...
    -- communicate with B, this will not complete 
    -- until the extended rendezvous completes
    sendtoB ! 123
    -- do some other stuff before sending info to another process
    ...
    sendtoC ! 345
:

PROC b(CHAN INT receivefromA):
  INT tmp:
  SEQ
    --do some stuff
    receivefromA ?? tmp
      -- do some stuff before process C gets data from process a
      ...
    -- release the channel and do some other stuff
    ...
:    

PROC c(CHAN INT receivefromA):
  INT tmp:
  SEQ
    -- This will wait until proc b releases
    receivefromA ? tmp
    -- this will only run after the first communication from A to B completes.

PROC run(CHAN BYTE kyb, scr, err):
  CHAN INT AtoB, AtoC:
  PAR
    a(AtoB, AtoC)
    b(AtoB)
    c(AtoC)
: