public MessageBox

[Nathan M. Swan]

On Wednesday, 21 March 2012 at 19:53:55 UTC, Sean Kelly wrote:
> On Mar 20, 2012, at 8:37 PM, Nathan M. Swan wrote:
>
>> After playing around with making a library with uses threads, 
>> I realized it would be nice if there could be multiple 
>> inter-thread mailboxes than just one per thread. That way, 
>> client code and third-party library code don't interfere with 
>> each other.
>
> They shouldn't interfere anyway.  The third-party code just has 
> to devise a message format that client code won't look for.  
> Though if the client discards messages arbitrarily via 
> receive((Variant v) {}) then all bets are off.

What about this pseudocode?

Thread1:
     spawn Thread2
     library sends LibMsg
     client sends ClientMsg

Thread2:
     client receives ClientMsg
     library receives LibMsg

The client will receiveOnly!ClientMsg() and get a MessageMismatch.

With multiple MessageBoxes:

Thread1:
     clientmail = new MessageBox
     spawn Thread2(libobj, clientmail)
     libobj.mb.send(LibMsg)
     cleintmail.send(ClientMsg)

Thread2:
     clientmail.receive(ClientMsg)
     libobj.mb.send(LibMsg)

If you scroll down to the section commented out as "doesn't 
work", it would work if my implementation could use MessageBoxes:

https://github.com/carlor/dcaflib/blob/master/buggy/asyncobj.d

As I posted a while back, the concept of a variant message queue 
is wonderful and powerful, and the implementation is great. But 
the fact that you can't declare "auto mq = new MessageQueue()" is 
a gaping whole in an otherwise A+ API.

(A+ as the grade, not the array programming language ;) )

NMS