[e-lang] [RFP] cross-language object serialization (E <---> Squeak-E)

Mark S. Miller markm at caplet.com
Tue Jan 21 08:11:07 UTC 2003

At 10:56 PM 1/20/2003 Monday, Robert Withers wrote:
>oops, I think that I do want this negotiation in VatTP.  In CapTP, neither 
>side knows who the incoming connection was, do they?

Don't need to. Since (by assumption in the previous reply), we're 
negotiating a semantics-free choice, we can treat each direction as a 
separate decision. I imagine a protocol like the following:

Both Alice and Bob just start speaking in Doc/XML. This lets message traffic 
flow prior to negotiating another format, which is good, since latency is 
more important that bandwidth or marshalling time.

Alice, whenever she feels like it, tells Bob "you also may speak to me in 
Doc/doc-code or Doc/term-tree". Alice says this on the Alice->Bob link, but 
she's speaking only about the Bob->Alice link.

Bob, anytime after he's gotten such permission, says in Doc/XML "I'm 
switching to Doc/doc-code". The next Bob->Alice packet must then be encoded 
in Doc/doc-code.

The above sequence of events may happen to be interleaved with a 
corresponding negotiation about the other direction, or not. In any case, 
these two choices don't need to be synchronized or coordinated.

So I think this issue should stay at the CapTP level.

Text by me above is hereby placed in the public domain


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