ietf-openproxy
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Re: P: single assignment semantics

2003-10-28 21:59:15

Alex,

While I do strongly agree about the possibility of different values of
the same expression at different points in a P program (due to
adaptation and so on), this example of yours confused me...
Assume, for example, that name is a response
body-dependent expression and code A above executes a callout service
on the response headers. By the time the service call completes, the
processor may read a few more chunks of that response body and the
value of the named expression can change. A simpler example would be:

        current_time := Time.now();     // interpreted in the morning
        ...
        if (current_time.isEvening()) { // can this become true?
                ...
        }
How can the processor read a few more chunks while performing the rule
processing ? If this is so, then I suppose, we would end up in a non
deterministic behaviour!

In other words, my question is probably about the vectoring point.. what
are options for vectoring point for a non-HTTP protocol, for example?

Sorry - if this is already specified in a different draft, pl give me a
pointer to that...

regards
geetha