Fun with data-orientation

[he_who_journals]

Define var so that all input to var is posted by var back to var's input. This operation is done independent of time; if a is posted to var, this operation will be repeated at every moment, and because it is repeated at every point in the interval between the time of posting and the time of polling (checking what value var is posting to itself), a will be the result of a poll.

What happens when b is also posted to var? This shouldn't be difficult and I don't think it is, but I'm having trouble deciding and proving my decision. Does b replace a as the polled value? Does a continue and b never shows up? Do both a and b come out in the polling? I am fairly sure that only the first or the third could be it -- but which?, and how does one prove it? Really, though, I think more axioms are needed.

Now, here's the thing. At the moment when b is posted to var from outside, a is being posted to var by var. If neither is defined as overriding the other (if an external post preempts the input stream and kills off the self-post) do we end up with a contradiction or simply with a paradox? Time isn't defined for var, only for var's self-posting; does var spin off into two alternate realities in which both a and b are being posted to var at every moment?

And I have now gotten very fast at typing the tag for italics.