Using a Place or a Place-Channel as a sync event returns the value of a
place-channel-get and not the Place itself.
Most events return the actual `thing' which one sync'd on. This is not
true with places and channels, one gets the message itself.
The conundrum is identification of which Place / Place-Channel actually
fired. Places themselves have no real mechanism supporting GUID labeling
or even simple naming/labeling. There is no (place-name my-place) or
ability to assign an identifier upon creation. There is documented support
for Place and Place-Channel equality. So one can work around all this at
the app code level, i.e. implement their own labeling system for Places.
However assuming a roll your own labeling system there is still
the anonymity of a place / place-channel when used as a sync event issue.
(let ((msg (sync pl-1 pl-2 pl-3))))
;; no idea from which place msg came from, unless explicitly recorded in
the msg itself.
;; e.g. (Msg-sender msg) -> my home brewed Place-GUID
Compare and contrast with ports used as an event. A port used as a sync
event results in the port itself upon which one can do whatever this
knowledge. For example, I might opt *not* to read the port as this time,
even unilaterally close it without reading.
Consider the following parallel, asynchronous request/response idiom.
Given N request msgs and P places, issue one request message per ready
place. (Ready in the sense it is not processing a request.)
I want something like
(let loop ((msgs ...))
...
(let ((ready-place (sync p1 p2 p3)))
(process-response (place-channel-get ready-place))
(process-request ready-place (car msgs))
(loop (cdr msgs))
How would one approach something like this given `sync' not returning the
ready place but the received msg from some anonymous place which was ready.
Thanks,
Ray
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