I think you want handle-evt, eg: (sync (handle-evt p1 (lambda (x) (list p1 x))) ....)
Robby On Thu, Dec 13, 2012 at 4:27 PM, Ray Racine <ray.rac...@gmail.com> wrote: > 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 > > > > > > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users > >
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