Hi Rich, I like the flexibility of the new watches, but I'm missing a way to watch for errors. Currently, if an agent's action results in an error its watchers aren't even triggered.
Thanks, Anand On Feb 27, 2:57 pm, Rich Hickey <richhic...@gmail.com> wrote: > I've added (back)synchronouswatches(svn 1309+), which used to exist > for agents, now for all reference types. > > (defn add-watch > > "Experimental. > > Adds a watch function to an agent/atom/var/ref reference. The watch > fn must be a fn of 4 args: a key, the reference, its old-state, its > new-state. Whenever the reference's state might have been changed, > any registeredwatcheswill have their functions called. The watch > fn > will be called synchronously, on the agent's thread if an agent, > before any pending sends if agent or ref. Note that an atom's or > ref's state may have changed again prior to the fn call, so use > old-state rather than derefing the reference. Note also that watch > fns > may be called from multiple threads simultaneously. Var watchers are > triggered only by root binding changes, not thread-local set!s" > > [reference key fn] ...) > > (defn remove-watch [reference key]...) > > I've left in add/remove-watcher for now, in order to avoid disruption. > It is defined in terms of add-watch, demonstrating add-watch is the > more flexible core function. My plan is to remove add-watcher/remove- > watcher, since you can build your own such variants. > > Highlights are: > > - Deterministic times when callbacks will occur. > > - Provision of before/after state - you determine what constitutes an > interesting change. > > - Arbitrary key will be passed back to callback. > > Please try them out for your latest Cells-like and other reactive > programs. I'd like to move this out of the experimental category. > > Feedback and questions welcome, > > Rich --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
