I've added (back) synchronous watches (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 registered watches will 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 -~----------~----~----~----~------~----~------~--~---
