Hi, I'm developing visualization component for some application. There is a protocol to be extended to existing application problem domain classes to specify how to visualize each type. The user can load predefined implementations of the protocol or create custom visualizations in REPL.
The problem is that now I need several independent instances of the visualizer (the kind of expandability almost free with well-designed OO systems) running simultaneously in the context of the same application each using different implementations of the protocol. I found that protocol is associated with a Var and extending the protocol changes the root binding of that Var (not documented?). It appears that protocol is not just a set of definitions but adds state (current set of extenders and corresponding implementations) and extend function does not modify the protocol structure itself nor does it return new version of it but changes the state elsewhere. This makes dynamic use of protocols (e.g. having functions that create, accept or return protocols) problematic. Also it may be useful to have with-protocol macro that will bind function vars to the implementations associated with the specified instance of the protocol. -- 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 Note that posts from new members are moderated - please be patient with your first post. 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
