Some good examples from everyone. Thank you. 2009/6/3 Richard Newman <holyg...@gmail.com>
> > Some work in which I'm currently engaged uses ad hoc hierarchies for > dispatching on a handler and either a message method or a method and > response code. In the realm of HTTP clients -- imagine that the > response arrives as a method invocation -- the equivalent would be > writing something like > > (defmethod do-response [MyHandler :post :ok] > ;; Handle a success response to my POST request > ) > > (defmethod do-response [MyHandler :any-method :failure] > ;; Handle any kind of failure response to any method (GET, POST, > PUT...). > ) > > The dispatch function can introspect the message itself to extract the > method, code, etc. etc. -- this is basically polymorphism over any > facet of the arguments, with full programmatic power to extract those > facets. Most importantly, applications can themselves augment the > hierarchy to include meaningful groupings -- in my example above, the > various methods all derive from :any-method, and you could easily > imagine a server having a :methods-i-cant-handle node in its > hierarchy, making that piece of logic explicit in the tree. > > This example doesn't look that compelling, except that my real domain > has a rich hierarchy of message and response types, which allows a > great deal of abstraction in message handling. > > (I hope one day to be able to unveil what I'm doing. It's not that > innovative, but it's not done yet!) > > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
