On Sun, Apr 11, 2010 at 06:39, Sophie <itsme...@hotmail.com> wrote: > (deftype A [x]) gives me an accessor (:x anA) > > Then I decide to change data representation of A without impacting > client code, but I don't seem able to define a function > (defn :x [anA] ...) > > Should I be doing something different?
It's not deftype that's giving you that accessor. All keywords, when used as a function of an map try to look themselves up in said map. (:somefield somemap) ;; means the same as: (somemap :somefield) ;; provided somemap isn't nil The things deftype defines behave like maps, which is why (:x anA) works the way you expect. You could defined accessor functions yourself and then use only those to access the internals of your A instances. You'd then only have to change the accessor function if the representation of A changed. (deftype may also provide better ways of accomplishing this, I haven't yet used it in practice.) (defn x-of-A [anA] (:x anA)) // Ben -- 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 To unsubscribe, reply using "remove me" as the subject.
