Thanks for your response Devin. I guess I had come to the same conclusion by the end of my email. But I wonder if there is a more direct way of achieving the same thing without using a macro that spits out a defrecord with in-line method declarations? I had a quick look at the defrecord code and didn't follow well enough to see what machinery is being used internally to extend the record to the java interface.
In short: why can I implement java interfaces within a defrecord body but not when using extend? Cheers, David On 9 July 2011 02:35, Devin Walters <dev...@gmail.com> wrote: > What I think Kevin meant to say was that you might consider using a macro. > > If you have questions about specifics, please do reply. This group is here to > Help, and it would be a shame if a response like the previous one steered you > away from asking a follow-up. > > Sent via mobile > > On Jul 8, 2011, at 5:14 PM, Kevin Downey <redc...@gmail.com> wrote: > >> if only lisp had macros >> >> On Fri, Jul 8, 2011 at 12:16 PM, David Jagoe <davidja...@gmail.com> wrote: >>> Hi All, >>> >>> I am battling with how to deal with the difference between Protocols >>> and Interfaces in a particular case. >>> >>> Consider the following code: >>> >>> (defrecord DomainTypeA [] >>> SomeInternalProtocol >>> (foo [this] "foo result") >>> >>> clojure.lang.IFn >>> (invoke [this] "invoke result")) >>> >>> This code works fine. >>> >>> However, I have a number of domain types all of which must use the >>> same implementation of foo and invoke. >>> >>> In the case off foo its easy: >>> >>> (defrecord DomainTypeA []) >>> (extend DomainTypeA SomeInternalProtocol >>> internal-protocol-implementation-map) >>> >>> However I cannot do: >>> >>> (extend DomainTypeA clojure.lang.IFn some-implementation) >>> >>> because IFn is a java Interface. How would I get arount this? >>> >>> My use case is as follows: >>> >>> Every one of my domain objects needs to implement invoke in the same >>> way, so I don't want to code it in-line on the record definition each >>> time. The implementation is defined in one place and I eventually want >>> a macro (e.g. defdomainobj but with a better name!) that would >>> automatically hook up the IFn def. >>> >>> Hmm maybe I just answered my own question: >>> >>> Should I just write the macro that spits out the code in my first listing? >>> >>> Thanks! >>> >>> Cheers, >>> David >>> >>> -- >>> 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 >> >> >> >> -- >> And what is good, Phaedrus, >> And what is not good— >> Need we ask anyone to tell us these things? >> >> -- >> 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 > > -- > 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 -- 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
