So the Interface specification has to be available when the record is defined... that makes sense. Thanks Jonathan.
On 10 July 2011 14:28, Jonathan Fischer Friberg <odysso...@gmail.com> wrote: > I think the reason is that an interface means that the function must be > 'inside' the class. > I.e you can call (.method object). Since it isn't possible to extend a java > class in that way, it isn't possible to use extend. In a defrecord body > however, a new class is defined, which means that it's possible to define > functions 'inside' that class. > > Protocols on the other hand doesn't define functions 'inside' the object, > they are simply standard functions. > > Jonathan > > On Sun, Jul 10, 2011 at 1:15 PM, David Jagoe <davidja...@gmail.com> wrote: >> >> 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 > > -- > 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. 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