Thanks, that was very informative. I got no technical reason to expect that implementing an interface would define a function, lets just say that it felt right :/
2011/7/29 Aaron Cohen <aa...@assonance.org> > On Fri, Jul 29, 2011 at 3:18 PM, Andreas Liljeqvist <bon...@gmail.com>wrote: > >> Is this a bug? >> >> > Nope, expectation dissonance. > > >> (defprotocol Notcloseable (dosomething [this])) >> >> > This is what actually defines the function "dosomething". Once this > definition happens, the function exists and can be called. If you try to > call it before there are any implementations though you'll get: > > user=> (dosomething 1) > java.lang.IllegalArgumentException: No implementation of method: > :dosomething of protocol: #'user/Notcloseable found for class: > java.lang.Integer (NO_SOURCE_FILE:0) > > It _also_ for interop purposes defines a Java interface, which classes that > implement the protocol may or may not implement. If you use extend-type, > they will not. If you use deftype or defrecord to create a new class that > implements the protocol, it will also implement the interface. This is the > basis for the performance advantage of protocols. > > >> (defrecord Archive [] >> java.io.Closeable >> (close [_] (print "closeable")) >> >> Notcloseable >> (dosomething [_] (print "something"))) >> >> >> user> (def a (Archive.)) >> >> user> (.close a) >> closeable >> > > Uses interop to call through the Closeable interface. > > >> user> (close a) >> >> Unable to resolve symbol: close in this context >> [Thrown class java.lang.Exception] >> > > No such function exists. > > >> user> (dosomething a) >> something >> > > Uses the protocol function, and calls the implementation you've provided. > > >> user> (.dosomething a) >> something >> >> > Uses the interop support to call the Protocol's interface method. > > >> Implementing a protol creates both java function and a clojure function. >> Implementing an interface only creates the java function. >> > > I'm not sure why you expect that implementing an interface would create a > function? > > --Aaron > > -- > 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
