I just noticed that the ReadableInstant[0] interface is generic, extending Comparable<T> [1]. Is it possible to implement a generic interface with a defrecord?
[0] http://joda-time.sourceforge.net/apidocs/org/joda/time/ReadableInstant.html [1] http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Comparable.html On Wednesday, September 10, 2014 4:15:51 PM UTC+1, j...@afandian.com wrote: > > Thanks. Sorry this is turning into a bit of a brain dump. I've created my > record that decorates the original type: > > (defprotocol IWeirdDate > (as-date [this]) > (pp [this])) > > (defrecord WeirdDate [year month day] > IWeirdDate > (pp [this] (condp = month > 21 (str "Spring " year) > 33 (str "Third Quarter of " year) > (str (as-date this)) > )) > > (as-date [this] > (let [[y m d] (condp = month > 21 [year 3 day] ; spring > 33 [year 7 1] ; third quarter > > ; ... others > > ; default > [year month day])] > (clj-time/date-time y m d))) > > clj-time/DateTimeProtocol > (clj-time/year [this] (clj-time/year (as-date this))) > (month [this] (clj-time/month (as-date this))) > (day [this] (clj-time/day (as-date this))) > (day-of-week [this] (clj-time/day-of-week (as-date this))) > (hour [this] (clj-time/hour (as-date this))) > (minute [this] (clj-time/minute (as-date this))) > (sec [this] (clj-time/sec (as-date this))) > (second [this] (clj-time/second (as-date this))) > (milli [this] (clj-time/milli (as-date this))) > (clj-time/after? [this that] (clj-time/after? (as-date this) that)) > (before? [this that] (clj-time/before? (as-date this) that))) > > And I want to be able to use some functions in both directions: > > (def x (WeirdDate. 1986 5 2)) > (def y (clj-time/date-time 2014 5 2)) > (prn (clj-time/before? x y)) > (prn (clj-time/after? y x)) > > The first one works, the second one fails with `ClassCastException: > WeirdDate cannot be cast to org.joda.time.ReadableInstant`. I think this is > because of a type hint which is present on the on the > org.joda.time.DateTime implementation[0] of the DateTimeProtocol but not on > the protocol: > > (after? [this ^ReadableInstant that] (.isAfter this that)) > > So I add the ReadableInstant methods to the WeirdDate record: > > ReadableInstant > (.equals [this readableInstant] (.equals (as-date this) > readableInstant)) > (.get [this type] (get (as-date this) type)) > (.getChronology [this] (.getChronology (as-date this))) > (.getMillis [this] (.getMillis (as-date this))) > (.getZone [this] (.getZone (as-date this))) > (.hashCode [this] (.hashCode (as-date this))) > (.isAfter [this instant] (.isAfter (as-date this) instant)) > (.isBefore [this instant] (.isBefore (as-date this) instant)) > (.isEqual [this instant] (.isEqual (as-date this) instant)) > (.isSupported [this field] (.isSupported (as-date this) field)) > (.toInstant [this] (.toInstant (as-date this))) > (.toString [this] (.toString (as-date this))) > > Now I get `IllegalArgumentException: Must hint overloaded method: get`. So > I annotate according to the Java interface[1]: > > ReadableInstant > (.equals ^boolean [this ^Object readableInstant] (.equals (as-date > this) readableInstant)) > (.get ^int [this ^DateTimeFieldType type] (get (as-date this) type)) > (.getChronology ^Chronology [this] (.getChronology (as-date this))) > (.getMillis ^long [this] (.getMillis (as-date this))) > (.getZone ^DateTimeZone [this] (.getZone (as-date this))) > (.hashCode ^int [this] (.hashCode (as-date this))) > (.isAfter ^boolean [this ^ReadableInstant instant] (.isAfter (as-date > this) instant)) > (.isBefore ^boolean [this ^ReadableInstant instant] (.isBefore > (as-date this) instant)) > (.isEqual ^boolean [this ^ReadableInstant instant] (.isEqual (as-date > this) instant)) > (.isSupported ^boolean [this ^DateTimeFieldType field] (.isSupported > (as-date this) field)) > (.toInstant ^Instant [this] (.toInstant (as-date this))) > (.toString ^String [this] (.toString (as-date this))) > > Again, `IllegalArgumentException: Must hint overloaded method: get`. > > As far as I know this is all correctly annotated, although I'm not sure > about the return types, as records aren't mentioned in the documentation[2] > but it does say "For function return values, the type hint can be placed > before the arguments vector". > > Any ideas? > > [0] > https://github.com/clj-time/clj-time/blob/v0.7.0/src/clj_time/core.clj#L126 > [1] > http://joda-time.sourceforge.net/apidocs/org/joda/time/ReadableInstant.html > [2] http://clojure.org/java_interop#Java Interop-Type Hints > -- You received this message because you are subscribed to the Google Groups "Clojure" group. 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