Thanks, This works, but there's a problem: the labeledtextfield is not a textfield anymore, it's a label. Therefore it does not behave like a textfield (which implements other protocols as well). I need multiple inheritance, in one way or another. I've been trying to find a way to implement with multimethods.
For example, if label was a mixin, then it means I could do something like this: (def textfield (new TextField "Foo") (def labeledtextfield (new (mix TextField Label) "Name" "Foo")) (render textfield) ;=> [Foo] (render labeledtextfield) ;=> Name: [Foo] Oh, and I'd like to stay away from macros, if possible. :) Razvan On Feb 6, 12:20 pm, Matthias Diehn Ingesman <matdi...@gmail.com> wrote: > It sounds a little like the decorator pattern would do the trick for > you in this case - am I missing something? In case I am not, I have > given it a shot using records and protocols: > > (defrecord TextField [text]) > (defrecord DatetimePicker [datetimes]) > (defrecord Label [text widget]) > > (defprotocol Renderable > (render [this])) > > (extend-protocol Renderable > TextField > (render [this] > (str "[" (:text this) "]")) > > DatetimePicker > (render [this] > (apply str (:datetimes this))) > > Label > (render [this] > (str (:text this) ": " (render (:widget this))))) > > (comment > (def textfield (TextField. "Foo")) > (def datetimepicker (DatetimePicker. [:yesterday :today :tomorrow])) > (def labeledtextfield (Label. "Name" textfield)) > (def labeleddatetimepicker (Label. "Date" datetimepicker)) > (render textfield) ;=> [Foo] > (render datetimepicker) ;=> :yesterday:today:tomorrow > (render labeledtextfield) ;=> Name: [Foo] > (render labeleddatetimepicker) ;=> Date: :yesterday:today:tomorrow > ) > > 1/ is handled by the Renderable implementation for Label calling the > Renderable implementation on whatever widget it decorates with a > label. > > 2/ is handled by having the Label decorator widget as a record. > > Regards, > Matthias -- 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
