Do you know of a reason why (deftype [foo & more]) isn't read in as having two fields where the second is a seq?
Barring that, would it be reasonable to disallow & as a valid field name, thus preventing this class of error? On Nov 4, 11:54 pm, Christophe Grand <christo...@cgrand.net> wrote: > On Fri, Nov 5, 2010 at 1:39 AM, Mike Meyer < > > > > > > > > > > mwm-keyword-googlegroups.620...@mired.org> wrote: > > It seems like the polymorphism of protocols breaks inside the > > methods. This is a problem for having a function that's polymorphic > > between an object and a container of the same objects. > > > For instance: > > > user=> (defprotocol Tune (tweek [this])) > > Tune > > user=> (deftype Knob [name] Tune (tweek [this] (println "Tweeked" name))) > > user.Knob > > user=> (def base (Knob. "base")) > > #'user/base > > user=> (tweek base) > > Tweeked base > > nil > > user=> (def treble (Knob. "treble")) > > #'user/treble > > user=> (tweek treble) > > Tweeked treble > > nil > > user=> (deftype Box [& knobs] Tune (tweek [this] (for [knob knobs] (tweek > > knob)))) > > this vector is not an argument list but a field list, so you are defiing to > fields, one named & and one named knobs. > Try to evaluate (.name (.knobs (Box. base treble))) and you'll see that > knobs only holds treble. > > if you fix it: > (deftype Box [knobs] Tune (tweek [this] (for [knob knobs] (tweek knob)))) > > then: > (tweek (Box. [base treble])) > > will work as expected. > > If you really want var-args, you just have to write a factory fn > (defn box [& knobs] (Box. knobs)) > > hth, > > Christophe -- 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
