i'm a clojure newbie and am pretty thoroughly confused by defprotocol, inline implementation and extend-type
i have the following two small files: crecords.tproc & crecrods.trec listed below: *A) crecords.tproc:* (ns crecords.tproc) (defprotocol Fruit (subtotal [this])) (defrecord Orange [qty]) (extend-type Orange Fruit (subtotal [this] (* 2 (:qty this)))) (defn -main [] ;; runs ok - note Absence of '.' before subtotal (println "Orange Subtotal:" (subtotal (Orange. 4)))) *B) crecords.trec:* (ns crecords.trec (:require [crecords.tproc :refer [Fruit]])) (defrecord Apple [qty] Fruit (subtotal [this] (* 5 (:qty this)))) (defrecord Banana [qty]) (extend-type Banana Fruit (subtotal [this] (* 3 (:qty this)))) (defn f1 [] ;; No matching field found: subtotal for class crecords.trec.Banana (println "Banana Subtotal:" (.subtotal (Banana 2)))) (defn f2 [] ;; Runs fine - Note the Presence of '.' before subtotal (println "Apple Subtotal:" (.subtotal (Apple. 8)))) (defn -main [] ; (f1) - Can't compile/run - see f1 comments (f2) ;; runs fine - see f2 comments ) When i run "lein run -m crecords.tproc", it produces the right answers. When i run "lein run -m crecords.trec", calling (f2) in main, it produces the right answers. When i run "lein run -m crecords.trec", calling (f1) in main, it crashes. Would seriously appreciate a good answer to the following: 1. Why *doesn't* extend-type (see Banana) work when implementing protocol Fruit in a different namespace 2. Why *does* inline implementation (see Apple) work when implementing protocol Fruit in a different namespace 3. Why the different function call "subtotal" (*without* Dot, see Apple) vs ".subtotal" (*with* Dot, see Orange) for extend-type vs inline implementation of Fruit? -- 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 unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
