Les 2 codes suivants sont strictement equivalents en termes de side-effects

explicit.clj

(ns lein-script-test
  (:require [ccw.util.eclipse :as e]
            [ccw.util.e4.model :refer (merge! app]))

(defn greet [context] (e/info-dialog "Hello world" "This popup provided to you from a user script"))

(merge! @app
  {:commands [{:element-id   "lein-script-test/greeter"
               :command-name "Hello from CCW"}]
   :handlers [{:command          "lein-script-test/greeter"
               :contribution-URI "bundleclass://ccw.core/clojure/ccw.util.e4.model/handler-factory/lein-script-test/greet"}]}))

implicit.clj

(ns lein-script-test
  (:require [ccw.util.eclipse :as e]
            [ccw.util.e4.model.dsl :refer-all]))

(defn greet [context] (e/info-dialog "Hello world" "This popup provided to you from a user script"))

(deffragment
  (defcommand greeter "Hello from CCW")
  (defhandler greeter greet))