new

special form

since v0.0-927

clojure.core/new

Edit

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Source docstring:

The args, if any, are evaluated from left to right, and
passed to the JavaScript constructor. The constructed object is
returned.

(defmethod parse 'new
  [_ env [_ ctor & args :as form] _ _]
  (disallowing-recur
   (let [enve (assoc env :context :expr)
         ctorexpr (analyze enve ctor)
         ctor-var (when (#{:var :local :js-var} (:op ctorexpr))
                    (resolve-existing-var env ctor))
         record-args
         (when (and (:record ctor-var) (not (-> ctor meta :internal-ctor)))
           (repeat 3 (analyze enve nil)))
         argexprs (into (vec (map #(analyze enve %) args)) record-args)
         known-num-fields (:num-fields ctor-var)
         argc (count args)]
     (when (and (not (-> ctor meta :internal-ctor))
                (some? known-num-fields)
                (not (or (= known-num-fields argc)
                         (and (:record ctor-var)
                              (= (+ 2 known-num-fields) argc)))))
       (warning :fn-arity env {:argc argc :ctor ctor}))
     {:env env :op :new :form form :class ctorexpr :args argexprs
      :children [:class :args]
      :tag (let [tag (-> ctorexpr :info :tag)]
             (if (and (js-tag? tag)
                      (not (prim-ctor? tag)))
               'js ; some foreign thing, drop the prefix
               (let [name (-> ctorexpr :info :name)]
                 (or (js-prim-ctor->tag name) name))))})))

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(defmethod emit* :new
  [{ctor :class :keys [args env]}]
  (emit-wrap env
             (emits "(new " ctor "("
                    (comma-sep args)
                    "))")))

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