Make vars constant for use in case statements in Clojure -


in clojure, there way make var constant such can used in case statements?

e.g.

(def 1) (def b 2)  (let [x 1]   (case x     :1     b :2     :none)) => :none

i understand can use cond or condp around this, nice if define not require further evaluation use case.

related , answer stolen it:

as docstring tells you: no cannot this. can use chas emericks macro , however:

(defmacro case+   "same case, evaluates dispatch values, needed referring    class , def'ed constants java.util.enum instances."   [value & clauses]   (let [clauses (partition 2 2 nil clauses)         default (when (-> clauses last count (== 1))                   (last clauses))         clauses (if default (drop-last clauses) clauses)         eval-dispatch (fn [d]                         (if (list? d)                           (map eval d)                           (eval d)))]     `(case ~value        ~@(concat (->> clauses                    (map #(-> % first eval-dispatch (list (second %))))                    (mapcat identity))            default))))

thus:

(def ^:const 1) (def ^:const b 2) (let [x 1]   (case+ x     :1     b :2     :none)) => :1

an alternative (which nice since it's more powerful) use core.match's functionality. though can match against local bindings:

(let [x 2       a       b b]   (match x     :1     b :2     :none))  => :2

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