How to get function's name as string in Clojure?

Question

How can you get function\'s name as string in Clojure?

What I have so far doesn\'t look anywhere near idiomatic:

(defn fn-name
  [f]
  (first (re-find #\         


        

Answer 1

I suggested an improvement to @carocad's answer in a comment. Since I also needed to do this, and I needed to do it in both clj and cljs, here is what I came up with:

(ns my-ns.core
  (:require [clojure.string :as s]
            #?(:clj [clojure.main :refer [demunge]])))

(defn fn-name
  [f]
  #?(:clj
      (as-> (str f) $
            (demunge $)
            (or (re-find #"(.+)--\d+@" $)
                (re-find #"(.+)@" $))
            (last $))
     :cljs
      (as-> (.-name f) $
            (demunge $)
            (s/split $ #"/")
            ((juxt butlast last) $)
            (update $ 0 #(s/join "." %))
            (s/join "/" $))))

Note that cljs.core has its own demunge built in and can't access clojure.main.

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Edit

Note that when you do (with-meta a-fn {...}), it returns a clojure.lang.AFunction in clojure, which hides the underlying name and namespace information. There may be other situations like that, I'm not sure. With fn literal forms, you can do ^{...} (fn ...) instead of (with-meta (fn ...) {...}) and it won't return a clojure.lang.AFunction, but that workaround won't work with predefined functions. I haven't tested any of this in clojurescript to see if it works the same way.

Note also that anonymous functions in clojure will always end in fn, as in "my-ns.core/fn". Normally these functions would have a "--[0-9]+" at the end, but the regex above removes that. You could modify the function above and make an exception for anonymous functions. As long as the lambda has an internal name, that will be used, e.g.:

(fn-name (fn abc [x] x)) ;;=> "my-ns.core/abc"

Again, I haven't tested any of these notes in clojurescript yet.