Is there an online tool to auto-indent and format Clojure code like there are many for JSON?

Question

There are a lot of tools online that take a JSON text and show you formatted and well indented format of the same.

Some go even further and make a nice tree-like structu

Answer 1

Have a look at https://github.com/xsc/rewrite-clj It is brand new and does exactly what you are asking for.

EDIT I am still getting upvotes for this. I believe I found a better solution: You can easily do this with clojure.pprint utilizing code-dispatch without using an external library.

(clojure.pprint/write '(defn prime? [n known](loop [cnt (dec (count known)) acc []](if (< cnt 0) (not (any? acc))                                                                                                 (recur (dec cnt) (concat acc [(zero? (mod n (nth known cnt)))]))))) 
  :dispatch clojure.pprint/code-dispatch)
=> 
(defn prime? [n known]
  (loop [cnt (dec (count known)) acc []]
    (if (< cnt 0)
      (not (any? acc))
      (recur
        (dec cnt)
        (concat acc [(zero? (mod n (nth known cnt)))])))))

Answer 2

I'm not aware of any online services which do this, but there are Clojure libraries which serve this purpose. clojure.pprint comes with Clojure (the key function is clojure.pprint/pprint); Brandon Bloom's fipp is a significantly faster alternative.

Note that neither of these is particularly likely to format code as a programmer armed with Emacs would; they're close enough to be useful, however, and for literal data (not intended to be interpreted as code) may well match human standards.

Answer 3

There is now https://github.com/weavejester/cljfmt for that purpose

Instructions

Add it in your Leiningen plugins:

:plugins [[lein-cljfmt "0.6.1"]]

Then, to autoformat all code in your project:

lein cljfmt fix

Sample

Your sample code will become:

(defn prime? [n known] (loop [cnt (dec (count known)) acc []] (if (< cnt 0) (not (any? acc))
                                                                  (recur (dec cnt) (concat acc [(zero? (mod n (nth known cnt)))])))))

After adding some linebreaks and reformatting again:

(defn prime? [n known]
  (loop [cnt (dec (count known)) acc []]
    (if (< cnt 0) (not (any? acc))
        (recur (dec cnt) (concat acc [(zero? (mod n (nth known cnt)))])))))

Answer 4

Following up on this - there is now http://pretty-print.net which will serve this very purpose for EDN and Clojure Code.