cider-diet

(because it is supposed to be lightweight)

Clojars: https://clojars.org/cider-diet

Why

See clojure-emacs/cider#1717

Timings:

command	time	description
java -jar Test	0.1s	JVM startup time is blazing fast. Simple Hello World app starts almost instantly:
java -jar clojure-1.8.0.jar	1-1.3s	Clojure REPL is much slower, but still pretty fast:
java -cp $MY_CIDER_NREPL_CP clojure.main	1-1.3s	Clojure REPL with cider-nrepl's CLASSPATH
lein repl (+ nrepl)	11s	Slow: Ten times slower!
lein repl (+ nrepl) + cider-nrepl	20-24s	SLOWER
cider-jack-in	30-32s	Unbearably SLOW

What

The idea is to get working nREPL session for cider fast.
I don't know why we need lein/boot/gradle for that.
For example, lein repl does a lot of stuff under the hood (not just java -jar clojure-1.X.Y.jar), that is why it takes so long to start.

In 99% of cases when I want to write Clojure code (not often these days) all I need is a working Clojure REPL + frontend (emacs) for it.
What I don't want in 100% of cases is to wait 30s before it starts.

So I decided to do this.

command	time	description
cider-diet-jack-in	4s	Much better!

How

1. Checkout this repo

2. lein uberjar (creates cider-diet-1.0.1-standalone.jar).

   java -jar cider-diet-1.0.1-standalone.jar [<port_number>] starts nREPL on port <port_number> (7888 by default).

3. Put that jar somewhere

4. Use the following function:

;; this is just an example, replace path with the correct one!
(setq cider-diet-path (expand-file-name (concat (getenv "HOME")
                                                "/git/cider-diet/target/cider-diet-1.0.1-standalone.jar")))

(defun cider-diet-jack-in ()
  (interactive)
  (let* ((cider-diet-process (start-process "cider-diet-nrepl" "*cider-diet-nrepl*" 
                                            "java" "-jar" cider-diet-path "7888"))) 
    (accept-process-output cider-diet-process)
    (cider-connect "localhost" 7888)))

Then just call cider-diet-jack-in to start nREPL AND make cider connect to it. OR Use cider-connect command if you already have cider-diet standalone process running (for example, if you started it manually via java -jar cider-diet-1.0.1-standalone.jar command).

There is also a Boot task created by @arichiardi:
https://gist.github.com/arichiardi/86ccc450e243e9964e723d73f2f1db2c

Results

For me it takes 4 seconds to have working cider connected to nREPL.
I'm not sure if all middleware works, but at least I have pretty-printed stacktraces and other stuff.

TODO

1. Check dependencies
2. Pass additional options and parameters

License

Copyright © 2016 kovrik

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.