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How to run

You need to have boot installed. You also need to have the JVM installed. I have tested with version 8.

$ boot build will create a .jar file in the target/ directory.

Load the app into a repl

To start a repl with the app loaded, run boot repl. It also opens a nrepl, so you can connect another editor, such as Cursive or CIDER (you can also just M-x cider-jack-in, if you are a CIDER user)



Text in Rad is represented as a buffer. A buffer is a list of lines, and lines are string.

Here is an example of a rad buffer

["Rad is meant"
"to be hacked!"]

This will render into

Rad is meant
to be hacked!

Functions manipulating buffers are mostly in rad.buffer. Go hack there :).


It's really easy to make front-ends for rad. You can do it in 5 minutes, I'm sure.

Front-ends communicate with Rad thru channels, from clojure.core.async. If you are unfamiliar with core.async, do this repl-based core.async-tutorial.

A front-end is nothing more than a function returning a hash-map with 3 channels. Here is a (silent and useless) rad front-end:

(require '[clojure.core.async :as async)
(defn worthless-frontend
  {:print-chan (async/chan)
    :in-chan (async/chan)
    :point-chan (async/chan)})
  • Rad will send whatever text to print thru :print-chan.

  • The point (a vector of 2 numbers, describing [x y] of the cursor) is sent to :point-chan whenever it's updates, so you can put it in the right position in your front-end.

  • Send any keystrokes into :in-chan, preferably as char (like \d, \a, etc).


Rad (currently) has 2 modes. They are defined in rad.mode.

  • Insert mode
  • Command mode

Insert mode is like any text editor - type something, and it shows up on the screen.

Command mode is kind of like vim. I'll document this better later...


Rad packages are crazy simple. They have exactly the same form as a Clojure ns macro. Only difference is: a rad package requires a docstring and an attr-map.

Rad packages are a vector where the first element is a ns declaration. Think a normal clojure file, wrapped in [].

All packages in ~/.rad/packages will be loaded upon startup.

All standard packages that are distributed along with Rad are located in ../standard-packages/.

To load a package from file, use rad.package/load-package-from-file!.

To load a package from a Clojure list (beginning with the symbol ns), use rad.package/load-package!.

Example package - test-package

This is the package I used for testing. It's very small but shows off what capabilities lie in Rad packages.

(ns replace-buffer-with-happy-message
  "Replaces the current buffers content with an uplifting message.
  Just for fun."
  {:author {:name "Martin Josefsson"
            :url ""
            :email ""}
   :command-map '{\!
                       (fn [] (reset! rad.state/current-buffer

(println "Happy Hacking :)")
(defn message! []
  (let [msg "Happy Hacking :)"]
    (println (str "Happy Hacking :)" msg))

When replace-buffer-with-happy-message is loaded (with rad.package/load-package-from-file!), it will print "Happy Hacking :)" to STDOUT.

It also adds the command-mode command happy, which uses vars defined in rad.buffer as well as in the package.

Add the replace-buffer-with-happy-message package to ~/.rad/packages, restart Rad, enter command mode and type happy and you will see it in action.


A hackable enviroment

Bret Victor explains it: youtube link

Computer programs are not what you type into your source files.

We who create in the medium of the computer write code in a file. Then we feed it to a compiler. Then we run the program. Then we observe it.

This works, and you get a working program out in the end.

Like the painter instantly sees the result of their stroke on the canvas, and the musician instantly hears the sound of the plucked string. We, who create for the medium of the computer, also have that opportunity.

There is another way

Programs can be created interactively. With Rad I hope to shorten the path between thought and program execution.

Interactive development, for all languages

In Rad, the command e e stands for "Evaluate Expression", evaluating what is under the point.

con▮sole.log("Hello Rad!");

means point. The command e e here will evaluate the expression under the point. It will run the function console.log in a Javascript repl under the hood.

The same of course is even simpler for lisps.

(map ▮inc [1 2 3)

The e e command will here evaluate within the map, and you will see [2 3 4].

I've yet to figure out how to get this functionality in non-interpreted languages, but I'm sure it's doable.

Keyboard-driven design

Put your fingers on the home row. If you don't touch, type, learn it in 20 minutes.

You now have 47 inputs, at your fingertips (on my keyboard). Combine with modifier keys, and that number is multiplied.

When using a mouse, you have two possible inputs (right and left click).

Dissatisfaction with current programmers enviroments


  • Not easy to extend
  • Not a good enviroment to build apps
  • You have to remember what mode you are in


  • Gap buffers instead of line-based one (like rad, vim & atom) (This is the reason why showing line numbers is slow in Emacs)
  • Blocking all the time, nothing is async
  • Emacs pinky. Your pinky finger is always resting on Ctrl or Meta. That leaves a 10-fingered person with only 9 fingers available.
  • My coworkers hate pairing with me


  • You end up using the mouse a lot
  • Not a lisp (still an amazing editor though)
  • Slow as hell
  • JS has no core.async


All contributions given to this project, I (Martin Josefsson) own. By contributing, you agree to this.

All Rad source code is licensed under GPLv3. You can read the full text in Licence-gpl3.txt.

My hope is that Rad will be hacked upon, and I hope that this license can aid in that.

Your own code that interacts with Rad can have whatever license you wish to, of course.

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