A keyboard chording application: supercharge your typing by pressing more than one key at once.
Clojure Java C Other
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A pluggable framework for intercepting the key events that occur at a hardware level and doing "things" in response. "Things" can include running programs, altering the keystrokes to other keystrokes or combinations of keystrokes, or anything you can write code to do. There will be built-in support for doing things like moving the mouse from the keys on your keyboard.

The name "khordr" comes from the fact that the primary use case that motivated me to write this is to use key "chords" to accomplish things. A chord, like on a piano keyboard, is when more than one key is pressed simultaneously.


I've always been interested in typing. As a computer programmer, it's the primary mechanism I use to do my job. I've been very lucky not to experience any problems with RSI, but I nonetheless was intrigued by the unusual Kinesis keyboard, which some of my collegues at Relevance use.

I spent an entire month using the Kinesis. At the end of it, I decided that it wasn't for me, since I found it somewhat less comfortable and definitely slower than my crappy $12 keyboard. There was one thing I really liked about it, though, and that was the placement of the modifier keys: shift, control, and alt. As an emacs user, I frequently type all sorts of weird combinations of keys, and on the Kinesis these are generally much easier to do due to the fact that you can use your thumbs for something other than hitting the spacebar. As a result, typing things like control-alt-x are two thumbs and a finger.

Of course, I wanted the best of both worlds. I wanted my regular, non-weird keyboard, but I wanted to be able to type weird combinations of keys comfortably. If I could somehow physically move the shift, control, and alt keys to the middle of the keyboard, I'd be there.

What I realized is that this is, in fact, possible. One can use, for example, j for shift, k for control, and l for alt. The tricky part is in disambiguating situations where the user wants to simply type these keys from situations where the user wants to use them to modify other keys. There are several complications in doing this that I won't bore you with, but after months of working on it, I finally figured it out.

The cool thing is that along the way I wrote something far more general than something that only lets you use extra modifier keys. What I have in khordr is a generalized framework for reacting to key events at a very low level. This can be used to achieve all sorts of neat effects, like operating the mouse using your keyboard. That remains to be implemented, but the supporting code is there and should make the task relatively straightfoward.


khordr currently works only under Windows. I have plans to make it work for Mac OS X and ideally Linux.

You'll need to install the Interception device driver and reboot before using this application. NOTE! Having Interception on your system is technically a security risk, as it allows programs to intercept everything you type, including passwords. Note that this is a problem with installing any device driver, not just Interception.

The project is written in Clojure using Leinginen. Because the project also contains raw Java compiled by lein's javac task, you will need to correctly configure your setup for this. I'm not 100% sure what the magic here is, but I've gotten it to work by putting the following in my ~/.bashrc under Cygwin:

export LEIN_JAVA_CMD=~/bin/jdk/bin/java

where ~/bin/jdk is a symlink to /cygdrive/c/Program Files (x86)/Java/jdk1.7.0_07/. Yes, this is sort of awful. Sorry for that

Required Hardware

khordr should work with any keyboard, with one caveat: if you make use of a handler that relies on more than two keys being down simultaneously, you will probably need a decent keyboard. The feature you're looking for is called N-Key Rollover, or NKRO. It is common in gaming keyboards. Less capable keyboards often refuse to report additional keys once more than two are down, although they are fairly irregular about it. You may find, for example, that your keyboard is happy to report n, p, and j down, but won't report n, p, and q.


Huge thanks to Francisco Silva for writing Interception, without which I'd still be crashing my computer trying to write the device driver part of this myself.