Tweeking Emacs Modeline for Clojure Development

Emacs is fun to configure and if you have the basics of LISP or Clojure then its pretty easy too. After reading how to replace the text on the modeline I decided to customise my mode-line to make it more efficient for Clojure development. I’ll cover how I tweaked the mode line and added this customisation to my Emacs Live based configuration.

Instead of a long list of Major and Minor modes that are active, I now have symbols representing those modes.

In the screen-shot you can see I have the following modes running

λ Clojure mode
τ undo-tree
γ yas
υ volatile highlights
ηζ nREPL minor mode
α auto-complete
φ paredit

Some other modes are active, but hidden with a null string as I am assuing they are running all the time.

Configuring Emacs Live

Adding these to the Emacs Live configuration I use is easy, assuming you used the “bro-grammer” script provided by +Sam Aaron. This script creates a ~/.live-pack folder where you can add your own keybindings and configuration without it getting hit by Emacs Live updates.

I created a file called clean-mode-line.el, based on the one in the Mastering Emacs article. The file is located in my personal live-packs folder at:

~/.live-packs/jr0cket-pack/config/clean-mode-line.el

The code for the mode-line tweaks is a Github Gist:

To use this new mode-line tweak, we ask Emacs Live to load the configuration in clean-mode-lime.el. To do this, edit the init.el file in your live pack

~/.live-packs/jr0cket-pack/init.el 

Then add the following code:

Emacs Tweaked

When you open a Clojure document, the mode line now displays the major and minor modes as symbols.

Starting the Clojure REPL using M-x nrepl-jack-in gives you a similar modeline, this time with the major mode being nrepl-mode.

Switching back to a Clojure file after running nREPL shows Clojure as the major mode and nREPL running as the minor mode.

In Summary

The custom mode line was really easy to set up, thanks to the great info in the Matering Emacs article. The tricky part was finding the specific name for the nREPL minor mode that was running. Other than that it took a couple of minutes, most of which was deciding which symbols to use. I added a few others at the end of the file in case I change my mind or you want to use something more meaningful to yourself.

I havent tried this with Swank, but I assume that all it would take is adding of the swank mode to the clean-mode-line.el file.

When I get round to using other modes, I will see if I can add other symbols to my configuration where it makes sense. Let me know if you find this useful and what symbols you use.

Thank you.
@jr0cket

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