ENSIME

the ENhanced Scala Interaction Mode for Emacs

Features

• Highlight errors and warnings in your code buffers.
• Inspect the type of any expression.
• Browse packages
• Completion-on-demand for variables, methods, constructors, etc.
• Jump to symbol definitions.
• Automated Refactorings (rename, organize imports, extract method...)
• Source Formatting
• Finds sbt,Maven,Ivy dependencies
• Scala REPL
• Scala Debugger
• Embedded sbt shell

Check out this (rather old)video or this one showcasing debugger support

System Requirements

• Emacs 22 or later.
• Unix-like OS or Windows. Note that you'll need to use bin/server.bat on windows.
• Java Runtime
• Scala 2.8 compatible source and libraries. ENSIME is built against the 2.8 nightly Scala releases.

Documentation

• The ENSIME User Manual

Quick Start

1) Install scala-mode

ENSIME is designed to compliment scala-mode (or any other scala language mode). scala-mode can be found in the Scala distribution under ./misc/scala-tool-support/emacs/. The rest of the steps assume your scala-mode is installed and working correctly.

2) Install ensime-mode

Download the ENSIME distribution from the github downloads page. Unpack the ENSIME distribution into a directory of your choosing.

Add the following lines to your .emacs file:

;; Load the ensime lisp code...
(add-to-list 'load-path "ENSIME_ROOT/elisp/")
(require 'ensime)

;; This step causes the ensime-mode to be started whenever
;; scala-mode is started for a buffer. You may have to customize this step
;; if you're not using the standard scala mode.
(add-hook 'scala-mode-hook 'ensime-scala-mode-hook)

;; MINI HOWTO: 
;; Open .scala file. M-x ensime (once per project)

3) Verify Permissions

Verify that the startup script (usually bin/server.sh) has executable permissions.

4) Create Project

In Emacs, execute M-x ensime-config-gen. Follow directions in the mini-buffer to create a .ensime file for your project..

5) Start ENSIME

Execute M-x ensime You only need to do this once per project.