Configuring Eclipse scala project with SBT

Recently we started a new project here in Elo7 and this is a quick guide to help you to configure a new Scala project using SBT to manage your project dependencies and Eclipse as your IDE.

So... what is SBT?

"sbt is a build tool for Scala and Java projects that aims to do the basics well&" from scala-sbt.org

It manages your dependencies (using Apache Ivy) and supports mixed projects with Scala and Java.

Installing SBT

If you have homebrew in your mac

$ brew install sbt

If you are using another platforms refer to this site

Create a simple project

Create a new folder for your project

$ mkdir hello_scala

go to your new project folder and create a build.sbt file

$ cd hello_scala
$ vim build.sbt

This file describe your project and your dependencies, write the following to your file

name := "hello_scala"
version := "1.0"
scalaVersion := "2.10.2"

libraryDependencies ++= Seq(
  "org.specs2" %% "specs2" % "2.1.1" % "test",
  "junit" % "junit" % "4.11" % "test"
)

resolvers ++= Seq(
  "snapshots" at "http://oss.sonatype.org/content/repositories/snapshots",
  "releases" at "http://oss.sonatype.org/content/repositories/releases"
)

Here we are adding two dependencies to write unit tests, junit and specs2, and two extra resolvers for your dependencies. This is needed since SBT by default only have the Maven default repository in its list.

After this you will need to add a SBT Eclipse plugin.

$ mkdir project
$ echo "addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "2.2.0")" >> plugins.sbt

go to your project root directory and

$ sbt eclipse

This will download all your dependencies, create your eclipse project files and add your dependencies to project library.

In your eclipse!

Import your project and you are ready to go!

The project generated with sbt adds several source files directories, separating java source files from scala source files and tests from main code.

Saying Hello to the World!

object Hi {
  def main(args: Array[String]) = println("Hello World!")
}

go to your console and in your project root directory type:

$ sbt run

Thank you

Diego Kurisaki and David Robert