JDK
JDK, the Java Development Kit, version 1.6 or 1.7
Sbt
Sbt, a build tool for Scala, version 0.12.0
macOS
Install it using Macports:
$ sudo port install sbt
Verify it works:
$ sbt -h
Getting org.scala-sbt sbt 0.13.0 ...
Scala IDE for Eclipse
The Scala IDE for Eclipse