How do I make sbt use the scala binaries from $SCALA_HOME directory?

Question

sbt downloads new version of scala compiler and the scala library for every sbt project at this location: ./project/boot/scala-2.8.1/lib/scala-library.jar
./project/boot/scala-2.8.1/lib/scala-compiler.jar

How do I make it pick up the compiler and the library from the location pointed by $SCALA_HOME?

Also, I am surprised that it's not a common requirement. Do Scala developers prefer to use a separate copies of compiler and library for every project?

I found the same request which was unanswered: http://groups.google.com/group/simple-build-tool/browse_thread/thread/9e2c7bc34253ad0f?pli=1

Thanks in advance for your help.

Answer 1

Disclaimer, I don't use this myself but I was curious about whether this is possible.

Based on using a local scala instance, I defined the following project:

import sbt._
import java.io.File

class Test(info: ProjectInfo) extends DefaultProject(info) {
  override def localScala = 
    defineScala("2.8.1-local", new File(System.getenv("SCALA_HOME"))) :: Nil
}

Then in project/build/build.properties:

build.scala.versions=2.8.1-local

Then I can see that the console target works fine, which would suggest that it would work for compilation and running as well.