Conditional scalacOptions with SBT

Question

I am using a project with cross-build for Scala 2.8, 2.9 and (hopefully) 2.10, using SBT. I would like to add the -feature option when compiling with 2.10 only.

Answer 1

I found this was quick and concise way of doing it:

scalaVersion := "2.10.0"

crossScalaVersions := "2.9.2" :: "2.10.0" :: Nil

scalacOptions <<= scalaVersion map { v: String =>
  val default = "-deprecation" :: "-unchecked" :: Nil
  if (v.startsWith("2.9.")) default else default :+ "-feature"            
}