ScalahostPlugin.scala

import sbt._
import Keys._
import sbt.plugins.JvmPlugin

object ScalahostPlugin extends AutoPlugin {
  override def requires = JvmPlugin
  override def trigger: PluginTrigger = AllRequirements
  val metaVersion = "1.6.0-652.1486671053000"
  val pluginJar = sys.props.get("scalahost.pluginjar")

  override def projectSettings = Seq(
    commands += Command.command("dumpdb") { s =>
      val commands =
        Project
          .extract(s)
          .currentProject
          .aggregate
          .map(x => s"${x.project}/test:compile")
      println(
        s"Running commands in ${}:\n" + commands.mkString("- ", "\n- ", ""))
      "test:compile" :: s
    },
    resolvers += Resolver.bintrayIvyRepo("scalameta", "maven"),
    publishMavenStyle := false, // needed for intransitive()
    scalacOptions ++= {
      if (scalaVersion.value.startsWith("2.10")) Nil
      else {
        pluginJar.map(x => s"Xplugin:$x").toList ++
          List(
            "-Yrangepos",
            "-Xplugin-require:scalahost"
          )
      }
    },
    libraryDependencies ++= {
      if (scalaVersion.value.startsWith("2.10")) Nil
      else if (pluginJar.isDefined) Nil
      else
        compilerPlugin(
          ("org.scalameta" %% "scalahost" % metaVersion)
            .intransitive() // avoid redundant downloads
            .cross(CrossVersion.full)) ::
          Nil
    }
  )
}