RetroLogger - Bringing old school log level commands to sbt-0.10.x

RetroLogger.scala

// 
// RetroLogger
// A handy sbt-0.10.x plugin that allows you to set the log level like in the old days (aka sbt-0.7.x)
// "set logLevel := Level.Debug"  ====> "debug"
//
// + put this file in ~/.sbt/plugins/
// + add "sbtPlugin := true" to ~/.sbt/plugins/build.sbt

import sbt._
import Keys._

object RetroLogger extends Plugin {

  private def log(level: String) = (state: State) =>
    BuiltinCommands.addAlias(state, level, "set logLevel := Level.%s%s" format (level.head.toUpper, level.tail))

  // The workaround from above.
  override lazy val settings: Seq[Setting[_]] = Seq[Setting[_]](
    onLoad in Global <<= (onLoad in Global) ?? identity[State],
    onLoad in Global ~= { oldState =>
      log("error") compose log("warn") compose log("info") compose log("debug") compose oldState
    })
}