runMany: repeat runMain task in SBT

build.sbt

lazy val runMany = inputKey[Unit]("Run a main class X times.")

// > runMany 8 my.Benchmark args ...
runMany in Compile := {

  import complete.DefaultParsers._

  val x = token(Space ~> IntBasic, "times to run").parsed

  val runAgain = (runMain in Compile).parsed

  for {
    i <- 1 to x
  } yield {
    runAgain.value
  }
}

last.log

build.sbt:15: error: Illegal dynamic reference: runAgain
    runAgain.value
    ^

Main.scala

package proj

object Main extends App