Idiomatically defining dynamic tasks in SBT 0.13?

Question

I\'m moving an SBT plugin from 0.12 over to 0.13. At various points in my plugin I schedule a dynamic set of tasks onto the SBT build graph.

Answer 1

You can use Def.taskDyn, which provides the new syntax for flatMap. The difference from Def.task is that the expected return type is a task Initialize[Task[T]] instead of just T. Translating your example,

inParallel := parTask.value

def parTask = Def.taskDyn {
   val t = times.value
   ordinals.value.map(o => ordinalTask(o, t)).joinWith(_.join)
}

def ordinalTask(o: String, t: Int) = Def.task {
   (0 until t).map(_ => o).mkString(",")
}