sbt 0.11 run task examples needed - scala

Question

My projects are still using sbt 0.7.7 and I find it very convenient to have utility classes that I can run from the sbt prompt. I can also combine this with properties that are separately maintained - typically for environment related values that changes from hosts to hosts. This is an example of my project definition under the project/build directory:
class MyProject(info: ProjectInfo) extends DefaultProject(info) {
//...
lazy val extraProps = new BasicEnvironment {
// use the project's Logger for any properties-related logging
def log = MyProject.this.log
def envBackingPath = path("paths.properties")
// define some properties that will go in paths.properties
lazy val inputFile = property[String]
}
lazy val myTask = task { args =>
runTask(Some("foo.bar.MyTask"),
runClasspath, extraProps.inputFile.value :: args.toList).dependsOn(compile)
describedAs "my-task [options]"
}
}
I can then use my task as my-task option1 option2 under the sbt shell.
I've read the new sbt 0.11 documentation at https://github.com/harrah/xsbt/wiki including the sections on Tasks and TaskInputs and frankly I'm still struggling on how to accomplish what I did on 0.7.7.
It seems the extra properties could simply be replaced a separate environment.sbt, that tasks have to be defined in project/build.scala before being set in build.sbt. It also looks like there is completion support, which looks very interesting.
Beyond that I'm somewhat overwhelmed. How do I accomplish what I did with the new sbt?

Answer 1

You can define a task like this :
val myTask = InputKey[Unit]("my-task")
And your setting :
val inputFile = SettingKey[String]("input-file", "input file description")
You can also define a new configuration like :
lazy val ExtraProps = config("extra-props") extend(Compile)
add this config to your project and use it to set settings for this configuration :
lazy val root = Project("root", file(".")).config( ExtraProps ).settings(
inputFile in ExtraProps := ...
...
myTask in ExtraPops <<= inputTask { (argTask:TaskKey[Seq[String]]) =>
(argTask, inputFile) map { (args:Seq[String], iFile[String]) =>
...
}
}
).dependsOn(compile)
then launch your task with extra-props:my-task