sbt/tasks/standard/Action.scala

50 lines
1.8 KiB
Scala

/* sbt -- Simple Build Tool
* Copyright 2010 Mark Harrah
*/
package sbt
import Types._
import Task._
// Action, Task, and Info are intentionally invariant in their type parameter.
// Various natural transformations used, such as PMap, require invariant type constructors for correctness
sealed trait Action[T]
final case class Pure[T](f: () => T) extends Action[T]
final case class Mapped[T, In <: HList](in: Tasks[In], f: Results[In] => T) extends Action[T]
final case class FlatMapped[T, In <: HList](in: Tasks[In], f: Results[In] => Task[T]) extends Action[T]
final case class DependsOn[T](in: Task[T], deps: Seq[Task[_]]) extends Action[T]
final case class Join[T, U](in: Seq[Task[U]], f: Seq[Result[U]] => Either[Task[T], T]) extends Action[T]
object Task
{
type Tasks[HL <: HList] = KList[Task, HL]
type Results[HL <: HList] = KList[Result, HL]
}
final case class Task[T](info: Info[T], work: Action[T])
{
def original = info.original getOrElse this
override def toString = info.name orElse original.info.name getOrElse ("Task(" + info + ")")
}
/** `original` is used during transformation only.*/
final case class Info[T](attributes: AttributeMap = AttributeMap.empty, original: Option[Task[T]] = None)
{
import Info._
def name = attributes.get(Name)
def description = attributes.get(Description)
def setName(n: String) = set(Name, n)
def setDescription(d: String) = set(Description, d)
def set[T](key: AttributeKey[T], value: T) = copy(attributes = this.attributes.put(key, value))
override def toString =
if(attributes.isEmpty && original.isEmpty)
"_"
else
attributes.toString + (original match { case Some(o) => ", original: " + o; case None => "" })
}
object Info
{
val Name = AttributeKey[String]("name")
val Description = AttributeKey[String]("description")
}