1 files changed, 61 insertions, 0 deletions
diff --git a/src/main/scala/hbt/Target.scala b/src/main/scala/hbt/Target.scala
new file mode 100644
index 00000000..99f6e27d
--- /dev/null
+++ b/src/main/scala/hbt/Target.scala
@@ -0,0 +1,61 @@
+package hbt
+
+import java.nio.{file => jnio}
+
+import sourcecode.Enclosing
+
+trait Target[T]{
+  val label: String
+  val inputs: Seq[Target[_]]
+  def evaluate(args: Args): T
+
+  def map[V](f: T => V)(implicit path: Enclosing) = {
+    Target.Mapped(this, f, path.value)
+  }
+  def zip[V](other: Target[V])(implicit path: Enclosing) = {
+    Target.Zipped(this, other, path.value)
+  }
+  def ~[V, R](other: Target[V])
+             (implicit s: Implicits.Sequencer[T, V, R]): Target[R] = {
+    this.zip(other).map(s.apply _ tupled)
+  }
+
+}
+
+object Target{
+  def traverse[T](source: Seq[Target[T]])(implicit path: Enclosing) = {
+    Traverse[T](source, path.value)
+  }
+  case class Traverse[T](inputs: Seq[Target[T]], label: String) extends Target[Seq[T]]{
+    def evaluate(args: Args) = {
+      for (i <- 0 until args.length)
+      yield args(i).asInstanceOf[T]
+    }
+
+  }
+  case class Mapped[T, V](source: Target[T], f: T => V,
+                          label: String) extends Target[V]{
+    def evaluate(args: Args) = f(args(0))
+    val inputs = List(source)
+  }
+  case class Zipped[T, V](source1: Target[T],
+                          source2: Target[V],
+                          label: String) extends Target[(T, V)]{
+    def evaluate(args: Args) = (args(0), args(0))
+    val inputs = List(source1, source1)
+  }
+
+  def path(path: jnio.Path)(implicit label: Enclosing) = Path(path, label.value)
+  case class Path(path: jnio.Path, label: String) extends Target[jnio.Path]{
+    def evaluate(args: Args) = path
+    val inputs = Nil
+  }
+//  case class Command(inputs: Seq[Target[jnio.Path]],
+//                     output: Seq[Target[jnio.Path]],
+//                     label: String) extends Target[Command.Result]
+//  object Command{
+//    case class Result(stdout: String,
+//                      stderr: String,
+//                      writtenFiles: Seq[jnio.Path])
+//  }
+}