1 files changed, 72 insertions, 0 deletions
diff --git a/src/main/scala/forge/Target.scala b/src/main/scala/forge/Target.scala
new file mode 100644
index 00000000..80ff98c4
--- /dev/null
+++ b/src/main/scala/forge/Target.scala
@@ -0,0 +1,72 @@
+package forge
+
+import java.nio.{file => jnio}
+
+trait Target[T]{
+  val defCtx: DefCtx
+
+  val inputs: Seq[Target[_]]
+  def evaluate(args: Args): T
+
+  def map[V](f: T => V)(implicit defCtx: DefCtx) = {
+    Target.Mapped(this, f, defCtx)
+  }
+  def zip[V](other: Target[V])(implicit defCtx: DefCtx) = {
+    Target.Zipped(this, other, defCtx)
+  }
+  def ~[V, R](other: Target[V])
+             (implicit s: Implicits.Sequencer[T, V, R], defCtx: DefCtx): Target[R] = {
+    this.zip(other).map(s.apply _ tupled)
+  }
+
+}
+
+object Target{
+  def noop(inputs: Target[_]*)(implicit defCtx: DefCtx) = NoopTarget(inputs, defCtx)
+  case class NoopTarget(inputs: Seq[Target[_]], defCtx: DefCtx) extends Target[Unit]{
+    def evaluate(args: Args) = ()
+  }
+  def traverse[T](source: Seq[Target[T]])(implicit defCtx: DefCtx) = {
+    Traverse[T](source, defCtx)
+  }
+  case class Traverse[T](inputs: Seq[Target[T]], defCtx: DefCtx) 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,
+                          defCtx: DefCtx) 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],
+                          defCtx: DefCtx) extends Target[(T, V)]{
+    def evaluate(args: Args) = (args(0), args(0))
+    val inputs = List(source1, source1)
+  }
+
+  def path(path: jnio.Path)(implicit defCtx: DefCtx) = Path(path, defCtx)
+  case class Path(path: jnio.Path, defCtx: DefCtx) extends Target[jnio.Path]{
+    def evaluate(args: Args) = path
+    val inputs = Nil
+  }
+  case class Subprocess(inputs: Seq[Target[_]],
+                        command: Args => Seq[String],
+                        defCtx: DefCtx) extends Target[Subprocess.Result] {
+
+    def evaluate(args: Args) = {
+      jnio.Files.createDirectories(args.dest)
+      import ammonite.ops._
+      implicit val path = ammonite.ops.Path(args.dest, pwd)
+      val output = %%(command(args))
+      assert(output.exitCode == 0)
+      Subprocess.Result(output, args.dest)
+    }
+  }
+  object Subprocess{
+    case class Result(result: ammonite.ops.CommandResult, dest: jnio.Path)
+  }
+}