Added uniqueness annotations. Review by rytz.

4 files changed, 85 insertions, 0 deletions

diff --git a/src/library/scala/annotation/unique/package.scala b/src/library/scala/annotation/unique/package.scala
new file mode 100644
index 0000000000..a57a2bdfda
--- /dev/null
+++ b/src/library/scala/annotation/unique/package.scala
@@ -0,0 +1,31 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2002-2010, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.annotation
+
+/**
+ * An object that provides methods for capturing unique references, and
+ * for accessing unique fields.
+ *
+ * @author Philipp Haller
+ * @since 2.9
+ */
+package object unique {
+
+  trait Captured[A] {
+    def captured: A
+    def capturedBy[B](other: B): A = captured
+  }
+
+  implicit def mkCaptured[A](x: A) = new Captured[A] {
+    def captured: A = x
+  }
+
+  def swap[A, B <: A](to: A, from: B): A = to
+
+}
diff --git a/src/library/scala/annotation/unique/peer.scala b/src/library/scala/annotation/unique/peer.scala
new file mode 100644
index 0000000000..9159fd318c
--- /dev/null
+++ b/src/library/scala/annotation/unique/peer.scala
@@ -0,0 +1,18 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2002-2010, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.annotation.unique
+
+/**
+ * An annotation that indicates that the annotated parameter is in the
+ * same region as the parameter that is the argument of the annotation.
+ *
+ * @author Philipp Haller
+ * @since 2.9
+ */
+final class peer(x: AnyRef) extends annotation.StaticAnnotation
diff --git a/src/library/scala/annotation/unique/transient.scala b/src/library/scala/annotation/unique/transient.scala
new file mode 100644
index 0000000000..95f30758bb
--- /dev/null
+++ b/src/library/scala/annotation/unique/transient.scala
@@ -0,0 +1,19 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2002-2010, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.annotation.unique
+
+/**
+ * An annotation that indicates that the annotated parameter is transient.
+ * A transient parameter is borrowed in the sense that it is unique but it
+ * cannot be consumed.
+ *
+ * @author Philipp Haller
+ * @since 2.9
+ */
+final class transient extends annotation.StaticAnnotation
diff --git a/src/library/scala/annotation/unique/unique.scala b/src/library/scala/annotation/unique/unique.scala
new file mode 100644
index 0000000000..d2bf88a908
--- /dev/null
+++ b/src/library/scala/annotation/unique/unique.scala
@@ -0,0 +1,17 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2002-2010, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala.annotation.unique
+
+/**
+ * An annotation that indicates that the annotated parameter or field is unique.
+ *
+ * @author Philipp Haller
+ * @since 2.9
+ */
+final class unique extends annotation.StaticAnnotation