Add :kind command to REPL

:kind command diplays the kind of types and type constructors in Scala
syntax notation.

    scala> :kind (Int, Int) => Int
    scala.Function2's kind is F[-A1,-A2,+A3]

2 files changed, 44 insertions, 0 deletions

diff --git a/test/files/run/kind-repl-command.check b/test/files/run/kind-repl-command.check
new file mode 100644
index 0000000000..afa32acdae
--- /dev/null
+++ b/test/files/run/kind-repl-command.check
@@ -0,0 +1,32 @@
+Type in expressions to have them evaluated.
+Type :help for more information.
+
+scala> 
+
+scala> :kind scala.Option
+scala.Option's kind is F[+A]
+
+scala> :k (Int, Int) => Int
+scala.Function2's kind is F[-A1,-A2,+A3]
+
+scala> :k -v Either
+scala.util.Either's kind is F[+A1,+A2]
+* -(+)-> * -(+)-> *
+This is a type constructor: a 1st-order-kinded type.
+
+scala> :k -v scala.collection.generic.ImmutableSortedMapFactory
+scala.collection.generic.ImmutableSortedMapFactory's kind is X[CC[A,B] <: scala.collection.immutable.SortedMap[A,B] with scala.collection.SortedMapLike[A,B,CC[A,B]]]
+(* -> * -> *(scala.collection.immutable.SortedMap[A,B] with scala.collection.SortedMapLike[A,B,CC[A,B]])) -> *
+This is a type constructor that takes type constructor(s): a higher-kinded type.
+
+scala> :k new { def empty = false }
+AnyRef{def empty: Boolean}'s kind is A
+
+scala> :k Nonexisting
+<console>:8: error: not found: value Nonexisting
+              Nonexisting
+              ^
+
+scala> 
+
+scala> 
diff --git a/test/files/run/kind-repl-command.scala b/test/files/run/kind-repl-command.scala
new file mode 100644
index 0000000000..df1fafb667
--- /dev/null
+++ b/test/files/run/kind-repl-command.scala
@@ -0,0 +1,12 @@
+import scala.tools.partest.ReplTest
+
+object Test extends ReplTest {
+  def code = """
+  |:kind scala.Option
+  |:k (Int, Int) => Int
+  |:k -v Either
+  |:k -v scala.collection.generic.ImmutableSortedMapFactory
+  |:k new { def empty = false }
+  |:k Nonexisting
+  """.stripMargin
+}