Merge pull request #739 from jsuereth/feature/collection-conversions

Adding copyInto and toVector methods to collections.

7 files changed, 52 insertions, 4 deletions

diff --git a/src/library/scala/collection/GenTraversableOnce.scala b/src/library/scala/collection/GenTraversableOnce.scala
index eadacd9209..e475865391 100644
--- a/src/library/scala/collection/GenTraversableOnce.scala
+++ b/src/library/scala/collection/GenTraversableOnce.scala
@@ -9,6 +9,8 @@
 package scala.collection
 
 import scala.reflect.ClassTag
+import scala.collection.generic.CanBuildFrom
+import scala.annotation.unchecked.{ uncheckedVariance => uV }
 
 /** A template trait for all traversable-once objects which may be
  *  traversed in parallel.
@@ -552,4 +554,21 @@ trait GenTraversableOnce[+A] extends Any {
    *               containing all key/value pairs of type `(T, U)` of this $coll.
    */
   def toMap[K, V](implicit ev: A <:< (K, V)): GenMap[K, V]
+
+  /** Converts this $coll to a Vector.
+   *  $willNotTerminateInf
+   *  @return a vector containing all elements of this $coll.
+   */
+  def toVector: Vector[A]
+
+  /** Converts this $coll into another by copying all elements.
+   *  @tparam Col  The collection type to build.
+   *  @return a new collection containing all elements of this $coll.
+   *  
+   *  @usecase def convertTo[Col[_]]: Col[A]
+   *    @inheritdoc
+   *    $willNotTerminateInf
+   *    @return a new collection containing all elements of this $coll.
+   */
+  def convertTo[Col[_]](implicit cbf: CanBuildFrom[Nothing, A, Col[A @uV]]): Col[A @uV]
 }
diff --git a/src/library/scala/collection/Iterator.scala b/src/library/scala/collection/Iterator.scala
index b2bbc8d888..5f369de3b7 100644
--- a/src/library/scala/collection/Iterator.scala
+++ b/src/library/scala/collection/Iterator.scala
@@ -11,6 +11,8 @@ package scala.collection
 import mutable.ArrayBuffer
 import annotation.migration
 import immutable.Stream
+import scala.collection.generic.CanBuildFrom
+import scala.annotation.unchecked.{ uncheckedVariance => uV }
 
 /** The `Iterator` object provides various functions for creating specialized iterators.
  *
@@ -1138,6 +1140,7 @@ trait Iterator[+A] extends TraversableOnce[A] {
   def toStream: Stream[A] =
     if (self.hasNext) Stream.cons(self.next, self.toStream)
     else Stream.empty[A]
+  
 
   /** Converts this iterator to a string.
    *
diff --git a/src/library/scala/collection/TraversableLike.scala b/src/library/scala/collection/TraversableLike.scala
index 3716a318d9..e5861f5760 100644
--- a/src/library/scala/collection/TraversableLike.scala
+++ b/src/library/scala/collection/TraversableLike.scala
@@ -616,6 +616,13 @@ trait TraversableLike[+A, +Repr] extends Any
   def toTraversable: Traversable[A] = thisCollection
   def toIterator: Iterator[A] = toStream.iterator
   def toStream: Stream[A] = toBuffer.toStream
+  // Override to provide size hint.
+  override def convertTo[Col[_]](implicit cbf: CanBuildFrom[Nothing, A, Col[A @uV]]): Col[A @uV] = {
+    val b = cbf()
+    b.sizeHint(this)
+    b ++= thisCollection
+    b.result
+  }
 
   /** Converts this $coll to a string.
    *
diff --git a/src/library/scala/collection/TraversableOnce.scala b/src/library/scala/collection/TraversableOnce.scala
index 386ce2d95a..8dc6184d88 100644
--- a/src/library/scala/collection/TraversableOnce.scala
+++ b/src/library/scala/collection/TraversableOnce.scala
@@ -9,6 +9,7 @@
 package scala.collection
 
 import mutable.{ Buffer, Builder, ListBuffer, ArrayBuffer }
+import generic.CanBuildFrom
 import annotation.unchecked.{ uncheckedVariance => uV }
 import language.{implicitConversions, higherKinds}
 import reflect.ClassTag
@@ -239,17 +240,25 @@ trait TraversableOnce[+A] extends Any with GenTraversableOnce[A] {
 
   def toTraversable: Traversable[A]
 
-  def toList: List[A] = (new ListBuffer[A] ++= seq).toList
+  def toList: List[A] = convertTo[List]
 
   def toIterable: Iterable[A] = toStream
 
   def toSeq: Seq[A] = toStream
 
-  def toIndexedSeq: immutable.IndexedSeq[A] = immutable.IndexedSeq() ++ seq
+  def toIndexedSeq: immutable.IndexedSeq[A] = convertTo[immutable.IndexedSeq]
 
-  def toBuffer[B >: A]: mutable.Buffer[B] = new ArrayBuffer[B] ++= seq
+  def toBuffer[B >: A]: mutable.Buffer[B] = convertTo[ArrayBuffer].asInstanceOf[mutable.Buffer[B]]
 
-  def toSet[B >: A]: immutable.Set[B] = immutable.Set() ++ seq
+  def toSet[B >: A]: immutable.Set[B] = convertTo[immutable.Set].asInstanceOf[immutable.Set[B]]
+
+  def toVector: Vector[A] = convertTo[Vector]
+
+  def convertTo[Col[_]](implicit cbf: CanBuildFrom[Nothing, A, Col[A @uV]]): Col[A @uV] = {
+    val b = cbf()
+    b ++= seq
+    b.result
+  }
 
   def toMap[T, U](implicit ev: A <:< (T, U)): immutable.Map[T, U] = {
     val b = immutable.Map.newBuilder[T, U]
diff --git a/src/library/scala/collection/immutable/Vector.scala b/src/library/scala/collection/immutable/Vector.scala
index 1395a8f52d..d100bf93df 100644
--- a/src/library/scala/collection/immutable/Vector.scala
+++ b/src/library/scala/collection/immutable/Vector.scala
@@ -77,6 +77,8 @@ override def companion: GenericCompanion[Vector] = Vector
 
   override def par = new ParVector(this)
 
+  override def toVector: Vector[A] = this
+
   override def lengthCompare(len: Int): Int = length - len
 
   private[collection] final def initIterator[B >: A](s: VectorIterator[B]) {
diff --git a/src/library/scala/collection/parallel/ParIterableLike.scala b/src/library/scala/collection/parallel/ParIterableLike.scala
index a447f1b5e4..a7ec833193 100644
--- a/src/library/scala/collection/parallel/ParIterableLike.scala
+++ b/src/library/scala/collection/parallel/ParIterableLike.scala
@@ -851,6 +851,12 @@ self: ParIterableLike[T, Repr, Sequential] =>
 
   override def toMap[K, V](implicit ev: T <:< (K, V)): immutable.ParMap[K, V] = toParMap[K, V, immutable.ParMap[K, V]](() => immutable.ParMap.newCombiner[K, V])
 
+  // TODO(@alex22): make these better
+  override def toVector: Vector[T] = seq.toVector
+
+  override def convertTo[Col[_]](implicit cbf: CanBuildFrom[Nothing, T, Col[T @uncheckedVariance]]): Col[T @uncheckedVariance] = seq.convertTo[Col]
+  
+
   /* tasks */
 
   protected trait StrictSplitterCheckTask[R, Tp] extends Task[R, Tp] {
diff --git a/src/library/scala/collection/parallel/immutable/ParVector.scala b/src/library/scala/collection/parallel/immutable/ParVector.scala
index 1ece663a1d..e4099f1809 100644
--- a/src/library/scala/collection/parallel/immutable/ParVector.scala
+++ b/src/library/scala/collection/parallel/immutable/ParVector.scala
@@ -62,6 +62,8 @@ extends ParSeq[T]
 
   override def seq: Vector[T] = vector
 
+  override def toVector: Vector[T] = vector
+
   class ParVectorIterator(_start: Int, _end: Int) extends VectorIterator[T](_start, _end) with SeqSplitter[T] {
     def remaining: Int = remainingElementCount
     def dup: SeqSplitter[T] = (new ParVector(remainingVector)).splitter