[squash] non-anonymous Iterator

Author: NthPortal

src/library/scala/collection/Iterable.scala

@@ -714,14 +714,6 @@ object IterableOps {
 object Iterable extends IterableFactory.Delegate[Iterable](immutable.Iterable) {
   implicit def toLazyZipOps[A, CC[X] <: Iterable[X]](that: CC[A]): LazyZipOps[A, CC[A]] = new LazyZipOps(that)
 
-  /** An `Iterable` that calls [[scala.collection.Iterator.unfold `Iterator.unfold`]]
-    * to create `Iterator`s.
-    */
-  private final class UnfoldIterable[A, S] private(initial: S)(f: S => Option[(A, S)])
-    extends AbstractIterable[A] {
-    override def iterator: Iterator[A] = Iterator.unfold(initial)(f)
-  }
-
   /**
     * @return an Iterable by using a function `f` producing elements of
     *         type `A` and updating an internal state `S`.
@@ -731,7 +723,14 @@ object Iterable extends IterableFactory.Delegate[Iterable](immutable.Iterable) {
     * @tparam A   Type of the elements
     * @tparam S   Type of the internal state
     */
-  def unfold[A, S](init: S)(f: S => Option[(A, S)]): Iterable[A] = new UnfoldIterable[A, S](init)(f)
+  def unfold[A, S](init: S)(f: S => Option[(A, S)]): Iterable[A] = new UnfoldIterable(init)(f)
+
+  /** An `Iterable` that calls [[scala.collection.Iterator.unfold `Iterator.unfold`]]
+    * to create `Iterator`s.
+    */
+  private final class UnfoldIterable[A, S](initial: S)(f: S => Option[(A, S)]) extends AbstractIterable[A] {
+    override def iterator: Iterator[A] = Iterator.unfold(initial)(f)
+  }
 }
 
 /** Explicit instantiation of the `Iterable` trait to reduce class file size in subclasses. */

src/library/scala/collection/Iterator.scala

@@ -967,27 +967,7 @@ object Iterator extends IterableFactory[Iterator] {
     * @tparam A   Type of the elements
     * @tparam S   Type of the internal state
     */
-  def unfold[A, S](init: S)(f: S => Option[(A, S)]): Iterator[A] = new AbstractIterator[A] {
-    private[this] var state: S = init
-    private[this] var nextResult: Option[(A, S)] = null
-
-    override def hasNext: Boolean = {
-      if (nextResult eq null) {
-        nextResult = Objects.requireNonNull(f(state), "null during unfold")
-        state = null.asInstanceOf[S] // allow GC
-      }
-      nextResult.isDefined
-    }
-
-    override def next(): A = {
-      if (hasNext) {
-        val (value, newState) = nextResult.get
-        state = newState
-        nextResult = null
-        value
-      } else Iterator.empty.next()
-    }
-  }
+  def unfold[A, S](init: S)(f: S => Option[(A, S)]): Iterator[A] = new UnfoldIterator(init)(f)
 
   /** Creates an iterator to which other iterators can be appended efficiently.
     *  Nested ConcatIterators are merged to avoid blowing the stack.
@@ -1108,6 +1088,31 @@ object Iterator extends IterableFactory[Iterator] {
     }
   }
 
+  /** `Iterator` which uses a function `f` to produce elements of
+    * type `A` and update an internal state `S`.
+    */
+  private final class UnfoldIterator[A, S](init: S)(f: S => Option[(A, S)]) extends AbstractIterator[A] {
+    private[this] var state: S = init
+    private[this] var nextResult: Option[(A, S)] = null
+
+    override def hasNext: Boolean = {
+      if (nextResult eq null) {
+        nextResult = Objects.requireNonNull(f(state), "null during unfold")
+        state = null.asInstanceOf[S] // allow GC
+      }
+      nextResult.isDefined
+    }
+
+    override def next(): A = {
+      if (hasNext) {
+        val (value, newState) = nextResult.get
+        state = newState
+        nextResult = null
+        value
+      } else Iterator.empty.next()
+    }
+  }
+
   // scalac generates a `readReplace` method to discard the deserialized state (see https://github.com/scala/bug/issues/10412).
   // This prevents it from serializing it in the first place:
   private[this] def writeObject(out: ObjectOutputStream): Unit = ()