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Diffstat (limited to 'src')
-rw-r--r-- | src/library/scala/collection/immutable/Stream.scala | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/src/library/scala/collection/immutable/Stream.scala b/src/library/scala/collection/immutable/Stream.scala index cf9a48983a..5339b29e7c 100644 --- a/src/library/scala/collection/immutable/Stream.scala +++ b/src/library/scala/collection/immutable/Stream.scala @@ -245,6 +245,30 @@ self => new StreamWithFilter(x => p(x) && q(x)) } + /** See #3273 and test case run/bug3273 for motivation. */ + final class StreamIterator extends Iterator[A] { + // A call-by-need cell. + class LazyCell(st: => Stream[A]) { + lazy val v = st + } + + private var these = new LazyCell(self) + def hasNext: Boolean = these.v.nonEmpty + def next: A = + if (isEmpty) Iterator.empty.next + else { + val cur = these.v + val result = cur.head + these = new LazyCell(cur.tail) + result + } + override def toStream = these.v + override def toList = toStream.toList + } + + /** A lazier Iterator than LinearSeqLike's. */ + override def iterator: Iterator[A] = new StreamIterator + /** Apply the given function <code>f</code> to each element of this linear sequence * (while respecting the order of the elements). * |