diff options
Diffstat (limited to 'src/library/scala/collection/SeqViewLike.scala')
-rw-r--r-- | src/library/scala/collection/SeqViewLike.scala | 22 |
1 files changed, 10 insertions, 12 deletions
diff --git a/src/library/scala/collection/SeqViewLike.scala b/src/library/scala/collection/SeqViewLike.scala index 3473c8aff1..1fbcb6531e 100644 --- a/src/library/scala/collection/SeqViewLike.scala +++ b/src/library/scala/collection/SeqViewLike.scala @@ -96,6 +96,14 @@ trait SeqViewLike[+A, if (idx < self.length) self(idx) else restSeq(idx - self.length) } + trait Prepended[B >: A] extends super.Prepended[B] with Transformed[B] { + protected[this] lazy val fstSeq = fst.toSeq + def length: Int = fstSeq.length + self.length + def apply(idx: Int): B = + if (idx < fstSeq.length) fstSeq(idx) + else self.apply(idx - fstSeq.length) + } + trait Filtered extends super.Filtered with Transformed[A] { protected[this] lazy val index = { var len = 0 @@ -179,21 +187,12 @@ trait SeqViewLike[+A, final override protected[this] def viewIdentifier = "P" } - trait Prepended[B >: A] extends Transformed[B] { - protected[this] val fst: B - override def iterator: Iterator[B] = Iterator.single(fst) ++ self.iterator - def length: Int = 1 + self.length - def apply(idx: Int): B = - if (idx == 0) fst - else self.apply(idx - 1) - final override protected[this] def viewIdentifier = "A" - } - /** Boilerplate method, to override in each subclass * This method could be eliminated if Scala had virtual classes */ protected override def newForced[B](xs: => GenSeq[B]): Transformed[B] = new { val forced = xs } with AbstractTransformed[B] with Forced[B] protected override def newAppended[B >: A](that: GenTraversable[B]): Transformed[B] = new { val rest = that } with AbstractTransformed[B] with Appended[B] + protected override def newPrepended[B >: A](that: GenTraversable[B]): Transformed[B] = new { protected[this] val fst = that } with AbstractTransformed[B] with Prepended[B] protected override def newMapped[B](f: A => B): Transformed[B] = new { val mapping = f } with AbstractTransformed[B] with Mapped[B] protected override def newFlatMapped[B](f: A => GenTraversableOnce[B]): Transformed[B] = new { val mapping = f } with AbstractTransformed[B] with FlatMapped[B] protected override def newFiltered(p: A => Boolean): Transformed[A] = new { val pred = p } with AbstractTransformed[A] with Filtered @@ -212,7 +211,6 @@ trait SeqViewLike[+A, val patch = _patch val replaced = _replaced } with AbstractTransformed[B] with Patched[B] - protected def newPrepended[B >: A](elem: B): Transformed[B] = new { protected[this] val fst = elem } with AbstractTransformed[B] with Prepended[B] // see comment in IterableViewLike. protected override def newTaken(n: Int): Transformed[A] = newSliced(SliceInterval(0, n)) @@ -242,7 +240,7 @@ trait SeqViewLike[+A, } override def +:[B >: A, That](elem: B)(implicit bf: CanBuildFrom[This, B, That]): That = - newPrepended(elem).asInstanceOf[That] + newPrepended(elem :: Nil).asInstanceOf[That] override def :+[B >: A, That](elem: B)(implicit bf: CanBuildFrom[This, B, That]): That = ++(Iterator.single(elem))(bf) |