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List Zipper
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case class ListZipper[+A](lefts: List[A], x: A, rights: List[A]) { | |
def map[B](f: A => B): ListZipper[B] = | |
sys.error("todo") | |
// map with zipper context | |
def coFlatMap[B](f: ListZipper[A] => B): ListZipper[B] = | |
sys.error("todo") | |
def findRight(p: A => Boolean): Option[ListZipper[A]] = | |
sys.error("todo") | |
def findLeft(p: A => Boolean): Option[ListZipper[A]] = | |
sys.error("todo") | |
def :=[AA >: A](a: AA): ListZipper[AA] = | |
ListZipper(lefts, a, rights) | |
def toList: List[A] = | |
lefts.reverse ::: x :: rights | |
} | |
object ListZipper { | |
def fromList[A](a: List[A]): Option[ListZipper[A]] = | |
a match { | |
case Nil => None | |
case h::t => Some(ListZipper(Nil, h, t)) | |
} | |
} |
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