Treee.scala

package org.pblue.treee

case class Node[T](var value: T, var children: List[Node[T]])

trait Treee[T] {

	val root: Node[T]

	def filter(pred: T => Boolean): List[Node[T]]

}

class TreeeImpl[T](val root: Node[T]) extends Treee[T] {

	private def flatten(node: Node[T]): List[Node[T]] =
		node :: node.children.flatMap(flatten(_))

	val nodes = flatten(root)

	def filter(pred: T => Boolean) = nodes.filter(n => pred(n.value))

}

object XmlTreee {
	def wrap(node: scala.xml.Node): Node[scala.xml.Node] = {
		val wrapped = Node(node, List())
		wrapped.children = node.child.map(wrap(_)).toList
		wrapped
	}

	def apply(node: scala.xml.Node) = new TreeeImpl(wrap(node))

	def unwrap(node: Node[scala.xml.Node]): scala.xml.Node = {
		val unwrapped = node.value
		unwrapped match {
			case e: scala.xml.Elem =>
				val children = node.children.map(unwrap(_))
				e.copy(child = children)
			case n => n
		}
	}

	def build(treee: TreeeImpl[scala.xml.Node]) = unwrap(treee.root)

	def update(node: Node[scala.xml.Node], newElem: scala.xml.Node) = {
		val wrapped = wrap(newElem)
		node.value = newElem
		node.children = wrapped.children
	}
}

// how to use

object Main {
	def main(args: Array[String]) {
		val xml =
<pisa foo="bar">
	<kaka hello="world">
		mivan MIVAN MIVAN?!!?!
	</kaka>
	<fika foo="nembar"><fos></fos></fika>
</pisa>

		println(xml)

		val replacement = <fing>:DDDDD</fing>
		println
		println(s"replacing with $replacement")

		val treee = XmlTreee(xml)
		val selectedNodes = treee.filter(elem => elem.label == "fika")
		selectedNodes.foreach(XmlTreee.update(_, replacement))
		val newXml = XmlTreee.build(treee)

		println()
		println(newXml)
	}
}