scala RichNodeSeq

RichNodeSeq.scala

// extend scala.xml.NodeSeq to support xpath with attr
// call-seq:  ex.RichNodeSeq(<a id="2"/><a/>) \ "a[id=2]"
package ex

import scala.xml._

case class RichNodeSeq(nodeSeq: NodeSeq) extends NodeSeq {
  def theSeq = nodeSeq.theSeq
  
  private val attrRe = """^\s*(.*)\s*\[\s*(.*)\s*=\s*(.*)\s*\]$""".r

  private def isElemWithAttr(elem: String, attr: String, value: String) =
    (node: Node) => (node.label == elem) && (node attribute attr map (_(0) == value) getOrElse false)

  override def \ (that: String): NodeSeq = that match {
    case attrRe(elem, attr, value) =>
      flatMap (_.child) filter isElemWithAttr(elem, attr, value)
    case _ => super.\(that) // .()required
  }

  override def \\ (that: String): NodeSeq = that match {
    case attrRe(elem, attr, value) =>
      flatMap (_.descendant_or_self) filter isElemWithAttr(elem, attr, value)
    case _ => super.\\(that)
  }
}