gistfile1.scala

/* Finds the version history of a POM in a Subversion repository */

import scala.sys.process.Process

object Conf {
  val url = "put the url of your POM here"
  val svn = "svn --username xxx"
}

case class Revision(number: Int, date: String, version: String) {
  override def toString = productIterator.mkString("; ")
}

def removeConsecutiveDuplicates[A](s: Stream[A], same: (A, A) => Boolean): Stream[A] =
  if (s.isEmpty) s else
    Stream.cons(s.head, removeConsecutiveDuplicates(s.dropWhile(same(s.head, _)), same))

def pomVersions(start: String, end: String) = {

  val runSvnLog = Conf.svn + " log " + Conf.url + " -r" + start + ":" + end
  val svnLogPattern = """^r(\d+) \| \w+ \| (.*) \+""".r
  val pomVersionPattern = "<version>(.*)</version>".r

  def pomVersionAt(revision: Int) = {
    val runSvnCat = Conf.svn + " cat " + Conf.url + " -r" + revision
    val pomContents = Process(runSvnCat).!!
    pomVersionPattern.findFirstMatchIn(pomContents).map(_.group(1)).getOrElse("no version found")
  }

  val revisions = for {
    line <- Process(runSvnLog).lines
    m <- svnLogPattern.findFirstMatchIn(line)
    number = m.group(1).toInt
    date = m.group(2)
    version = pomVersionAt(number)
  } yield Revision(number, date, version)

  def sameVersion(r1: Revision, r2: Revision) = r1.version == r2.version
  removeConsecutiveDuplicates(revisions, sameVersion)
}

println(pomVersions("12000", "HEAD").mkString("\n"))