Update Path.scala

Author: pawelsadlo

os/src/Path.scala

@@ -26,10 +26,15 @@ object PathChunk extends PathChunkMacros {
     val splitted = strNoTrailingSeps.split('/')
     splitted ++ Array.fill(trailingSeparatorsCount)("")
   }
-
+  private def reduceUps(in:List[String]) = in.foldLeft(List.empty[String]){case (acc,x) => 
+	   acc match{
+	     case h :: t if h == ".." => x :: acc
+	     case h :: t if x == ".." => t
+	     case _ => x :: acc}
+	 }.reverse
   private[os] def segmentsFromStringLiteralValidation(literal: String): Array[String] = {
     val stringSegments = segmentsFromString(literal)
-    val validSegmnts = validLiteralSegments(stringSegments)
+    val validSegmnts = reduceUps(validLiteralSegments(stringSegments))
     val sanitizedLiteral = validSegmnts.mkString("/")
     if (validSegmnts.isEmpty) throw InvalidSegment(
       literal,