teresamoose
New Member
I'm trying to replace pieces of XML and need an accumulator along the way. Say I have a fill-in-the-blank question stored as XML like so:\[code\]val q = <text>The capitals of Bolivia are <blank/> and <blank/>.</text>\[/code\]At some point I'm going to want to turn those blanks into HTML input elements and I need to be able to distinguish the first and second so I can check them. (Ignore the fact that, in this case, the two capitals can appear in either order--that's a headache I'll deal with later.)Thanks to some lovely answers on StackOverflow, I produced the following solution:\[code\]import scala.xml._import scala.xml.transform._class BlankReplacer extends BasicTransformer { var i = 0 override def transform(n: Node): NodeSeq = n match { case <blank/> => { i += 1 <input name={ "blank.%d".format(i) }/> } case elem: Elem => elem.copy(child=elem.child.flatMap(transform _)) case _ => n }}\[/code\]and this works reasonably well. I have to create a \[code\]new BlankReplacer()\[/code\] each time I want to start re-numbering, but it pretty much works:\[code\]scala> new BlankReplacer()(q)res6: scala.xml.Node = <text>The capitals of Bolivia are <input name="blank.1"></input> and <input name="blank.2"></input>.</text>\[/code\]Here's the question. Is there an easy way to avoid the mutation I have to do each time I replace a \[code\]<blank/>\[/code\]? What I have doesn't strike me as horrible, but I think this could be cleaner if I weren't creating a new instance of the \[code\]BlankReplacer\[/code\] class every time I had to convert a question to HTML. I'm sure there's some way to turn this into an accumulator, but I'm not sure how to do it.Thanks!Todd