Pretty Print method for formatting case class (as a string input)

prettyPrint.scala

def pp(tree: String, indentSize: Int = 2): String = {
  var indentLevel = 0
  var outputTree = ""
  tree foreach { char => char match {
    case '(' =>
      indentLevel += 1
      outputTree += char.toString+'\n'+indents
    case ')' =>                     
      indentLevel -= 1
      outputTree += "\n" + indents + char.toString
    case ',' => outputTree += char.toString + "\n" + indents
    case _   => outputTree += char.toString
  }}

  def indents = " " * indentLevel * indentSize

  outputTree
}

val asdf = """Argument(Expr(List(EqualsExpr(List(CallExpr(None, Token(VARID, firstGroup2, 34, firstGroup2 ), None, List(), None ) ), Token(EQUALS,=,46,= ), Expr(List(GeneralTokens(List(Token(STRING_LITERAL,"One",48,"One") ) ) ) ) ) ) ) )"""

pp(asdf)