simple (uber-hacky) json renderer in 40 lines of scala

JSONRenderer.scala

import scala.collection.immutable.Map

/*
  simple (uber-hacky) json renderer in 40 lines of scala
  http://github.com/paulasmuth

  usage: 

    JSONRenderer.render(Map(
      "a_string"  -> "fnord", 
      "an_array"  -> List(1,2,3),
      "2nd_level" -> Map("fu" -> "bar")
    )).toString

  output:

    { 
      "a_string": "fnord", 
      "an_array": [ 1, 2, 3 ], 
      "2nd_level": { "fu": "bar" } 
    }
        
*/

object JSONRenderer{

  class JSONObject(raw: String){
    override def toString() = raw
  }


  def render(in: Any) : String = { in match {
    case str: String     => render_string(str)
    case lst: List[Any]  => render_list(lst)
    case int: Integer    => render_num(int.toLong)
    case lng: Long       => render_num(lng)
    case obj: JSONObject => obj.toString
    case obj: Map[String, Any] => render_obj(obj).toString
  }}
  

  def render_obj(src: Map[String, Any]) : JSONObject =
    new JSONObject("{ " + (render_values(src) reduceLeft (
      (s: String, c: String) => s + ", " + c )) + " }")


  private def render_values(src: Map[String, Any]) : List[String] =
    (src toList) map (
      (c: (String, Any)) => 
        render_string(c._1) + ": " + render(c._2).toString)


  private def render_string(str: String) : String =
    "\"" + str.replaceAll("\"", "\\\\\"") + "\""


  private def render_list(lst: List[Any]) : String = 
    (("[ " /: lst.view.zipWithIndex)(
      (s: String, c: (Any, Int)) => 
        s + render(c._1) + (
          if (c._2 < lst.size - 1) ", " else "")) + " ]")


  private def render_num(num: Long) : String = num.toString

}