JsonParser.scala

package challenge

import intro._
import challenge.MoreParser._

sealed trait Json
case class JsonString(value: String) extends Json
case class JsonNumber(value: Double) extends Json
case class JsonObject(value: List[(String, Json)]) extends Json
case class JsonArray(value: List[Json]) extends Json
case class JsonBoolean(value: Boolean) extends Json
case object JsonNull extends Json

sealed trait SpecialCharacter {

  def toChar: Char =
    this match {
      case BackSpace =>
        '\b'
      case FormFeed =>
        '\f'
      case NewLine =>
        '\n'
      case CarriageReturn =>
        '\r'
      case Tab =>
        '\t'
      case VerticalTab =>
        '\u000b'
      case SingleQuote =>
        '\''
      case DoubleQuote =>
        '"'
      case Backslash =>
        '\\'
    }
}
case object BackSpace extends SpecialCharacter
case object FormFeed extends SpecialCharacter
case object NewLine extends SpecialCharacter
case object CarriageReturn extends SpecialCharacter
case object Tab extends SpecialCharacter
case object VerticalTab extends SpecialCharacter
case object SingleQuote extends SpecialCharacter
case object DoubleQuote extends SpecialCharacter
case object Backslash extends SpecialCharacter

object JsonParser {

  def toSpecialChar(c: Char): Optional[SpecialCharacter] =
    c match {
      case 'b' =>
        Full(BackSpace)
      case 'f' =>
        Full(FormFeed)
      case 'n' =>
        Full(NewLine)
      case 'r' =>
        Full(CarriageReturn)
      case 't' =>
        Full(Tab)
      case 'v' =>
        Full(VerticalTab)
      case '\'' =>
        Full(SingleQuote)
      case '"'  =>
        Full(DoubleQuote)
      case '\\' =>
        Full(Backslash)
      case _ =>
        Empty()
    }

  /**
   * Parse a JSON string. Handle double-quotes, special characters, hexadecimal characters.
   *
   * See http://json.org for the full list of control characters in JSON.
   * Feel free to keep it simple * to start with to pass the basic tests.
   *
   * scala> JsonParser.stringParser.parseAll("\"abc\"")
   *  = Ok(abc)
   *
   * scala> JsonParser.stringParser.parseAll("\" abc\"")
   *  = Ok( abc)
   */
  def stringParser: Parser[String] =
    ???

  /**
   * Parse a JSON rational number.
   *
   * Feel free to start by parsing natural numbers (int), and move on to the rest of the challenge.
   *
   * scala> JsonParser.numberParser.parseAll("123")
   *  = Ok(123)
   *
   * scala> JsonParser.numberParser.parseAll("123.4")
   *  = Ok(123.4)
   *
   * scala> JsonParser.numberParser.parseAll("-123")
   *  = Ok(-123)
   */
  def numberParser: Parser[Double] =
    ???

  /**
   * Parse a JSON boolean value.
   *
   * Tip: Use `string` and `|||`
   *
   * scala> JsonParser.booleanParser.parseAll("true")
   *  = Ok(true)
   *
   * scala> JsonParser.booleanParser.parseAll("false")
   *  = Ok(false)
   */
  def booleanParser: Parser[Boolean] =
    ???

  /**
   * Parse a JSON `null` literal.
   *
   * Tip: Use `string`
   *
   * scala> JsonParser.nullParser.parseAll("null")
   *  = Ok(())
   */
  def nullParser: Parser[Unit] =
    ???

  /**
   * Parse a JSON array.
   *
   * Tip: Use `sepBy` and `jsonParser`
   *
   * scala> JsonParser.arrayParser.parseAll("""["1", 2, true]""")
   *  = Ok(List(JsonString(1),JsonNumber(2),JsonBoolean(true)))
   *
   * scala> JsonParser.arrayParser.parseAll("[]")
   *  = Ok(List())
   */
  def arrayParser: Parser[List[Json]] =
    ???

  /**
   * Parse a JSON object.
   *
   * Tip: Use `jsonString`, `sepBy` and `jsonParser`
   *
   * scala> JsonParser.objectParser.parseAll("""{"a":"x","b":2,"c":true}""")
   *  = Ok(List((a,JsonString("x")),(b,JsonNumber(2)),(c,JsonBoolean(true))))
   *
   * scala> JsonParser.objectParser.parseAll("")
   *  = Ok(List())
   *
   */
  def objectParser: Parser[List[(String, Json)]] =
    ???

  /**
   * Parse a JSON value.
   *
   * Tip: Use the other parsers and `|||`
   *
   * scala> JsonParser.jsonParser.parseAll("""{"key1":true}""")
   *  = Ok(JsonObject(List((key1,JsonBoolean(true))))
   *
   * scala> JsonParser.jsonParser.parseAll("""{"key1":true,"key2":[7,false]}""")
   *  = Ok(JsonObject(List((key1,JsonBoolean(true)),(key2,JsonArray(List(JsonNumber(7), JsonBoolean(false)))))))
   *
   * scala> JsonParser.jsonParser.parseAll("""{"key1":true,"key2":[7,false],"key3":{"key4":null}}""")
   *  = Ok(JsonObject(List((key1,JsonBoolean(true)),(key2,JsonArray(List(JsonNumber(7), JsonBoolean(false)))),(key3,JsonObject(List((key4,JsonNull))))
   */
  def jsonParser: Parser[Json] =
    ???
}