Scala example source code file (JSON.scala)

This example Scala source code file (JSON.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

any, any, array, array, json, json1, map, parser, parser, standardtokenparsers, standardtokenparsers

The Scala JSON.scala source code

package examples.parsing

import scala.util.parsing.combinator1.syntactical.StandardTokenParsers

object JSON extends StandardTokenParsers {   
  lexical.delimiters += ("{", "}", "[", "]", ":", ",")
  lexical.reserved += ("null", "true", "false")

  def obj   : Parser[Any] = "{" ~ repsep(member, ",") ~ "}"
  def arr   : Parser[Any] = "[" ~ repsep(value, ",") ~ "]"
  def member: Parser[Any] = ident ~ ":" ~ value
  def value : Parser[Any] = ident | numericLit | obj | arr | 
                            "null" | "true" | "false"

  def main(args: Array[String]) {
    val tokens = new lexical.Scanner(args(0))
    println(args(0))
    println(phrase(value)(tokens))
  }
}
object JSON1 extends StandardTokenParsers {   
  lexical.delimiters += ("{", "}", "[", "]", ":", ",")
  lexical.reserved += ("null", "true", "false")

  def obj: Parser[Map[String, Any]] = 
    "{" ~> repsep(member, ",") <~ "}" ^^ (Map() ++ _)

  def arr: Parser[List[Any]] =
    "[" ~> repsep(value, ",") <~ "]" 

  def member: Parser[(String, Any)] = 
    ident ~ ":" ~ value ^^ { case name ~ ":" ~ value => (name -> value) }

  def value: Parser[Any] = 
    ident | numericLit ^^ (_.toInt) | obj | arr |
    "null" ^^^ null | "true" ^^^ true | "false" ^^^ false

  def main(args: Array[String]) {
    val tokens = new lexical.Scanner(args(0))
    println(args(0))
    println(phrase(value)(tokens))
  }
}