StackOverflowで見つけた 標準のライブラリで JSON 扱う サンプル

stdjson_ex1.scala

// JSON use std lib.
// StackOverflowで見つけた 標準のライブラリで JSON 扱う サンプル
// how-to-parse-json-in-scala-using-standard-scala-classes
// http://stackoverflow.com/questions/4170949/

import scala.util.parsing.json._

// jsonデータサンプル
val jsonString = """{"languages":[{"name":"japanese","is_active":true,"completeness": 1.0,"books":{"title":"title1","author":"neko"}},{"name":"english","is_active":true,"completeness": 2.0,"books":{"title":"title2","author":"Dog"}}]}"""

class CC[T] { def unapply(a:Any):Option[T] = Some(a.asInstanceOf[T]) }

object M extends CC[Map[String, Any]]
object L extends CC[List[Any]]
object S extends CC[String]
object D extends CC[Double]
object B extends CC[Boolean]

for {
    Some(M(map)) <- List(JSON.parseFull(jsonString))
    L(languages) = map("languages")
    M(language) <- languages
    S(name) = language("name")
    B(active) = language("is_active")
    D(completeness) = language("completeness")
    M(books) = language("books")
    S(title) = books("title")
} yield {
    (name, active, completeness, title)
}