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* Copyright 2009-2010 WorldWide Conferencing, LLC
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
package net.liftweb.json.scalaz
import scalaz._
import Scalaz._
import net.liftweb.json._
trait Types {
type Result[A] = ValidationNEL[Error, A]
sealed trait Error
case class UnexpectedJSONError(was: JValue, expected: Class[_ <: JValue]) extends Error
case class NoSuchFieldError(name: String, json: JValue) extends Error
case class UncategorizedError(key: String, desc: String, args: List[Any]) extends Error
case object Fail {
def apply[A](key: String, desc: String, args: List[Any]): Result[A] =
UncategorizedError(key, desc, args).fail.liftFailNel
def apply[A](key: String, desc: String): Result[A] =
UncategorizedError(key, desc, Nil).fail.liftFailNel
implicit def JValueShow[A <: JValue]: Show[A] = new Show[A] {
def show(json: A) = compact(render(json)).toList
implicit def JValueZero: Zero[JValue] = zero(JNothing)
implicit def JValueSemigroup: Semigroup[JValue] = semigroup(_ ++ _)
implicit def JValueEqual: Equal[JValue] = equalA
trait JSONR[A] {
def read(json: JValue): Result[A]
trait JSONW[A] {
def write(value: A): JValue
trait JSON[A] extends JSONR[A] with JSONW[A]
implicit def Result2JSONR[A](f: JValue => Result[A]): JSONR[A] = new JSONR[A] {
def read(json: JValue) = f(json)
def fromJSON[A: JSONR](json: JValue): Result[A] = implicitly[JSONR[A]].read(json)
def toJSON[A: JSONW](value: A): JValue = implicitly[JSONW[A]].write(value)
def field[A: JSONR](name: String)(json: JValue): Result[A] = json match {
case JObject(fs) =>
fs.find( == name)
.map(f => implicitly[JSONR[A]].read(f.value))
.orElse(implicitly[JSONR[A]].read(JNothing).fold(_ => none, x => some(Success(x))))
.getOrElse(NoSuchFieldError(name, json).fail.liftFailNel)
case x => UnexpectedJSONError(x, classOf[JObject]).fail.liftFailNel
def validate[A: JSONR](name: String): Kleisli[Result, JValue, A] = kleisli(field[A](name))
def makeObj(fields: Traversable[(String, JValue)]): JObject =
JObject( { case (n, v) => JField(n, v) })
object JsonScalaz extends Types with Lifting with Base with Tuples
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