mandubian

sealed abstract trait Tree
case class Leaf(a: String) extends Tree
case class Node(l: Tree, r: Tree) extends Tree
 
implicit val treeR: Reads[Tree] =
__.read[Leaf].map(x => x:Tree) orElse
(
(__ \ "l").lazyRead(treeR) and (__ \ "r").lazyRead(treeR)
)(Node.apply _).map(x => x:Tree)
 

mandubian

import scala.annotation.StaticAnnotation
import scala.reflect.macros.Macro
import language.experimental.macros
 
class body(tree: Any) extends StaticAnnotation
 
trait Macros extends Macro {
  import c.universe._
 
  def selFieldImpl = {

mandubian

<put your code here>

mandubian

import play.api.libs.json._
import play.api.libs.functional.syntax._

val r = (
  (__ \ "field1").readNullable[String] and 
  (__ \ "field2").readNullable[Int]
).tupled.filter(ValidationError("unexpected result")){ 
  case( Some(x), None ) => true; 
  case ( None, Some(x) ) => true; 
  case _ => false 

mandubian

case class Foo(bar: String)

// extends Function1 is just to workaround a limitation in Play2.1
object Foo extends Function1(bar: String, Foo) { 
  implicit val fmt = Json.format[Foo]
}

mandubian

<put your code here>

mandubian

import play.api.libs.json._

val reads = (__ \ "foo").read[String] orElse Reads.pure("default string")

mandubian

test

mandubian

mon implementation à moi qui tue!