小编use*_*564的帖子

我试图在scala中为匿名函数设置默认值,因此无法找到任何解决方案.希望有人能帮助我.

我有以下结构,

case class A(id:Int = 0)

case class B(a:A)

object B {
     def func1(f:Int = 0)={
      ........
     }
 def func2(f:A => B = (how to give default value ?))={
        case Nothing => {
         //do something....
        }
        case _ => {
         //do some other thing......
        }
 }
} 

基本上,我想将参数作为可选参数传递.我怎样才能做到这一点？

我有一个示例代码如下.

import play.api.libs.json._
import play.api.libs.functional.syntax._
import play.api.data.validation.ValidationError
import play.api.libs.json.Reads._

case class Retailer(firstName:String,lastName:String,email:String,mobileNo:String,password:String)
case class Business(name:String,preferredUrl:String,businessPhone:String,retailer:Retailer)

object JsonTest {
  val jsonValue = """
  {
    "business":
    {
      "name":"Some Business Name",
      "preferredUrl":"someurl",
      "businessPhone":"somenumber",
      "retailer":
      {
        "firstName":"Some",
        "lastName":"One",
        "email":"someone@somewhere.com",
        "mobileNo":"someothernumber",
        "password":"$^^HFKH*"
      }
    }

  }
  """
  def printJson ={

    implicit val rltRds = (
      (__ \ "firstName").read[String] ~
      (__ \ "lastName").read[String] ~
      (__ \ "email").read[String] ~
      (__ \ "mobileNo").read[String] ~
      (__ \ "password").read[String]
    )(Retailer)    

    implicit val bsnsRds = (
      (__ \ "name").read[String] ~
      (__ \ …