case-class

How should I extract the value of a field of a case class from a given String value representing the field. For example: case class Person(name: String, age: Int) val a = Person("test",10) Now here given a string name or age i want to extract the value from variable a . How do i do this? I know this can be done using reflection but I am not exactly sure how? Yuval Itzchakov What you're looking for can be achieve using Shapeless lenses. This will also put the constraint that a field actually exists on a case class at compile time rather than run time: import shapeless._ case class Person(name:

I have a simple class hierarchy that represents a graph-like structure with several distinct types of vertexes implemented using case classes: sealed trait Node sealed abstract case class Vertex extends Node case class Arc extends Node case class VertexType1 (val a:Int) extends Vertex case class VertexType2 (val b:Int) extends Vertex This allows me to write match blocks like this: def test (x: Node) = x match { case _ : Arc => "got arc" case _ : Vertex => "got vertex" } or like this: def test (x: Node) = x match { case _ : Arc => "got arc" case c : Vertex => c match { case _ : VertexType1(a) =

I am trying to do the following trait Stateful { type State } case class SystemState(system: Stateful, state: system.State) // does not compile That is, the type of state depends on (the value of) system . That, however, is not supported: illegal dependent method type: parameter appears in the type of another parameter in the same section or an earlier one With function arguments, I could split the arguments into two argument lists, which is not possible with a case class constructor: def f(system: Stateful)(state: system.State): Unit = {} // compiles The best I can do is: case class

Given a string of JSON, and a case class that corresponds to it, what's a simple way to parse the JSON into the case class? There are many libraries available, but it seems that Scala might now do this out of the box. What about if the JSON should be parsed into a list of the case class? UPDATE: Jerkson seems to be abandoned, and I don't want to install the full Play or Lift framework or anything else heavy. There are several frameworks which can exactly do that. circe Used a lot nowdays. Many great features. Will pull cats in. https://circe.github.io/circe/ https://github.com/circe/circe