package foo

import scala.language.dynamics

object Caller extends App {
  val client = new Client() // initialise an R interpreter
  client.x = 1.0
}
class Client extends Dynamic {
  var map = Map.empty[String, Any]
  def selectDynamic(name: String) = map get name getOrElse sys.error("field not found")
  def updateDynamic(name: String)(value: Any) { map += name -> value }
}

scalaVersion := "2.10.6"

libraryDependencies++= Seq(
  "org.scalanlp" %% "breeze" % "0.12"
)

[error] /home/philwalk/dynsbt/src/main/scala/foo/Caller.scala:8: type mismatch;
[error]  found   : foo.Caller.client.type (with underlying type foo.Client)
[error]  required: ?{def x: ?}
[error] Note that implicit conversions are not applicable because they are ambiguous:
[error]  both method any2Ensuring in object Predef of type [A](x: A)Ensuring[A]
[error]  and method any2ArrowAssoc in object Predef of type [A](x: A)ArrowAssoc[A]
[error]  are possible conversion functions from foo.Caller.client.type to ?{def x: ?}
[error]   client.x = Seq("a","b","c")
[error]   ^
[error] one error found
[error] (compile:compileIncremental) Compilation failed
[error] Total time: 3 s, completed May 3, 2016 11:03:08 AM

client.x = 1.0

client.xx = 1.0