Interpreter result type not found despite importing it

Question

I use Scala 2.9.1. I have a simple scala "interpreter":

import scala.tools.nsc.interpreter.IMain
import scala.tools.nsc.interpreter.Results.Result
import scala.tools.nsc.interpreter.Results.Success

object App {

  def main(args: Array[String]) {
    val interpreter = new IMain
    val result:Result = interpreter.interpret(args(0))
    result.toString() match {
      case "Success" =>
        {
          var success = result.asInstanceOf[Success]
          println(success.productElement(0))
        };
      case _ => println("very bad result");
    }
  }

}

When i try to compile it (maven) i get:

[ERROR] /home/koziolek/workspace/dsi/src/main/scala/pl/koziolekweb/scala/dsi/App.scala:15: error: not found: type Success
[INFO]           var success = result.asInstanceOf[Success]

As you can see, the compiler said that there is no type Success, although I imported it.

For a test, can you import the Success in the line just before `var success = results.asInstanceOf[Success]`? — Furbeenator, Dec 09 '11 at 22:31

score 7 · Accepted Answer · edited May 23 '17 at 12:19

Success is an object, not a class, you would need to cast it to its singleton type result.asInstanceOf[Success.type]. Obviously you are trying to work around not knowing how to do the pattern match. That would allow you to get the right result without casting:

import tools.nsc.interpreter.Results._

result match {
   case Success    => "yes!"
   case Error      => "no..."
   case Incomplete => "you missed something"
}

If you want to get the resulting value of the interpreted expression in the case of success, see my reply in this post for more details.

Interpreter result type not found despite importing it

1 Answers1