Scala equivalent of C#’s extension methods?

Question

In C# you can write:

using System.Numerics; namespace ExtensionTest { public static class MyExtensions {     public static BigInteger Square(this BigInteger n) {         return n * n;     }     static void Main(string[] args) {         BigInteger two = new BigInteger(2);         System.Console.WriteLine("The square of 2 is " + two.Square());     } }} 

How would this simple extension method look like in Scala?

Answer 1

The Pimp My Library pattern is the analogous construction:

object MyExtensions {   implicit def richInt(i: Int) = new {     def square = i * i   } }   object App extends Application {   import MyExtensions._    val two = 2   println("The square of 2 is " + two.square)  } 

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Per @Daniel Spiewak's comments, this will avoid reflection on method invocation, aiding performance:

object MyExtensions {   class RichInt(i: Int) {     def square = i * i   }   implicit def richInt(i: Int) = new RichInt(i) }