A Scala 2.10 (and newer) implicit class example (how to add new functionality to closed classes)

Scala FAQ: Can you share an example of how to create an implicit class in Scala 2.10?

Sure. As the question implies, the implicit class functionality changed in Scala 2.10, so let's take a look at the new syntax.


Rather than create a separate library of String utility methods, like a StringUtilities class, you want to add your own behavior(s) to the String class, so you can write code like this:

A Scala implicit method argument and field example

UPDATE: This example shows how to create an implicit method in Scala 2.9 or older. You can use a slightly simpler approach with Scala 2.10 and newer, which I've documented in this Scala 2.10 implicit class example.

I'm not going to do much writing here today, but instead I'll just demonstrate how an implicit method argument works with implicit fields in Scala. Without any further ado, here's some code:

Scala REPL: How to show more methods on a class/object in the REPL

When you're working in the Scala REPL and want to see what methods are available on a class/object, you can create an instance of an object, follow that with the "." character, and then press the [Tab] key. This process, known as "tab completion" in the REPL, gives you a preliminary list of methods that can be called on the object.

Here's what this looks like when we try it on an Int object: