Dan Rosen

``` class Foo { val a = 1; val b = a + 1; } class Bar extends Foo { val a = 100; } ```

util, finagle, scalding, algebird, ...

More text when introducing `val` on why immutability is a good thing.

Should be simple, see [CodeMirror manual](http://codemirror.net/doc/manual.html#keymaps).

Interpreter sandbox

1

Users shouldn't be allowed to troll like: ``` scala System.exit(0) ``` or ``` scala while (true) println("LOL") ``` or ``` scala val f = new File("/") f.delete() ``` I think...