## Dart ##
**Length 6:**

    a as B

The `as` keyword allows you to cast an object to any type, in this case the variable `a` is cast to type `B`. This is very useful when you know the type of an object returned by a dynamic method and want the tooling to reflect that. For instance, if you were working with HTML and queried the DOM for an element, you could specify the type of the element, even though that type is not actually returned:

<!-- language: lang-dart -->

    InputElement input = querySelector('#someInput') as InputElement;
    // Go ahead and use input safely as an InputElement

**Length 5:**

    'A$k'

`$` is used within Strings for interpolation. In this example if `k` was a variable with a value of `wkward`, the full value of the interpolated String would be `Awkward`.

**Length 4:**

    true

Unlike other languages such as JavaScript, in Dart `true` is the only value that is `true`. The same applies to `false`. Values such as `0`, `1`, `''`, `null` are not truthy.

**Length 3:**

    var

Var allows a variable to refer to any type of object. Tools will attempt to infer the actual type of the object.

**Length 2:**

    {}

Dart supports map literals.

**Length 1:**

    ;

Semi-colons are mandatory to terminate a statement.

**Factoid:** Dart is an [optionally typed](https://www.dartlang.org/articles/optional-types/) language, which means you can add types to aid developers and tools, but they have no effect on your program's semantics - it will run the same whether you add types, or don't, or even add incorrect types.