## Comments

    // Single line comment
    /// Documentation single line comment
    /* Block comment
    on several lines */
    /** Multi-line
    doc comment */

## Annotations

    @todo('seth', 'make this do something')
    @deprecated // Metadata; makes Dart Editor warn about using activate().

## Numbers

    var x = 1;
    var hex = 0xDEADBEEF;
    var bigInt = 346534658346524376592384765923749587398457294759347029438709349347;
    var y = 1.1;
    var exponents = 1.42e5;

## Strings

    var s1 = 'Single quotes work well for string literals.';
    var s2 = "Double quotes work just as well.";
    var s3 = 'It\'s easy to escape the string delimiter.';
    var s4 = "It's even easier to just use the other string delimiter.";
    var s1 = '''
    You can create
    multi-line strings like this one.
    ''';
    var s2 = """This is also a
    multi-line string.""";
    var s = r"In a raw string, even \n isn't special.";

## Full example

    class Logger {
      final String name;
      bool mute = false;

      // _cache is library-private, thanks to the _ in front of its name.
      static final Map<String, Logger> _cache = <String, Logger>{};

      factory Logger(String name) {
        if (_cache.containsKey(name)) {
          return _cache[name];
        } else {
          final logger = new Logger._internal(name);
          _cache[name] = logger;
          return logger;
        }
      }

      Logger._internal(this.name);

      void log(String msg) {
        if (!mute) {
          print(msg);
        }
      }
    }