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);
    }
  }
}