Studies about Dart mixins

mixin_basic_usage.dart

void main() {
  final b = Bird();

  print('$b is ${b.fly()}');
  print('$b is ${b.peck()}');
}

class Bird with Peck {
  String fly() => 'flying';
}

mixin Peck {
  String peck() => 'pecking';
}

/**
 * Output:

Instance of 'Bird' is flying
Instance of 'Bird' is pecking
Exited

 */

multiple_mixins.dart

void main() {
  final p = Parrot();
  print('$p is ${p.fly()}');
  print('$p is ${p.peck()}');
  print('$p is ${p.talk()}');
}

class Bird {
  String fly() => 'flying';
}

/// Multiple mixins example.
/// Functions on 'Talk' and 'Peck' can be used by Parrot instances
class Parrot extends Bird with Talk, Peck {}

mixin Talk {
  String talk() => 'talking';
}

/// This mixin can only be added on Bird subclasses
mixin Peck on Bird {
  String peck() => 'pecking';
}

/**
 * Output:

Instance of 'Parrot' is flying
Instance of 'Parrot' is pecking
Instance of 'Parrot' is talking
Exited

 */

specific_class_mixins.dart

void main() {
  final p = Parrot();
  print('$p is ${p.fly()}');
  print('$p is ${p.talk()}');
  print('$p is ${p.findFood()}');

  final w = Woodpecker();
  print('$w is ${w.fly()}');
  print('$w is ${w.peck()}');

  final person = Person();
  print('$person is ${person.walk()}');
  print('$person is ${person.talk()}');
}

abstract class Bird {
  String fly() => 'flying';
  String findFood() => 'finds food';
}

class Parrot extends Bird with Talk {}

class Woodpecker extends Bird with Peck {}

class Person with Talk {
  String walk() => 'walking';
}

/// Used by Parrot and Person
mixin Talk {
  String talk() => 'talking';
}

/// Used by Woodpecker, which is a Bird
mixin Peck on Bird {
  /// As Bird class has 'findFood()' method, we can call it here.
  String peck() {
    return 'pecking and ${findFood()}';
  }
}

/**
 * Output:

Instance of 'Parrot' is flying
Instance of 'Parrot' is talking
Instance of 'Parrot' is finds food
Instance of 'Woodpecker' is flying
Instance of 'Woodpecker' is pecking and finds food
Instance of 'Person' is walking
Instance of 'Person' is talking
Exited

 */