basic class w/named ctor

main.dart

//dart does not do interfaces, but rather all classes
//seem to be able to be implemented
abstract class IsFerocious {
  void intimidate();
  String whatTheFearfulSay();
}

class Animal{
  String  name;
  String lastName;
  String color;
  int weight;
  Animal(){}
  Animal.create(this.name){}
  Animal.fromInfo(this.name, this.lastName, this.color, this.weight){}
  
  String sayHello(){
    return 'grunt';
  }
  
}

class Cat extends Animal implements IsFerocious{
  Cat.create(String name): super.create(name){
   print(".create ctor used"); 
  }
  Cat.fromInfo(String name, String lastName, String color, int weight) : super.fromInfo(name, lastName, color, weight);
  
  @override
  String sayHello() {
    return 'meow';
  }
  
  @override
  void intimidate(){
    print("${this.name} hisses");
  }
  
  @override
  String whatTheFearfulSay(){
    print("oh no! the cat is hissing. I'm so scared");
  }
}
void main(){
  
  var name = "willis";
  var lastName = "busterino";
  
  String  yourAge(String name, String last, [int age]){
    var res = "$name $last";
    if (age != null){
      res += " is $age";
    }
    return res;
  }
  
  print(yourAge(name, lastName, 47));
  print(yourAge(name, lastName));
  
  var willie = new Cat.fromInfo(name, lastName, "black", 5);
  print("${willie.name} says ${willie.sayHello()}");
  
  var jeo = new Cat.create("jeordie");
  print("${jeo.name} says ${jeo.sayHello()}");
	willie.intimidate();
  willie.whatTheFearfulSay();
}