Examples in various object-oriented programming languages about how structural typing is supported. Solutions with languages that do not support structural typing are also detailed with a workaround solution (e.g., using an adapter).

Contributions (pull requests) are welcome.

Contribute

Contributions with languages having some support of structural typing are preferred. The examples must use explicit structural typing features provided by the language (e.g., a Java solution using reflexivity will not be accepted).

Please follow this format (take a look at the existing solutions):

• a folder with the name of the programming language;
• an executable script file named run that compiles and executes the program on Linux;
• a README file that explains how the language supports structural typing (or not, and in this case explanations about the workaround are expected);
• The code that follows the scenario.

Scenario

A type Duck exists with two functions quack and dance that return a string object.

A type Wolf exists with three functions: quack, dance, and eat. The functions quack and dance have the same prototype than in Duck and respectively return: "QUACK QUACK WHOO" and " ¯\_()_/¯ ". The function eat takes a Duck instance as parameter and returns the string: " 😈 ". Wolf must not be defined as a Duck (i.e., no nominal typing).

A type Mallard (implicitly or explicitly) implements the Duck type: quack returns "quack quack" and dance returns " _/¯ ".

The program creates a Wolf called wolf, then declares a Duck called theDuck. The wolf then takes the form of a Duck through theDuck. A Mallard called aDuck is then created.

In a dedicated method called twoDucksAlone that takes as arguments two ducks d1 and d2 :

d1 and d2 quack.

d1 and d2 dance.

After this method call with aDuck and theDuck as parameters:

wolf eats aDuck.

The output of the program should be:

quack quack
QUACK QUACK WHOO
 _/¯ 
 ¯\_()_/¯ 
 😈