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Class Inheritance

Class inheritance is a mechanism where you can derive a class from another class for a hierarchy of classes that share a set of attributes and methods

To inherit from a class, use the extends keyword:

# Animal.gd
extends Node2D # Inherits from the Global Node2D class

class_name Animal

# Horse.gd
extends Animal # Inherits from the Global Node2D class

class_name Horse

graph TB; Animal.gd-->|Horse Inherits from Animal|Horse.gd;

In this case, the Animal class is called a superclass, while the Horse class is called the subclass.

When a subclass inherits from a superclass, the subclass gets all the functions and class variables of the superclass.

# Animal.gd
extends Node2D # Inherits from the Global Node2D class

class_name Animal

var health: int = 100

func getHealth() -> int:
    return health

# Horse.gd
extends Animal 

# Horse class has the health variable and the getHealth() method

class_name Horse

func newlyCreatedFunction() -> void:
    print(getHealth()) # 100

# Animal.gd
extends Node2D # Inherits from the Global Node2D class

class_name Animal

var health: int = 100

func getHealth() -> int:
    return health

# Horse.gd
extends Animal 

# Horse class has the health variable and the getHealth() method

class_name Horse

func newlyCreatedFunction() -> void:
    print(getHealth()) # 100

Overriding a Superclass Function

You can override a superclass function by merely writing out the function in the subclass.

# Animal.gd
extends Node2D # Inherits from the Global Node2D class

class_name Animal

func attack() -> void:
    print("Animal Attacks")

# Horse.gd
extends Animal 

# Horse class has the health variable and the getHealth() method

class_name Horse

func attack() -> void:
    print("Horse Attacks") # Override function attack()