Methods

A function declared inside a class is a method: something the objects of the class can do. Like any function, a method can take parameters and return a value, and it can read and change the object's variables:

# score_board.gd
class_name ScoreBoard
extends RefCounted

var points: int = 0

func greet() -> void:
	print("Scoreboard ready")

func add(amount: int) -> void:
	points += amount

func doubled() -> int:
	return points * 2

func add_bonus() -> int:
	add(10)
	return points

Call a method on an object with a dot and pass the arguments in the parentheses:

var board := ScoreBoard.new()
board.greet() # Scoreboard ready
board.add(5)
print(board.doubled()) # 10
print(board.add_bonus()) # 15

Inside the class, a method calls another method of the same object by its name: add(10) in add_bonus() means self.add(10).

A method declared with -> void returns nothing, and one declared with -> int must return an int. Each call works on its own object: board.add(5) changes board.points and no other scoreboard.

The call must match the declaration: board.add() without an argument is an error reported before the program runs.