Type Inference

Part of the Fundamentals section of Coddy's GDScript journey. Lesson 11 of 92.

When the value already shows the type, writing the type again is repetitive. With :=, GDScript infers the type from the value:

var hp := 10 # int
var speed := 2.5 # float
var player_name := "Ada" # String
var is_alive := true # bool

The type is fixed when the variable is created. var hp := 10 means the same as var hp: int = 10, so a value of another type is an error:

var hp := 10
hp = 25 # OK: a new int
hp = "ten" # Error: hp is an int

Compare it with plain =: after var hp = 10, the variable has no fixed type, and hp = "ten" is allowed.

The type comes from the value, so := needs a value that has a type. var target := null is an error, because null does not say which type the variable should have. Write the type yourself in that case.

Challenge

Beginner

Create these variables with :=, so their types are inferred from the values:

quantity with the value 10
price with the value 99.99
message with the value "Coddy is awesome!"
is_available with the value true

Do not change the print() lines. The program prints:

Quantity: 10
Price: 99.99
Message: Coddy is awesome!
Is available: true

Try it yourself

extends Node

func _ready():
	# Create the variables below
	
	# Don't change the lines below
	print("Quantity: ", quantity)
	print("Price: ", price)
	print("Message: ", message)
	print("Is available: ", is_available)