Our coding style

This document explains some choices we made in our coding style.

Mainly:

• Why some variable names have a leading underscore.
• Why we use type hints.

We follow many more rules and conventions to keep our code consistent and hopefully easy to read.

You can find all our code guidelines here: GDQuest GDScript guidelines.

Variable names with a leading underscore

Many of our property names have a leading underscore.

This is a convention we borrowed from Python: as GDScript doesn’t have private variables, we use a leading underscore to tell our teammates they’re pseudo-private.

In other words, a variable with a leading underscore means it’s not intended for use outside this class.

Some examples of variable names:

# We expose the speed for both read and write access.
var speed := 500.0

# The velocity is for use inside this class only.
var _velocity := Vector2.ZERO

# We store a reference to a child node, but only this script uses this
# reference.
onready var _enemy_detector: Area2D = $EnemyDetector

Technically, in GDScript, as in Python, you can always access all variables. In Godot, you can get a reference to any node inside your scene tree.

This can cause more harm than good as it gives you a lot of room to do things that’ll backfire, like accessing nodes in unintuitive ways.

At GDQuest, we use conventions like the leading underscore to limit problems, along with many other coding guidelines.

Type hints

GDScript is a gradually-typed language, meaning you’re free to write fully dynamic code or to specify types for your variables and functions.

We use types as much as possible. For example, instead of func _process(delta):, we use func _process(delta: float) -> void:.

The colon after the delta argument specifies the variable’s type, while the arrow tells Godot the function’s return type: here, nothing.

When defining a new variable, the GDScript compiler can often infer the variable’s type if you write :=.

Why bother? There are large benefits to using types:

• The compiler will catch many errors as you type the code. It can’t catch most of those without type hints.
• You get much better autocompletion in most situations.
• Your code contains more information for you and your teammates, helping everyone understand it better.
• From Godot 4, using types leads to better performance than dynamic code, up to twice as fast.

All that for a little more typing.

Note that there’s a handy editor setting to have Godot autocomplete type hints whenever possible. To get that:

1. Head to the Editor -> Editor Settings…
2. In the search bar, enter “type hints”
3. In the Completion section, turn on the checkbox next to Add Type Hints.

You can learn more about optional typing and its benefits in our guide to using type hints in GDScript.