GDScript style guide

This style guide lists conventions to write elegant GDScript. The goal is to encourage writing clean, readable code and promote consistency across projects, discussions, and tutorials. Hopefully, this will also support the development of auto-formatting tools.

Since GDScript is close to Python, this guide is inspired by Python’s PEP 8 programming style guide.

Style guides aren’t meant as hard rulebooks. At times, you may not be able to apply some of the guidelines below. When that happens, use your best judgment, and ask fellow developers for insights.

In general, keeping your code consistent in your projects and within your team is more important than following this guide to a tee.

Note

Godot’s built-in script editor uses a lot of these conventions by default. Let it help you.

Here is a complete class example based on these guidelines:

  1. class_name StateMachine
  2. extends Node
  3. # Hierarchical State machine for the player.
  4. # Initializes states and delegates engine callbacks
  5. # (_physics_process, _unhandled_input) to the state.
  8. signal state_changed(previous, new)
  10. export var initial_state = NodePath()
  11. var is_active = true setget set_is_active
  13. onready var _state = get_node(initial_state) setget set_state
  14. onready var _state_name = _state.name
  17. func _init():
  18.     add_to_group("state_machine")
  21. func _ready():
  22.     connect("state_changed", self, "_on_state_changed")
  23.     _state.enter()
  26. func _unhandled_input(event):
  27.     _state.unhandled_input(event)
  30. func _physics_process(delta):
  31.     _state.physics_process(delta)
  34. func transition_to(target_state_path, msg={}):
  35.     if not has_node(target_state_path):
  36.         return
  38.     var target_state = get_node(target_state_path)
  39.     assert(target_state.is_composite == false)
  41.     _state.exit()
  42.     self._state = target_state
  43.     _state.enter(msg)
  44.     Events.emit_signal("player_state_changed", _state.name)
  47. func set_is_active(value):
  48.     is_active = value
  49.     set_physics_process(value)
  50.     set_process_unhandled_input(value)
  51.     set_block_signals(not value)
  54. func set_state(value):
  55.     _state = value
  56.     _state_name = _state.name
  59. func _on_state_changed(previous, new):
  60.     print("state changed")
  61.     emit_signal("state_changed")

Formatting

Encoding and special characters

  • Use line feed (LF) characters to break lines, not CRLF or CR. (editor default)

  • Use one line feed character at the end of each file. (editor default)

  • Use UTF-8 encoding without a byte order mark. (editor default)

  • Use Tabs instead of spaces for indentation. (editor default)

Indentation

Each indent level should be one greater than the block containing it.

Good:

  1. for i in range(10):
  2.     print("hello")

Bad:

  1. for i in range(10):
  2.   print("hello")
  4. for i in range(10):
  5.         print("hello")

Use 2 indent levels to distinguish continuation lines from regular code blocks.

Good:

  1. effect.interpolate_property(sprite, "transform/scale",
  2.             sprite.get_scale(), Vector2(2.0, 2.0), 0.3,
  3.             Tween.TRANS_QUAD, Tween.EASE_OUT)

Bad:

  1. effect.interpolate_property(sprite, "transform/scale",
  2.     sprite.get_scale(), Vector2(2.0, 2.0), 0.3,
  3.     Tween.TRANS_QUAD, Tween.EASE_OUT)

Exceptions to this rule are arrays, dictionaries, and enums. Use a single indentation level to distinguish continuation lines:

Good:

  1. var party = [
  2.     "Godot",
  3.     "Godette",
  4.     "Steve",
  5. ]
  7. var character_dir = {
  8.     "Name": "Bob",
  9.     "Age": 27,
  10.     "Job": "Mechanic",
  11. }
  13. enum Tiles {
  14.     TILE_BRICK,
  15.     TILE_FLOOR,
  16.     TILE_SPIKE,
  17.     TILE_TELEPORT,
  18. }

Bad:

  1. var party = [
  2.         "Godot",
  3.         "Godette",
  4.         "Steve",
  5. ]
  7. var character_dir = {
  8.         "Name": "Bob",
  9.         "Age": 27,
  10.         "Job": "Mechanic",
  11. }
  13. enum Tiles {
  14.         TILE_BRICK,
  15.         TILE_FLOOR,
  16.         TILE_SPIKE,
  17.         TILE_TELEPORT,
  18. }

Trailing comma

Use a trailing comma on the last line in arrays, dictionaries, and enums. This results in easier refactoring and better diffs in version control as the last line doesn’t need to be modified when adding new elements.

Good:

  1. enum Tiles {
  2.     TILE_BRICK,
  3.     TILE_FLOOR,
  4.     TILE_SPIKE,
  5.     TILE_TELEPORT,
  6. }

Bad:

  1. enum Tiles {
  2.     TILE_BRICK,
  3.     TILE_FLOOR,
  4.     TILE_SPIKE,
  5.     TILE_TELEPORT
  6. }

Trailing commas are unnecessary in single-line lists, so don’t add them in this case.

Good:

  1. enum Tiles {TILE_BRICK, TILE_FLOOR, TILE_SPIKE, TILE_TELEPORT}

Bad:

  1. enum Tiles {TILE_BRICK, TILE_FLOOR, TILE_SPIKE, TILE_TELEPORT,}

Blank lines

Surround functions and class definitions with two blank lines:

  1. func heal(amount):
  2.     health += amount
  3.     health = min(health, max_health)
  4.     emit_signal("health_changed", health)
  7. func take_damage(amount, effect=null):
  8.     health -= amount
  9.     health = max(0, health)
  10.     emit_signal("health_changed", health)

Use one blank line inside functions to separate logical sections.

Line length

Keep individual lines of code under 100 characters.

If you can, try to keep lines under 80 characters. This helps to read the code on small displays and with two scripts opened side-by-side in an external text editor. For example, when looking at a differential revision.

One statement per line

Never combine multiple statements on a single line. No, C programmers, not even with a single line conditional statement.

Good:

  1. if position.x > width:
  2.     position.x = 0
  4. if flag:
  5.     print("flagged")

Bad:

  1. if position.x > width: position.x = 0
  3. if flag: print("flagged")

The only exception to that rule is the ternary operator:

  1. next_state = "fall" if not is_on_floor() else "idle"

Avoid unnecessary parentheses

Avoid parentheses in expressions and conditional statements. Unless necessary for order of operations, they only reduce readability.

Good:

  1. if is_colliding():
  2.     queue_free()

Bad:

  1. if (is_colliding()):
  2.     queue_free()

Boolean operators

Prefer the plain English versions of boolean operators, as they are the most accessible:

  • Use and instead of &&.

  • Use or instead of ||.

You may also use parentheses around boolean operators to clear any ambiguity. This can make long expressions easier to read.

Good:

  1. if (foo and bar) or baz:
  2.     print("condition is true")

Bad:

  1. if foo && bar || baz:
  2.     print("condition is true")

Comment spacing

Regular comments should start with a space, but not code that you comment out. This helps differentiate text comments from disabled code.

Good:

  1. # This is a comment.
  2. #print("This is disabled code")

Bad:

  1. #This is a comment.
  2. # print("This is disabled code")

Note

In the script editor, to toggle the selected code commented, press Ctrl + K. This feature adds a single # sign at the start of the selected lines.

Whitespace

Always use one space around operators and after commas. Also, avoid extra spaces in dictionary references and function calls.

Good:

  1. position.x = 5
  2. position.y = target_position.y + 10
  3. dict["key"] = 5
  4. my_array = [4, 5, 6]
  5. print("foo")

Bad:

  1. position.x=5
  2. position.y = mpos.y+10
  3. dict ["key"] = 5
  4. myarray = [4,5,6]
  5. print ("foo")

Don’t use spaces to align expressions vertically:

  1. x        = 100
  2. y        = 100
  3. velocity = 500

Quotes

Use double quotes unless single quotes make it possible to escape fewer characters in a given string. See the examples below:

  1. # Normal string.
  2. print("hello world")
  4. # Use double quotes as usual to avoid escapes.
  5. print("hello 'world'")
  7. # Use single quotes as an exception to the rule to avoid escapes.
  8. print('hello "world"')
  10. # Both quote styles would require 2 escapes; prefer double quotes if it's a tie.
  11. print("'hello' \"world\"")

Numbers

Don’t omit the leading or trailing zero in floating-point numbers. Otherwise, this makes them less readable and harder to distinguish from integers at a glance.

Good:

  1. var float_number = 0.234
  2. var other_float_number = 13.0

Bad:

  1. var float_number = .234
  2. var other_float_number = 13.

Use lowercase for letters in hexadecimal numbers, as their lower height makes the number easier to read.

Good:

  1. var hex_number = 0xfb8c0b

Bad:

  1. var hex_number = 0xFB8C0B

Take advantage of GDScript’s underscores in literals to make large numbers more readable.

Good:

  1. var large_number = 1_234_567_890
  2. var large_hex_number = 0xffff_f8f8_0000
  3. var large_bin_number = 0b1101_0010_1010
  4. # Numbers lower than 1000000 generally don't need separators.
  5. var small_number = 12345

Bad:

  1. var large_number = 1234567890
  2. var large_hex_number = 0xfffff8f80000
  3. var large_bin_number = 0b110100101010
  4. # Numbers lower than 1000000 generally don't need separators.
  5. var small_number = 12_345

Naming conventions

These naming conventions follow the Godot Engine style. Breaking these will make your code clash with the built-in naming conventions, leading to inconsistent code.

File names

Use snake_case for file names. For named classes, convert the PascalCase class name to snake_case:

  1. # This file should be saved as `weapon.gd`.
  2. extends Node
  3. class_name Weapon
  1. # This file should be saved as `yaml_parser.gd`.
  2. extends Object
  3. class_name YAMLParser

This is consistent with how C++ files are named in Godot’s source code. This also avoids case sensitivity issues that can crop up when exporting a project from Windows to other platforms.

Classes and nodes

Use PascalCase for class and node names:

  1. extends KinematicBody

Also use PascalCase when loading a class into a constant or a variable:

  1. const Weapon = preload("res://weapon.gd")

Functions and variables

Use snake_case to name functions and variables:

  1. var particle_effect
  2. func load_level():

Prepend a single underscore (_) to virtual methods functions the user must override, private functions, and private variables:

  1. var _counter = 0
  2. func _recalculate_path():

Signals

Use the past tense to name signals:

  1. signal door_opened
  2. signal score_changed

Constants and enums

Write constants with CONSTANT_CASE, that is to say in all caps with an underscore (_) to separate words:

  1. const MAX_SPEED = 200

Use PascalCase for enum names and CONSTANT_CASE for their members, as they are constants:

  1. enum Element {
  2.     EARTH,
  3.     WATER,
  4.     AIR,
  5.     FIRE,
  6. }

Code order

This first section focuses on code order. For formatting, see Formatting. For naming conventions, see Naming conventions.

We suggest to organize GDScript code this way:

  1. 01. tool
  2. 02. class_name
  3. 03. extends
  4. 04. # docstring
  6. 05. signals
  7. 06. enums
  8. 07. constants
  9. 08. exported variables
  10. 09. public variables
  11. 10. private variables
  12. 11. onready variables
  14. 12. optional built-in virtual _init method
  15. 13. built-in virtual _ready method
  16. 14. remaining built-in virtual methods
  17. 15. public methods
  18. 16. private methods

We optimized the order to make it easy to read the code from top to bottom, to help developers reading the code for the first time understand how it works, and to avoid errors linked to the order of variable declarations.

This code order follows four rules of thumb:

  1. Properties and signals come first, followed by methods.

  2. Public comes before private.

  3. Virtual callbacks come before the class’s interface.

  4. The object’s construction and initialization functions, _init and _ready, come before functions that modify the object at runtime.

Class declaration

If the code is meant to run in the editor, place the tool keyword on the first line of the script.

Follow with the class_name if necessary. You can turn a GDScript file into a global type in your project using this feature. For more information, see GDScript basics.

Then, add the extends keyword if the class extends a built-in type.

Following that, you should have the class’s optional docstring as comments. You can use that to explain the role of your class to your teammates, how it works, and how other developers should use it, for example.

  1. class_name MyNode
  2. extends Node
  3. # A brief description of the class's role and functionality.
  4. # Longer description.

Signals and properties

Write signal declarations, followed by properties, that is to say, member variables, after the docstring.

Enums should come after signals, as you can use them as export hints for other properties.

Then, write constants, exported variables, public, private, and onready variables, in that order.

  1. signal spawn_player(position)
  3. enum Jobs {KNIGHT, WIZARD, ROGUE, HEALER, SHAMAN}
  5. const MAX_LIVES = 3
  7. export(Jobs) var job = Jobs.KNIGHT
  8. export var max_health = 50
  9. export var attack = 5
  11. var health = max_health setget set_health
  13. var _speed = 300.0
  15. onready var sword = get_node("Sword")
  16. onready var gun = get_node("Gun")

Note

The GDScript compiler evaluates onready variables right before the _ready callback. You can use that to cache node dependencies, that is to say, to get child nodes in the scene that your class relies on. This is what the example above shows.

Member variables

Don’t declare member variables if they are only used locally in a method, as it makes the code more difficult to follow. Instead, declare them as local variables in the method’s body.

Local variables

Declare local variables as close as possible to their first use. This makes it easier to follow the code, without having to scroll too much to find where the variable was declared.

Methods and static functions

After the class’s properties come the methods.

Start with the _init() callback method, that the engine will call upon creating the object in memory. Follow with the _ready() callback, that Godot calls when it adds a node to the scene tree.

These functions should come first because they show how the object is initialized.

Other built-in virtual callbacks, like _unhandled_input() and _physics_process, should come next. These control the object’s main loop and interactions with the game engine.

The rest of the class’s interface, public and private methods, come after that, in that order.

  1. func _init():
  2.     add_to_group("state_machine")
  5. func _ready():
  6.     connect("state_changed", self, "_on_state_changed")
  7.     _state.enter()
  10. func _unhandled_input(event):
  11.     _state.unhandled_input(event)
  14. func transition_to(target_state_path, msg={}):
  15.     if not has_node(target_state_path):
  16.         return
  18.     var target_state = get_node(target_state_path)
  19.     assert(target_state.is_composite == false)
  21.     _state.exit()
  22.     self._state = target_state
  23.     _state.enter(msg)
  24.     Events.emit_signal("player_state_changed", _state.name)
  27. func _on_state_changed(previous, new):
  28.     print("state changed")
  29.     emit_signal("state_changed")

Static typing

Since Godot 3.1, GDScript supports optional static typing.

Declared types

To declare a variable’s type, use <variable>: <type>:

  1. var health: int = 0

To declare the return type of a function, use -> <type>:

  1. func heal(amount: int) -> void:

Inferred types

In most cases you can let the compiler infer the type, using :=:

  1. var health := 0  # The compiler will use the int type.

However, in a few cases when context is missing, the compiler falls back to the function’s return type. For example, get_node() cannot infer a type unless the scene or file of the node is loaded in memory. In this case, you should set the type explicitly.

Good:

  1. onready var health_bar: ProgressBar = get_node("UI/LifeBar")

Bad:

  1. # The compiler can't infer the exact type and will use Node
  2. # instead of ProgressBar.
  3. onready var health_bar := get_node("UI/LifeBar")