Arma Reforger:Scripting: Conventions

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Format reminder:
  • camelCase is writing by gluing words together and making their first letter capital, but for the first one, e.g namingLikeThis.
  • PascalCase is writing in camelCase but with the first letter set uppercase, e.g NamingLikeThis.
  • snake casing (naming_like_this) is not a convention used in Enfusion.
    Only const values should be NAMED_LIKE_THIS.


Tag

To prevent conflict with other scripts all classes, and global functions must be distinguished by a Tag.

Bohemia Interactive scripts have been prefixed with SCR_. A mod developer must choose their own tag and not use one already taken by Bohemia Interactive or another developer.

When modding any class, all methods and variables within that modded class must also be distinguished by the same unique tag to prevent conflict.


File/Class

  • File should be called TAG_MyObject.c
    • A component must end with "component": TAG_ExampleComponent.c
    • An entity must end with "entity': TAG_ExampleEntity.c
  • Class should be called the same (without file extension):
    • class TAG_MyObject
    • class TAG_ExampleComponent
    • class TAG_ExampleEntity
  • Enum:
    • name must be prefixed with a capital E, e.g TAG_EMyEnum
    • values use all capital letters with words separated by underscores, e.g TAG_EMyEnum.VALUE_1
  • The file should be located in the scripts\Game directory
  • The use of plural is prohibited at the end of combined keywords: e.g TAG_NotificationsComponentTAG_NotificationComponent


Method

  • Functions/Methods naming uses PascalCase, e.g:
    int ReturnNumber()
  • Parameters are named with camelCase, e.g:
    int ReturnNumber(bool canBeNegative)


Variable

See this page for more information.
  • Member variables are prefixed with m_, a one-letter type prefix for specific types (see Value types), and use PascalCase, e.g:
    Entity m_Entity; int m_iHealth; bool m_bIsEnemy;
  • Global variables are prefixed with g_.
    Global variables are bad practice and must not be used outside of absolute necessity!
  • Static variables are prefixed with s_ (constants are not), eventually a one-letter type prefix, and use PascalCase, e.g
    protected static int s_iUnitsCount;
  • Local variables and arguments (method parameters) use camelCase, e.g:
    void MethodA() { int value = 42; string name = "John"; float result = MethodB(value, name); }
  • Constant values use all capital letters with words separated by underscores (uppercase snake casing), e.g:
    const int MAX_VALUE = 9999; // no 'm_' prefix nor 'i' type prefix static const int TOTAL = 10; // no 's_' prefix either

Order

  • First go Attributes (if any),
  • then public, protected, private member variables
  • then public, protected, private static variables
  • then public, protected, private constants

[Attribute()] protected int m_iAttribute; int m_iPublic; protected int m_iProtected; private int m_iPrivate; static int s_iPublic; protected static int s_iProtected; private static int s_iPrivate; static const int PUBLIC; protected static const int PROTECTED; private static const int PRIVATE;


Script

General

  • Curly braces must always be on a new line - Enforce Script uses Allman style
  • Variables and functions should be protected whenever possible (respecting OOP black box principle) unless they are intended to be exposed
  • Getters/Setters: variables should be made protected and accessed through getters and setters (entry methods getting/setting the value)

class SCR_HumanComponent : ScriptComponent { protected int m_iAge; void SetAge(int age) { m_iAge = age; PrintFormat("Age of instance %1 is now %2", this, m_iAge); } int GetAge() { return m_iAge; } }

Spacing

  • Tabs are used for indentation - they are set to a size of 4 spaces in Script Editor
  • A space is used before and after:
    • a binary operator
    • a foreach colon
    • a class' inheritance colon
  • A space is used after:
    • if, for, foreach, switch, while keywords
    • a for semicolon
  • Spaces are used inside parentheses but not around their content

class SCR_HumanComponent : ScriptComponent { if (true) { } for (int i = 0; i < 10; i++) { } foreach (string item : stringArray) { } switch (value) { case 42: break; } while (true) { } }

Method

  • All methods must be separated using this sequence of characters: two slashes followed by 96 dashes (see Example)
    //------------------------------------------------------------------------------------------------
  • Documentation must be done with Doxygen support in mind, using the //! comment syntax (see Example)
  • Methods should be sorted in the following order (top to bottom):
    • General methods
    • EOnFrame
    • EOnInit
    • Constructor
    • Destructor

//! A scripted entity class SCR_ScriptedEntity : GenericEntity { //------------------------------------------------------------------------------------------------ //! Get the normalized direction vector at position A pointing to B //! \param vectorA First position, direction origin //! \param vectorB Second position, direction goal //! \return The direction from A to B as a normalized vector protected vector GetNormalizedDirection(vector vectorA, vector vectorB) { vector dir = vectorB - vectorA; return dir.Normalized(); } //------------------------------------------------------------------------------------------------ //! Frame override void EOnFrame(IEntity owner, float timeSlice) { vector direction = GetNormalizedDirection(owner.GetOrigin(), vector.Zero); Print("OnFrame was called! Direction: " + direction); } //------------------------------------------------------------------------------------------------ //! Init override void EOnInit(IEntity owner) { Print("Init was called!"); } //------------------------------------------------------------------------------------------------ // constructor void SCR_ScriptedEntity(IEntitySource src, IEntity parent) { SetEventMask(EntityEvent.INIT | EntityEvent.FRAME | EntityEvent.CONTACT); } //------------------------------------------------------------------------------------------------ // destructor void ~SCR_ScriptedEntity() { Print("Destructing SCR_ScriptedEntity"); } }

Miscellaneous

  • class instanciation with the new keyword must use parentheses:
    SCR_Class myClass = new SCR_Class(); // correct SCR_Class myClass = new SCR_Class; // wrong
  • arrays can be initialised directly:
    array<string> myArray = {}; // correct array<string> myArray = new array<string>(); // tolerable array<string> myArray = new array<string>; // wrong


Moddability

It is important to keep moddability in mind when scripting to ensure. Modded classes work very similar to inherited ones and come with the same restrictions:

  • Constructor/Destructor: a modded class has its own const/destructor and cannot modify the parent one
  • Private variables & methods: a modded class cannot override parent's private members - use protected instead of private
  • Static variables & methods: same as above - do not use unless absolutely necessary
  • Global methods: no classes to mod - do not use unless absolutely necessary.


Example

[EntityEditorProps("GameScripted/SomeFolder", "Description of this component", "255 0 0 255", true, true, "", "box", "-0.25 -0.25 -0.25", "0.25 0.25 0.25", "0 0 0 0")] class SCR_SomeComponentClass { } SCR_SomeComponentClass SCR_SomeComponentSource; //! Flags used for an entity to define its currently active components. enum SomeFlags { MESH = 1, BODY = 2, HIERARCHY = 4, NET = 8, } //! A brief explanation of what this component does. //! The explanation can be spread across multiple lines. //! This should help with quickly understanding the script's purpose. class SCR_SomeComponent : ScriptComponent { //! Defines the maximum distance at which this object will be rendered in metres. [Attribute("30.0", UIWidgets.Slider, "The maximum distance at which this object will be rendered in metres.", "0 120 0.1")] protected float m_fRenderDistance; //! Maximum count of children that can be spawned at any time. If the limit is exceeded no more children are spawned. [Attribute("100", desc: "Maximum count of children that can be spawned at any time. If the limit is exceeded no more children are spawned.", "0 500")] protected int m_iMaximumChildCount; //! The offset of this object in metres. protected vector m_vPositionOffset = "0 0 0"; //! A public variable float m_fSomethingPublic = 3.2; //! A public vector vector m_vOtherPublic = "1 2 3"; //! Defines the minimum distance (in metres) for this object to render. If below this value, object will be culled. const float RENDER_DISTANCE_MINIMUM = 10; //! Defines the maximum distance (in metres) for this object to render. If above this value, object will be culled. const float RENDER_DISTANCE_MAXIMUM = 100; //------------------------------------------------------------------------------------------------ //! Returns the render distance of this object (metres). float GetRenderDistance() { return m_fRenderDistance; } //------------------------------------------------------------------------------------------------ //! Set the render distance of this object. //! \param renderDistance distance in metres. Is clamped between RENDER_DISTANCE_MINIMUM and RENDER_DISTANCE_MAXIMUM. void SetRenderDistance(float renderDistance) { m_fRenderDistance = Math.Clamp(renderDistance, RENDER_DISTANCE_MINIMUM, RENDER_DISTANCE_MAXIMUM); } //------------------------------------------------------------------------------------------------ //! Prints hello to the debug console. Protected method, not exposed to outside classes but available to child classes. protected void SayHello() { string localString = "Hello!"; Print(localString); } //------------------------------------------------------------------------------------------------ //! Compare two integers, return the larger one. (Don't mind the silly documentation, mind the syntax) //! \param a first parameter to be compared with the second one //! \param b second parameter to be compared with the first one //! \return true if a is equal to b, false otherwise. bool AreEqual(int a, int b) { // can be simplified to "return a == b;" if (a == b) return true; else return false; } //------------------------------------------------------------------------------------------------ override void EOnInit(IEntity owner) { Print("Initialized some component!"); } //------------------------------------------------------------------------------------------------ // constructor - remove if empty void SCR_SomeComponent(IEntityComponentSource src, IEntity ent, IEntity parent) { ent.SetEventMask(EntityEvent.INIT); // If offset is 0, no need to update if (m_vPositionOffset != "0 0 0") { // Get current transformation matrix, add the position offset and update transformation. vector mat[4]; ent.GetTransform(mat); mat[3] = mat[3] + m_vPositionOffset; ent.SetTransform(mat); } } //------------------------------------------------------------------------------------------------ // destructor - remove if left empty void ~SCR_SomeComponent() { } }