Arma Reforger:ScriptInvoker Usage - Revision history

Lou Montana: Fix example, thanks Zelik/SweetPotatoh on Discord

2026-02-23T19:35:24Z

Fix example, thanks Zelik/SweetPotatoh on Discord

← Older revision		Revision as of 21:35, 23 February 2026
Line 117:		Line 117:
	class TAG_Subscriber		class TAG_Subscriber
	{		{
	protected TAG_EventHolder m_EventHolder;		protected ref TAG_EventHolder m_EventHolder;

	protected void WarnOfScoreChange(int newScore) // note the similarity with ScriptInvokerIntMethod's signature		protected void WarnOfScoreChange(int newScore) // note the similarity with ScriptInvokerIntMethod's signature
Line 129:		Line 129:
	UnSubscribe();		UnSubscribe();

	eventHolder.Insert(WarnOfScoreChange); // if the method signature were not matching, the compiler would warn here		eventHolder.GetOnScoreChanged().Insert(WarnOfScoreChange); // if the method signature were not matching, the compiler would warn here
	m_EventHolder = eventHolder;		m_EventHolder = eventHolder;
	}		}
Line 138:		Line 138:
	return;		return;

	m_EventHolder.Remove(WarnOfScoreChange);		m_EventHolder.GetOnScoreChanged().Remove(WarnOfScoreChange);
	m_EventHolder = null;		m_EventHolder = null;
	}		}

Lou Montana: Text replacement - "\{\{GameCategory\|armaR\|Modding\|(Guidelines|Tutorials)\|([^=↵]*)\}\}" to "{{GameCategory|armaR|Modding|$2|$1}}"

2025-02-26T12:32:01Z

Text replacement - "\{\{GameCategory\|armaR\|Modding\|(Guidelines|Tutorials)\|([^=↵]*)\}\}" to "{{GameCategory|armaR|Modding|$2|$1}}"

← Older revision		Revision as of 14:32, 26 February 2025
Line 153:		Line 153:


	{{GameCategory\|armaR\|Modding\|Tutorials~~\|Scripting~~}}		{{GameCategory\|armaR\|Modding\|Scripting\|Tutorials}}

Lou Montana: Fix example

2023-12-14T16:14:43Z

Fix example

← Older revision		Revision as of 18:14, 14 December 2023
Line 12:		Line 12:

	<spoiler text="Show example">		<spoiler text="Show example">
	<enforce>		<enforce methods="OnDogBark">
	class TAG_Dog		class TAG_Dog
	{		{
	protected ref ScriptInvokerVoid m_OnBark; // initialised on request - this allows saving RAM as ScriptInvokers are not small objects		protected ref ScriptInvokerVoid m_OnBark; // initialised on request - this allows saving RAM as ScriptInvokers are not small objects
	// IN GENERAL, do NOT expose the ScriptInvoker variable directly (as anyone could delete it)		// IN GENERAL, do NOT expose the ScriptInvoker variable directly (as anyone could delete it)
	// ~~Arma Reforger~~ code keeps Component events public for performance reason		// {{armaR}} code keeps Component events public for performance reason

	//! This method provides the ScriptInvoker for outsiders to subscribe to it		//! This method provides the ScriptInvoker for outsiders to subscribe to it
Line 92:		Line 92:

	<spoiler text="Show full example">		<spoiler text="Show full example">
	<enforce>		<enforce methods="WarnOfScoreChange">
	class TAG_EventHolder		class TAG_EventHolder
	{		{
Line 126:		Line 126:
	void Subscribe(notnull TAG_EventHolder eventHolder)		void Subscribe(notnull TAG_EventHolder eventHolder)
	{		{
	~~if (!eventHolder)~~
	~~return;~~

	if (m_EventHolder)		if (m_EventHolder)
	UnSubscribe();		UnSubscribe();

Lou Montana: Fix typo

2023-07-04T00:58:28Z

Fix typo

← Older revision		Revision as of 02:58, 4 July 2023
Line 95:		Line 95:
	class TAG_EventHolder		class TAG_EventHolder
	{		{
	protected in m_iScore;		protected int m_iScore;
	protected ref ScriptInvokerInt m_OnScoreChanged; // still created on request		protected ref ScriptInvokerInt m_OnScoreChanged; // still created on request

Lou Montana: Change ScriptInvoker → ScriptInvokerVoid preemptively + warning

2023-06-19T17:03:55Z

Change ScriptInvoker → ScriptInvokerVoid preemptively + warning

← Older revision		Revision as of 19:03, 19 June 2023
Line 8:		Line 8:

	== Usage ==		== Usage ==

			{{Feature\|warning\|Using the {{Link/Enfusion\|armaR\|ScriptInvoker}} class directly is considered bad practice and should be avoided!}}

	<spoiler text="Show example">		<spoiler text="Show example">
Line 13:		Line 15:
	class TAG_Dog		class TAG_Dog
	{		{
	protected ref ~~ScriptInvoker~~ m_OnBark; // initialised on request - this allows saving RAM as ScriptInvokers are not small objects		protected ref ScriptInvokerVoid m_OnBark; // initialised on request - this allows saving RAM as ScriptInvokers are not small objects
	// IN GENERAL, do NOT expose the ScriptInvoker variable directly (as anyone could delete it)		// IN GENERAL, do NOT expose the ScriptInvoker variable directly (as anyone could delete it)
			// Arma Reforger code keeps Component events public for performance reason

	//! This method provides the ScriptInvoker for outsiders to subscribe to it		//! This method provides the ScriptInvoker for outsiders to subscribe to it
	~~ScriptInvoker~~ GetOnBark()		ScriptInvokerVoid GetOnBark()
	{		{
	if (!m_OnBark)		if (!m_OnBark)
	m_OnBark = new ~~ScriptInvoker~~(); // the invoker is only created on external request		m_OnBark = new ScriptInvokerVoid(); // the invoker is only created on external request

	return m_OnBark;		return m_OnBark;
Line 73:		Line 76:
	== Signature Declaration ==		== Signature Declaration ==

	The <enforce inline>~~ScriptInvoker~~</enforce> class used above is the "default" one used for methods without arguments.		The <enforce inline>ScriptInvokerVoid</enforce> class used above is the "default" one used for methods without arguments.
	In order to provide arguments to the subscribed methods, a generic {{Link/Enfusion\|armaR\|ScriptInvokerBase}} type must be used, e.g <enforce inline>ScriptInvokerBase<func></enforce>.		In order to provide arguments to the subscribed methods, a generic {{Link/Enfusion\|armaR\|ScriptInvokerBase}} type must be used, e.g <enforce inline>ScriptInvokerBase<func></enforce>.

MarioE: Fixed the error with templates

2023-05-19T20:16:25Z

Fixed the error with templates

← Older revision		Revision as of 22:16, 19 May 2023
Line 74:		Line 74:

	The <enforce inline>ScriptInvoker</enforce> class used above is the "default" one used for methods without arguments.		The <enforce inline>ScriptInvoker</enforce> class used above is the "default" one used for methods without arguments.
	In order to provide arguments to the subscribed methods, a generic {{Link/Enfusion\|armaR\|ScriptInvokerBase}} type must be used, e.g <enforce inline>ScriptInvokerBase<~~TypeA, TypeB, TypeC~~></enforce>.		In order to provide arguments to the subscribed methods, a generic {{Link/Enfusion\|armaR\|ScriptInvokerBase}} type must be used, e.g <enforce inline>ScriptInvokerBase<func></enforce>.

	A method signature can be declared using {{hl\|typedef}}:		A method signature can be declared using {{hl\|typedef}}:

Lou Montana: Page creation

2023-05-19T18:00:13Z

Page creation

New page

{{Feature|informative|See {{Link|Arma Reforger:Event Handlers}} for {{Link/Enfusion|armaR|ScriptInvoker}} guidelines.}}

A {{Link/Enfusion|armaR|ScriptInvoker}} is an object that allows other objects to subscribe to the event it represents by registering a method.
Such event can provide arguments and it is important for the subscribing methods to fit the proper method signature.

The interest of using Events is that the subscribed method is be executed only ''if'' and ''when'' a specific event occurs (e.g a fired weapon, someone leaving a vehicle, etc) - no periodical check is done, saving CPU cycles and executing exactly on event.

== Usage ==

<spoiler text="Show example">
<enforce>
class TAG_Dog
{
protected ref ScriptInvoker m_OnBark; // initialised on request - this allows saving RAM as ScriptInvokers are not small objects
// IN GENERAL, do NOT expose the ScriptInvoker variable directly (as anyone could delete it)

//! This method provides the ScriptInvoker for outsiders to subscribe to it
ScriptInvoker GetOnBark()
{
if (!m_OnBark)
m_OnBark = new ScriptInvoker(); // the invoker is only created on external request

return m_OnBark;
}

void Bark()
{
if (m_OnBark) // the invoker can be null if nobody subscribed to it - no need to create it
m_OnBark.Invoke();

Print("Dog barked", LogLevel.DEBUG);
}
}

class TAG_Neighbour
{
protected TAG_Dog m_Dog; // no strong ref
protected int m_iBarkCount;

protected void OnDogBark()
{
if (m_iBarkCount < 1)
Print("The dog barked!", LogLevel.NORMAL);
else if (m_iBarkCount < 10)
Print("Oh, it barked again!", LogLevel.NORMAL);
else
Print("MAKE IT STOP", LogLevel.WARNING);

m_iBarkCount++;
}

//! Constructor
void TAG_Neighbour(notnull TAG_Dog dog)
{
m_Dog = dog;
m_Dog.GetOnBark().Insert(OnDogBark); // GetOnBark() creates the invoker
// Insert() adds OnDogBark to the list of methods to be called
}

//! Destructor
void ~TAG_Neighbour()
{
// do not forget to unsubscribe for good practice, clean code aaand to avoid potential memory leaks
if (m_Dog)
m_Dog.GetOnBark().Remove(OnDogBark); // removes OnDogBark from the list of methods to be called
}
}
</enforce>
</spoiler>

== Signature Declaration ==

The <enforce inline>ScriptInvoker</enforce> class used above is the "default" one used for methods without arguments.
In order to provide arguments to the subscribed methods, a generic {{Link/Enfusion|armaR|ScriptInvokerBase}} type must be used, e.g <enforce inline>ScriptInvokerBase<TypeA, TypeB, TypeC></enforce>.

A method signature can be declared using {{hl|typedef}}:
<enforce>
void ScriptInvokerIntMethod(int i);
typedef func ScriptInvokerIntMethod;
typedef ScriptInvokerBase<ScriptInvokerIntMethod> ScriptInvokerInt;
</enforce>

And used like this:
<enforce>
protected ref ScriptInvokerInt m_OnEventWithIntParameter = new ScriptInvokerInt();
</enforce>

<spoiler text="Show full example">
<enforce>
class TAG_EventHolder
{
protected in m_iScore;
protected ref ScriptInvokerInt m_OnScoreChanged; // still created on request

ScriptInvokerInt GetOnScoreChanged()
{
if (!m_OnScoreChanged)
m_OnScoreChanged = new ScriptInvokerInt();

return m_OnScoreChanged;
}

void AddScore(int points)
{
m_iScore += points;

if (m_OnScoreChanged)
m_OnScoreChanged.Invoke(m_iScore);
}
}

class TAG_Subscriber
{
protected TAG_EventHolder m_EventHolder;

protected void WarnOfScoreChange(int newScore) // note the similarity with ScriptInvokerIntMethod's signature
{
Print("The score is now " + newScore + "!", LogLevel.NORMAL);
}

void Subscribe(notnull TAG_EventHolder eventHolder)
{
if (!eventHolder)
return;

if (m_EventHolder)
UnSubscribe();

eventHolder.Insert(WarnOfScoreChange); // if the method signature were not matching, the compiler would warn here
m_EventHolder = eventHolder;
}

void UnSubscribe()
{
if (!m_EventHolder)
return;

m_EventHolder.Remove(WarnOfScoreChange);
m_EventHolder = null;
}

void ~TAG_Subscriber()
{
UnSubscribe();
}
}
</enforce>
</spoiler>

That's it! Remember that ScriptInvokers/Event Handlers are very powerful, but dangerous tools. Be sure not to fall into any trap or loop!

{{GameCategory|armaR|Modding|Tutorials|Scripting}}