Magic Variables: Difference between revisions

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== Introduction ==
{{TOC|side}}
__NOEDITSECTION__
Magic variables are engine-maintained [[Variables|variables]] that serve a specific purpose within a given scope and are often used by the engine to provide data to a [[Script File|script]] or [[Code|code]] fragment.<br>
They are usually no longer present after leaving the scope (e.g. after code execution or after a [[forEach]]-statement).


'''Magic variables''' are engine maintained [[Variables|variables]] that serve a specific purpose within a given scope and are often used by the engine to push data to a given [[Script (File)|script]] or [[Code|code]] fragment. They are usually no longer present after leaving the scope (e.g. after code execution or after a [[forEach]] statement).
=== _this ===


Used to make the arguments of a script call ([[call]], [[exec]], [[execVM]], [[spawn]]) visible and accessible to the script. Also used by [[:Category:Event Handlers|Event Handlers]] to provide parameters.


''See also: [[this]]''
=== _x ===


Represents the current element during iteration with [[apply]], [[count]], [[configClasses]], [[configProperties]], [[findIf]], [[forEach]] and [[select]].


== Usage ==
{{ArgTitle|3|_y|{{GVI|arma3|2.02}}}}


==== _this ====
Iterating over a [[HashMap]] with [[forEach]] will return the key as [[#x|_x]] and the value as [[#y|_y]].
probably the most frequently used magic variable, which is used to make arguments of a script call ([[call]], [[exec]], [[execVM]], [[spawn]]) visible and accessible to the script.


==== _x ====
{{ArgTitle|3|_exception|{{GVI|arma1|1.00}}}}
represents the current element during a loop with: [[apply]], [[count]], [[configClasses]], [[configProperties]], [[findIf]], [[forEach]], [[select]].


==== _forEachIndex ====
[[Exception handling]] using a [[try]]-[[catch]]-statement declares this variable which contains details about the [[throw|thrown]] exception in the [[try]]-block.
represents the (zero-based) index of a [[forEach]] [[#x|_x]]'''.


==== thisList''', '''thisTrigger ====
{{ArgTitle|3|_fnc_scriptName|{{GVI|arma3|1.00}}}}
variable defined by [[Triggers]], which are however only accessible within the activation or deactivation script.  


==== _exception ====
{{Feature|informative|Not engine-maintained, but added by {{hl|functions_f/initFunctions.sqf}} – see [[scriptName]].}}
[Exception handling]] using a [[try]]..[[catch]] statement declares this variable which contains details about the [[throw|thrown]] exception in the try block.
Within a [[:Category:Functions|Function]], the {{hl|TAG_fnc_functionName}} function name (e.g. {{hl|"myTag_fnc_myFunction"}}).


==== _thisScript ====
{{ArgTitle|3|_fnc_scriptNameParent|{{GVI|arma3|1.00}}}}
is the [[spawn|spawned]] script handle from within itself since {{arma3}}.


==== _thisEventHandler ====
{{Feature|informative|Not engine-maintained, but added by {{hl|functions_f/initFunctions.sqf}} – see [[scriptName]].}}
Since Arma 3 v.1.63.137807, the script handle (not the EH index!) for Event Handlers added with [[addEventHandler]] or [[addMPEventHandler]].
Within a [[:Category:Functions|Function]], the name of the function that called the current function (same as [[#fnc_scriptName|_fnc_scriptName]] if the function was not called by another function).


==== _pos,_alt,_shift,_units ====
{{ArgTitle|3|_forEachIndex|{{GVI|arma2oa|1.55}}}}
See [[onMapSingleClick]]
 
Represents the (zero-based) index of a [[forEach]]- / [[forEachReversed]]-loop.
 
{{ArgTitle|3|_self|{{GVI|arma3|2.14}}}}
 
Available in HashMapObject methods. Contains the HashMapObject instance that the method was invoked on (see [[createHashMapObject]]).
 
{{ArgTitle|3|_thisArgs|{{GVI|arma3|2.04}}}}
 
Additional Event Handler arguments available with [[addMissionEventHandler]].
 
{{ArgTitle|3|_thisEvent|{{GVI|arma3|2.06}}}}
 
The name of the Event added with [[addEventHandler]], [[addMPEventHandler]], [[addMissionEventHandler]],[[addUserActionEventHandler]], [[ctrlAddEventHandler]] and [[displayAddEventHandler]], as well as for config types EHs.
 
{{ArgTitle|3|_thisEventHandler|{{GVI|arma3|1.64}}}}
 
The index for Event Handlers added with [[addEventHandler]], [[addMPEventHandler]], [[addMissionEventHandler]], [[addUserActionEventHandler]], [[ctrlAddEventHandler]] and [[displayAddEventHandler]].
 
{{ArgTitle|3|_thisFSM|{{GVI|arma3|1.54}}}}
 
The [[FSM]] ID for FSMs executed with [[execFSM]].
 
{{ArgTitle|3|_thisScript|{{GVI|arma3|1.54}}}}
 
The [[Script Handle]] of a script started with [[execVM]], [[call]] or [[spawn]].
 
{{ArgTitle|3|_thisScriptedEventHandler|{{GVI|arma3|1.68}}}}
 
The index for Scripted Event Handlers added with [[BIS_fnc_addScriptedEventHandler]].
 
=== _time ===
 
{{Feature|warning|[[SQS Syntax|SQS]] only.}}
The time elapsed since the script started running.
 
=== this ===
 
* '''Addon Config Files''' (e.g. UserActions, onInit, etc.)''':''' The object to which the entry belongs.
* '''Dialogs:''' The player unit that activated control (e.g. via mouseEnter). [[false]] if non-activated.
* '''Object Init Fields:''' The object to which the init field belongs.
* '''Triggers:'''
** ''Condition'': The [[Boolean]] return value of the [[Trigger]]'s condition (e.g. "East Not Present").
** ''On Activation'' and ''On Deactivation'': Seems to always return [[false]].
* '''Waypoints:'''
** ''Condition'', ''On Activation'' and ''On Deactivation'': The group leader that completed the waypoint (or the driver, if the waypoint is assigned to a vehicle).
 
=== thisList ===
 
* '''Triggers:'''
** Accessible in the ''Condition'', ''On Activation'' and ''On Deactivation'' code.
** Defines an array of objects that have been detected by the trigger (same as what is returned by the [[list]] command).
** Seems to be undefined in the ''On Deactivation'' expression and should not be used. It will either be an empty array, or possibly the contents of a different trigger.
* '''Waypoints:'''
** Accessible within the ''Condition'' or ''On Activation'' code.
** Defines an array containing all group members that completed the waypoint.
 
=== thisTrigger ===
 
Refers to the [[Triggers|trigger]] object itself - accessible within the ''Condition'', ''On Activation'' and ''On Deactivation'' code.


==== _id,_uid,_name,_jip,_owner ====
See [[onPlayerConnected]]




[[Category: Scripting Topics]]
[[Category: Scripting Topics]]
[[Category: Operation Flashpoint: Editing]]
[[Category: ArmA: Editing‏‎]]
[[Category: ArmA 2: Editing‏‎]]
[[Category: Arma 3: Editing]]

Latest revision as of 00:25, 13 April 2025

Magic variables are engine-maintained variables that serve a specific purpose within a given scope and are often used by the engine to provide data to a script or code fragment.
They are usually no longer present after leaving the scope (e.g. after code execution or after a forEach-statement).

_this

Used to make the arguments of a script call (call, exec, execVM, spawn) visible and accessible to the script. Also used by Event Handlers to provide parameters.

_x

Represents the current element during iteration with apply, count, configClasses, configProperties, findIf, forEach and select.

_y

Iterating over a HashMap with forEach will return the key as _x and the value as _y.

_exception

Exception handling using a try-catch-statement declares this variable which contains details about the thrown exception in the try-block.

_fnc_scriptName

Not engine-maintained, but added by functions_f/initFunctions.sqf – see scriptName.

Within a Function, the TAG_fnc_functionName function name (e.g. "myTag_fnc_myFunction").

_fnc_scriptNameParent

Not engine-maintained, but added by functions_f/initFunctions.sqf – see scriptName.

Within a Function, the name of the function that called the current function (same as _fnc_scriptName if the function was not called by another function).

_forEachIndex

Represents the (zero-based) index of a forEach- / forEachReversed-loop.

_self

Available in HashMapObject methods. Contains the HashMapObject instance that the method was invoked on (see createHashMapObject).

_thisArgs

Additional Event Handler arguments available with addMissionEventHandler.

_thisEvent

The name of the Event added with addEventHandler, addMPEventHandler, addMissionEventHandler,addUserActionEventHandler, ctrlAddEventHandler and displayAddEventHandler, as well as for config types EHs.

_thisEventHandler

The index for Event Handlers added with addEventHandler, addMPEventHandler, addMissionEventHandler, addUserActionEventHandler, ctrlAddEventHandler and displayAddEventHandler.

_thisFSM

The FSM ID for FSMs executed with execFSM.

_thisScript

The Script Handle of a script started with execVM, call or spawn.

_thisScriptedEventHandler

The index for Scripted Event Handlers added with BIS_fnc_addScriptedEventHandler.

_time

SQS only.

The time elapsed since the script started running.

this

  • Addon Config Files (e.g. UserActions, onInit, etc.): The object to which the entry belongs.
  • Dialogs: The player unit that activated control (e.g. via mouseEnter). false if non-activated.
  • Object Init Fields: The object to which the init field belongs.
  • Triggers:
    • Condition: The Boolean return value of the Trigger's condition (e.g. "East Not Present").
    • On Activation and On Deactivation: Seems to always return false.
  • Waypoints:
    • Condition, On Activation and On Deactivation: The group leader that completed the waypoint (or the driver, if the waypoint is assigned to a vehicle).

thisList

  • Triggers:
    • Accessible in the Condition, On Activation and On Deactivation code.
    • Defines an array of objects that have been detected by the trigger (same as what is returned by the list command).
    • Seems to be undefined in the On Deactivation expression and should not be used. It will either be an empty array, or possibly the contents of a different trigger.
  • Waypoints:
    • Accessible within the Condition or On Activation code.
    • Defines an array containing all group members that completed the waypoint.

thisTrigger

Refers to the trigger object itself - accessible within the Condition, On Activation and On Deactivation code.