Function Reference: Difference between revisions

A simple example: imagine a function invoked on an object that takes a parameter that points to another object of the same class: '''car1.Ram(car2)''' (which should ram your car into another car). Obviously, the car cannot ram itself. By using the "Self" variable, we can ensure that car2 is not equal to Self and prevent damaging or unnecessary code from executing:

<br>

;The function is called on one car like this.

Car1.Ram(car2)

  endIf

endFunction

<br>

Another example is a script that is trying to release an object it no longer needs so that the reference no longer consumes memory. However due to the its complexities, the script may accidentally end up referencing the same object. A reference to an object that was expected to be released is called a dangling pointer, and it can cause crashes or other problems as the application progresses. By comparing newObject to Self (''if(newObject != Self)''), we can be sure that when the old object is released it will be properly replaced by newObject.

=== Examples ===

; A simple function that adds the two values together and returns the result

; Global, because it doesn't need a self variable

   return a + b

endFunction

<br>

; A function that increments a value on this script by the specified amount.

; The amount has a default value of 1 (so the caller doesn't have to pass it)

   myValue += howMuch

endFunction

== Special Variables ==

=== Examples ===

; Pass our self off to another function

SomeObject.OtherFunction(self)

<br>

; Call the parent's version of DoStuff, ignoring our local definition

Parent.DoStuff()

== Calling Functions ==

=== Examples ===

; Call the function: MyFunction(int a, int b) and get the result and put it in x

x = MyFunction(1, 2)

<br>

; Call the function DefaultFunction(float a, float b, float c = 0.0, float d = 1.0) on MyObject,

; but only pass in the first three parameters

MyObject.DefaultFunction(4.0, 2.0, 1.0)

<br>

; Call the function DefaultFunction(float a, float b, float c = 0.0, float d = 1.0), but specify

; argument d out of order because we want c to keep the default it has

DefaultFunction(5.0, 2.4, d = 2.0)

<br>

; Call the global function MyGlobal() in the Utility script

Utility.MyGlobal()

<br>

<br>'''Example:'''

myRefAliasScript property refScript auto      ;fill this property with your quest in the CK editor

refScript.myRefAliasScriptFunction01()

refScript.myRefAliasScriptFunction02()        ;access two functions that are in the reference alias script

<br>'''Example One:'''<br>

''Access the script functions on a created ObjectReference:''

ObjectReference Pony1 = PlayerRef.PlaceAtMe(myCustomPony)  ;create two ponies. Let us assume that myCustomPony is a base Actor that has 'PonyScript.psc' attached to it.

ObjectReference Pony2 = PlayerRef.PlaceAtMe(myCustomPony)

Pony1Script.groomPony()                                    ;groom pony one, using the groomPony() function in (its instance of) PonyScript

Pony2Script.killPony()                                      ;kill pony two, using the killPony() function in (its instance of) PonyScript

<br>Note: sometimes you will have to cast the object with ScriptB attached to it before declaring the variable will work. Let us say that Pony1 was an Actor instead of an ObjectReference, for instance. Since PonyScript extends ObjectReference, we first need to cast Pony1 ''as an ObjectReference'' before we can cast it ''as a PonyScript'', otherwise the compiler will throw out errors:

Actor Pony1 = somePony

PonyScript Pony1Script = (Pony1 as ObjectReference) as PonyScript

'''Example Two:'''<br>

''Find an Actor's linked reference, and conditionally access the script functions on that reference:''

ObjectReference possibleTable1 = Actor1.GetLinkedRef()

if (possibleTable1 as Furniture) == magicTable                        ;is the actor linked to a magicTable?

   TableScript1.explode()                                              ;if so, use the magicTable's script function to make the magicTable explode!

endif

<br><br>

== Notes ==

Consider the following 4 scripts:

ScriptName ScriptA extends ObjectReference

endFunction

Suppose we call '''ScriptD.foo()'''. We might expect the output to be,

So, the execution order of the above is actually:

ScriptD.foo()

     parent.foo()

     parent.foo()

ScriptA.foo()

As a final example, if you had scripts in the following hierarchy...

ScriptName Script1 extends ObjectReference

function foo()

     parent.foo()

endFunction

...'''foo()''' would be called 10 times; Script10's version once, and Script1's version 9 times.