JS OOP trouble

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1

i have a script called skills.js :

class Skill {
	var damage: float;
	var rate : float;
	var hits : int;
	var selected : boolean;
	var name : String;

	function Skill(nam : String, dmg : float, rat : float, hit : int, sel : boolean){
		this.damage = dmg;
		this.rate = rat;
		this.hits = hit;
		this.selected = sel;
		this.name = nam;
	} 
}

punch = new Skill("punch", 5, 0.2, 1, false);
slash = new Skill("punch", 3, 0.1, 1, false);
headbutt = new Skill("punch", 8, 1, 1, false);
push = new Skill("punch", 2, 0.6, 1, false); `

and i want to access the it’s values properties in another script. for example in player.js:

var damage = skillScript.punch.damage;

but is won’t let me and it returns as a log warning when ever i start the game up. if somebody knows what i need to do please help. thanks for reading and here is the error if it helps:

NullReferenceException: Object reference not set to an instance of an object
Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.String cacheKeyName, System.Type[] cacheKeyTypes, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.Object[] args, System.String cacheKeyName, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
Boo.Lang.Runtime.RuntimeServices.GetProperty (System.Object target, System.String name)
UnityScript.Lang.UnityRuntimeServices.GetProperty (System.Object target, System.String name)
player.FixedUpdate () (at Assets/Scripts/player.js:54)

glad i could help and sorry for the inconvinience again

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ill add an answer to both of your questions so that you can accept them and make it easy for future visitors to identify the problem

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1 Answer

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It seems you want punch, slash etc. to be global variables. The equivalent to global in Unity is static - you must declare them this way:

static var punch = new Skill("punch", 5, 0.2, 1, false);
static var slash = new Skill("punch", 3, 0.1, 1, false);
static var headbutt = new Skill("punch", 8, 1, 1, false);
static var push = new Skill("punch", 2, 0.6, 1, false);

You can access these globals in other scripts using the script name:

  var damage = skills.punch.damage;

thanks it works like magic

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That is actually incorrect. Static is NOT global. Static makes a variable a class variable as opposed to an instance variable. The following line is perfectly legal, but is not a global variable: private static var punch = ...; only the public modifier makes a variable global (its the default in js). Static has nothing to do with the variable's accessibility level.

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@Peter G Wait, are you saying the public keyword alone is sufficient to make a var a global or are you saying public + static keywords make a global? Would you call the first of these two a global? public var punch = ...; public static var punch = ...; So far, I had been under the impression static was enough to define a global, but I'd have no problem to learn that public static is required. But only public...? now that would break my view of the world...? :p

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What he said is correct - I should had read his comment more carefully. static var is the same as public static var (public is default in Unityscript), and defines a global scope variable. If you write private static var you create a variable with program life, but script scope. By the way, a static variable exists even if you don't ever instantiate the script where it's defined, and continue existing if you destroy that script (at least the public ones).

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Complementing: public alone doesn't make a variable global - it should be public static, but static alone does the job because public is default.

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