scope question

[silentweed]

I have the following code:

start();
function start():Void{
	var someNumber:Number = 15;
	}
	
_root.onEnterFrame = function():Void{
	trace(someNumber); //this gives undefined which is fine and i understand
}

However what i dont understand is when i modify the code to :

start();
function start():Void{
	someNumber = 15;
	}
	
_root.onEnterFrame = function():Void{
	trace(someNumber); // This actually gives the value 15 instead of undefined like i expected
}

Does anybody know why this is so? cheers in advance

[cancerinform]

var someNumber:Number = 15;

Here you are declaring a local variable only for that function. Will stay within that function only.

someNumber = 15;

here it is assumed you have declared the variable somewhere else before already. It is not local to the function any more.

[silentweed]

oh thanks for that..so even though i have not declared it before, it just ASSUMES I have declared it?

[cancerinform]

In AS1 you can do that without the var declaration. In AS2 class file you would get an error, if the var had not been declared before.

[silentweed]

Cheers for that but if you look at the code (which is in it's entirety) below:

start();
function start():Void{
	someNumber = 15;
	}
	
_root.onEnterFrame = function():Void{
	trace(someNumber); // This actually gives the value 15 instead of undefined like i expected
}

I have NOT actually declared the variable someNumber before and yet i get no error and it traces out the correct value. (Also the publish settings are set to AS2 and player 7)

If you simply copy and paste the above code in a new flash movie you will see what i mean

[silentweed]

bump

[Q__Hybrid]

Silent,

The Interpreter in ActionScript automatically scopes all variables within a function that are not declared with "var" to the timeline that contains the function, not the function itself.

It's a quick and dirty shorthand used to access variables that are both local and external from within a function body, whether the variables already exist or not.

That's why it's always good to qualify your references. It's easy for things like this to ruin a project.
+Q__

[silentweed]

Thanks for that Q was'nt aware of that!! Cheers 4 the help