Any type error

1

Total haxe beginner here. I have class A with a public prop theX

Then l have class B with a List that currently is populated with instances of class A but it could be other types aswell. In B l have a method that needs to pull out an instance from the List and set instanceA.theX = 1; but the compiler complains that there is no such prop on A. Is’nt this how Any could be used? What could be wrong here? Thanks

2

You need to promote type when you get instance:

final list:List<Any> = [new A()];
final a:A = list[0];
trace(a.x);

You can also use such typing, if all list items have same property:

final list:List<{x:Float}> = [new A()];
trace(list[0].x);
3

Great! Thanks @RblSb

4

You’ll have to check if the object is of type A before doing that, or you’ll get error at runtime.

final a = cast(list[0], A);
if (a != null) {
   trace(a.x);
}

@tubbs can you share what you are trying to do? List<Any> is rarely something you’d need.

5

l have already declared and instanced the List as an empty list in the constructor of B and then l have some methods in B like below:

addItem(someInstance:Any){

myList.add(someInstance);
}

setTheX(x:Int){
var aInstance:Any = myList[0];
aInstance.theX = x;
}

I guess that explains what l’m trying to achieve. How would you do that?

6

What I mean is, what are you storing in the list? If you are only storing object from A you can do List<A>, or maybe the object share a parent class you could use?

7

I would like the list to be able to hold more types than just A but they would all have theX property.

8

In that case @RblSb’s solution would work, List<{ theX: Int }>, and you don’t need any Any in the code with this.
It also work on functions function addItem(someInstance:{theX:Int}) {.

9

ok thanks alot!

10

That’s exactly how you will get a runtime error though. :smiley: A safe cast like that doesn’t return null on failure, it throws an exception. Maybe you were looking for Std.downcast().