How to check typeof array<T>?

1

How to check typeof array?

  switch (Type.typeof(points)) {
  		case TClass(Array<Vector3>): //error
                              trace("vector3");
                      case TClass(Array<Vector2>): //error
                                                      trace("vector3");
                      case _:

and I got this error

Expected expression

2

I see two problems here. First, Haxe is interpreting the angle brackets as “greater than” and “less than” signs. So it thinks you wrote Array is less than Vector3 is greater than [blank]. It expects an expression after >, and when it doesn’t find one it throws an error. If this was the only problem, you could work around it by converting to string and examining the string.

But there’s also the second problem, which is that the information you’re looking for does not exist at runtime. At runtime, all arrays are Array<Dynamic>. Maybe points started out as an Array<Vector3>, maybe it was Array<Vector2>, or maybe even Array<Array<String>> (though I hope not). Type.typeof() can’t tell the difference.

I see a couple options:

  • Test the contents of the array. Type.typeof() can tell the difference between a Vector3 and a Vector2 no problem.
  • Write one function to handle Array<Vector3> and another to handle Array<Vector2>. Then you won’t have to deal with Type.typeof() at all.
  • Only use Vector3, but sometimes set z=0 so that it’s equivalent to Vector2.
  • Advanced option: use macros. Since they run at compile time, they can tell between the types of array.
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3

What you are doing is fundamentally wrong: parameter at TClass is what you get, not what you give. Here is a sample

		var as = new Array<String>();
		var vf = new Vector<Float>(10);

		switch (Type.typeof(vf)) {
  			case TClass(cl):
				trace(cl);
			case _:
				trace("nothing");
		}

resulting in

Main.hx:10: Array (CPP)
Main.hx:10: hl.types.$ArrayBase (HL)

because both array and vector are using the same base which is an array (where vector is like bounded array at runtime).

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