2.7.1 Access to Underlying Data

As shown in the example from the previous section, this in abstract methods refers to the underlying data. For AbstractInt methods, this is therefore a variable of type Int.

abstract AbstractInt(Int) {
  inline public function new(i:Int) {
    this = i;
  }
}

since Haxe 4.3.0

The abstract keyword can be used in abstract methods to refer to the current instance as an abstract type, rather than referring to the underlying data with the this keyword.

This can be useful when an abstract method needs to call other methods which accept an argument of the abstract type. For example, suppose class Main defines a method takeAbstractInt:

  static public function takeAbstractInt(x:AbstractInt) {
    // ...
  }

To call takeAbstractInt from within an AbstractInt method, we must use the abstract keyword:

  inline public function test() {
    Main.takeAbstractInt(abstract);
  }

If we instead wrote Main.takeAbstractInt(this), this would be a type error, because takeAbstractInt does not accept an argument of type Int.

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