Comparing Haxe and ActionScript

2024-12-21

Since the Haxe programming language originated from an ActionScript 2.0 compiler, there are many similarities between the languages. In fact, a number of the minor differences between ActionScript 3.0 and Haxe can be explained if you understand this heritage.

However, as you look deeper, you will find that Haxe is a modern, strictly-typed language that takes inspiration from many of the best parts of ActionScript while adding many new and valuable features.

¶Basic Types

¶ActionScript 3

Boolean
int
Number
Object
void
Array
Vector.<String>

¶Haxe

Bool
Int
Float
Dynamic
Void
Array<Dynamic>
Array<String>

¶Package Declarations

¶ActionScript 3

1
2
3

package com.example.myapplication {
 
}

¶Haxe

1	package com.example.myapplication;

¶Defining a Class

¶ActionScript 3

public class MyClass {
 
   public function MyClass () {
 
 
   }
 
}

¶Haxe

class MyClass {
 
   public function new () {
 
 
   }
 
}

¶Loops

¶ActionScript 3

for (var i:uint = 0; i < 100; i++) {
 
}
 
for each (var value:String in items) {
 
}
 
for (var propertyName:String in object) {
 
}

¶Haxe

for (i in 0...100) {
 
}
 
for (value in items) {
 
}
 
var fields = Reflect.fields (object);
for (propertyName in fields) {
 
}

¶Switch Statements

¶ActionScript 3

switch (value) {
 
   case 1:
      trace ("Equal to 1");
      break;
 
   default:
      trace ("Not equal to 1");
      break;
 
}

¶Haxe

switch (value) {
 
   case 1:
      trace ("Equal to 1");
 
   default:
      trace ("Not equal to 1");
 
}

¶Type Inference

¶ActionScript 3

var hi = "Hello World";
 
// type is Object
// fails to compile in strict mode

¶Haxe

var hi = "Hello World";
 
// type is String
// even works for code completion

¶Type Casting

¶ActionScript 3

var car:Car = vehicle as Car;
 
var toString:String = String (10);
var toNumber:Number = Number ("10");
var toInteger:int = int (10.1);

¶Haxe

var car:Car = cast vehicle;
 
// or for a safe cast:
 
var car = cast (vehicle, Car);
 
var toString = Std.string (10);
var toNumber = Std.parseFloat ("10");
var toInteger = Std.int (10.1);

¶Type Details

¶ActionScript 3

if (vehicle is Car) {
 
}
 
import flash.utils.getDefinitionByName;
import flash.utils.getQualifiedClassName;
 
name = getQualifiedClassName (vehicle);
type = Class (getDefinitionByName (name);

¶Haxe

if (Std.is (vehicle, Car)) {
 
}
 
type = Type.getClass (vehicle);
name = Type.getClassName (type);

¶Checking for Null

¶ActionScript 3

if (object == null) {
 
}
 
if (!object) {
 
}

¶Haxe

1
2
3

if (object == null) {
 
}

¶Hash Tables

¶ActionScript 3

var table:Object = new Object ();
table["key"] = 100;
 
trace (table.hasOwnProperty ("key"));
 
for (var key:Object in table) {
 
   trace (key + " = " + table[key]);
 
}
 
delete table["key"];

¶Haxe

var table = new Map<String,Int> ();
table.set ("key", 100);
 
trace (table.exists ("key"));
 
for (key in table.keys ()) {
 
   trace (key + " = " + table.get (key));
 
}
 
table.remove ("key");

¶Rest Parameters

¶ActionScript 3

function test (...params):void {
 
}
 
test (1, 2, 3);

¶Haxe

function test (params:Array<Dynamic>) {
 
}
 
Reflect.makeVarArgs (test) (1, 2, 3);

¶Reflection

¶ActionScript 3

1
2
3

var foo = object["foo"];
 
bar.apply (this, [ "hi" ]);

¶Haxe

1
2
3

var foo = Reflect.field (object, "foo");
 
Reflect.callMethod (this, bar, [ "hi" ]);

¶Constants

¶ActionScript 3

1	private const gravity:Number = 9.8;

¶Haxe

1	private inline static var gravity = 9.8;

¶Function Types

¶ActionScript 3

function hello (msg:String):void {
 
}
 
var type:Function = hello;

¶Haxe

function hello (msg:String):Void {
 
}
 
var type:String->Void = hello;
 
// can also use Dynamic

¶Getters and Setters

¶ActionScript 3

function get x ():Number {
 
   return _x;
 
}
 
function set x (value:Number):void {
 
   _x = value;
 
}

¶Haxe

public var x (get, set):Float;
 
function get_x ():Float {
 
   return _x;
 
}
 
function set_x (value:Float):Float {
 
   return _x = value;
 
}

¶Read-Only Properties

¶ActionScript 3

function get x ():Float {
 
   return _x;
 
}

¶Haxe

public var x (default, null):Float;
 
// null allows private access
// `never` would restrict all access

¶Missing Features

Haxe does not currently support custom namespaces, and methods do not provide an arguments property.

¶Additional Features

In addition to most of the features of Actionscript 3, Haxe includes support for enums, type parameters (generics), structures, typedefs, custom iterators, conditional compilation, inlining and more.