Comments on: AS3 technique — using object instances as “enums”

By: Samuel Asher Rivello

Samuel Asher Rivello — Wed, 12 Aug 2009 00:19:18 +0000

Enums are my favorite community developed language feature!!!

An Enum is a kind of variable that is not natively available in ActionScript 3.0, but can be found in other languages such as C++. An enum is a type with a restricted set of values.

Here is a demo;
http://www.blog.rivello.org/?p=621

By: Troy Gardner

Troy Gardner — Mon, 30 Jul 2007 02:43:21 +0000

Paco: the enum object is a full blown class so can have whatever id/strings you want to serialize, and as many methods as you want to marshal bac and forth (e.g. toXMLString(), fromXMLString());

Sho:
I profiled use of String/int,uint, number in switch statements and using ‘enum’s was fastest by 1/3 of the String time when you cache a refence locally. The reason for this is it uses identity (===) rather than value comparisons (==). I cache a copy. Here’s some sample code

public static const A:MyEnum = MyEnum.A;

….
switch(someEnum){
case A:
break;
case B:
}

By: Paco

Paco — Thu, 17 May 2007 20:16:16 +0000

The TypeSafe method is not really useful when you want to save this information into a database. I would prefer to save a number.

A number is also easier to transport between the various software of a system. From flex program to businessObject to database.

I want to ask for a specific enumeration type in my function parameter like the TypeSafe allow me, but I don’t want to save this object into my database. I want to save a byte no more!

Why they never build a real Enumeration structure in AS# !?

By: ivan

ivan — Thu, 28 Dec 2006 20:38:47 +0000

The above approach still isn’t quite “typesafe” since you can use “new LoopResult()” instead of one of the consts, which would pass compilation but would break the code at runtime. If constructors were allowed to be declared private, then it’d be less of a kludge. Bottom line — AS needs proper enums.

By: Sho

Sho — Wed, 05 Apr 2006 16:03:35 +0000

I’m glad that Java 5 has enums and generics. Maybe we can get them into AS4? :-)

I started writing a reply here, but it ended up getting quite long so I’m moving it to a new entry. Let me know what you think.

By: Jens Halm

Jens Halm — Wed, 05 Apr 2006 15:08:06 +0000

But in Java 5 you can at least switch on “real” enums.

Btw: If only Adobe would not prevent private and protected constructors, it would make life so much easier for creating singletons and faking enums and abstract classes. Still don’t know why they are not allowed any more…

By: Sho

Sho — Tue, 04 Apr 2006 21:59:40 +0000

Peter: Great comments. I hadn’t thought about the AS3 “switch on any type” aspect.

Jason: Glad to see we’re on the same page. Thanks for the link.

By: Jason Nussbaum

Jason Nussbaum — Tue, 04 Apr 2006 21:39:37 +0000

I blogged something like that for AS 2 way back…
http://blog.jasonnussbaum.com/?p=48

With some added toString methods and all that jazz…

By: Campbell

Campbell — Tue, 04 Apr 2006 21:23:38 +0000

Yeah cool,
I have been doing similar, thought id try it after using the internal struc & enum class types in c#.

Cam

By: Peter

Peter — Tue, 04 Apr 2006 20:07:59 +0000

This technique is particularly nice in AS3, compared to Java, because AS3 lets you switch on any type. But I’d still consider adding a string property to the class, for use in debugging.