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Still learning AS3? Believe or not, but AS4 is on the way

Carlos Pinho
By | 2008-02-20T15:40:51+00:00 Feb 20, 2008|Old Posts|

The fourth edition of the ECMAScript language (ES4) represents a significant evolution of the third edition language (ES3), which Ecma approved as the standard ECMA-262 in 1999. ES4 is compatible with ES3 and adds important facilities for programming in the large (classes, interfaces, namespaces, packages, program units, optional type annotations, and optional static type checking and verification), evolutionary programming and scripting (structural types, duck typing, type definitions, and multimethods), data structure construction (parameterized types, getters and setters, and meta-level methods), control abstraction (proper tail calls, iterators, and generators), and introspection (type meta-objects and stack marks).

ES4 also upgrades ES3 in small ways by fixing bugs, improving support for regular expressions and Unicode, supplying richer libraries, and adding lightweight facilities like xype-discriminating exception handlers, constant bindings, proper block scoping, destructuring binding and assignment, succinct function expressions and definitions, and array comprehensions.

Check the proposed ECMAScript 4th Edition.

Here is also some notes from which describes main differences.

About the Author:

Carlos Pinho
A father, a husband and a geek... Carlos was the founder of projects like The Tech Labs and Flash Enabled Blog. He is the founder of TekTuts He is passionate about technologies. Their main skills are in analytics, transport & logistics, business administration. He also writes about programming resources, trends, strategy and web development.


  1. mattjpoole February 20, 2008 at 3:54 pm - Reply

    Note that AS3 is based on the previously unreleased version of ES4.

    This can be seen in a few of the missing features of AS3 for example the lack of support for private constructors. When AS3 was released it was unclear as to whether private constructors would be supported in the final ES4 standard so Adobe omitted support to be safe.

    So while there may be some differences many of the features are fully supported in AS3 already…

  2. Saeed Ashour February 20, 2008 at 6:04 pm - Reply

    Hi …

    i thought AS 3.0 is based n ECMAscript edition 4 >>> i dunno why all people thinks there will be a new version of AS? if you can explain that to me .

  3. Carlos Pinho
    Carlos Pinho February 20, 2008 at 11:10 pm - Reply

    AS3 is based on ES4, although as matt described, the final release of ES4 wasn’t yet available. When i mentioned AS4, i mean an update of actual AS3 in order to support the new available features, that Adobe has omitted.

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