为什么ECMAScript第4版完全废弃了？ [英] Why was ECMAScript 4th edition completely scrapped?

问题描述

我一直在寻找有关报废的ECMAScript第4版的一些信息，但即使在SO上也没有取得多大成功。我知道Mozilla的JavaScript 1.7实现了第4版中提供的许多（全部？）新功能，我想我记得它上面有一篇好的John Resig帖子，但我现在似乎无法在他的博客上找到它。

I've been looking for some information regarding the scrapped ECMAScript 4th Edition without much success, even on SO. I know Mozilla's JavaScript 1.7 implemented many (all?) of the new features offered in 4th Edition and I thought I remembered a good John Resig post on it but I can't seem to find it on his blog now.

特别是，我想知道为什么它完全取消了ECMA-262第5版以及为什么它不仅仅是改进了。有些功能非常酷，比如生成器，迭代器，let，新赋值运算符和（我特别喜欢的）解构赋值。

In particularly, I want to know why it was completely scrapped in favour of ECMA-262 5th Edition and why it wasn't just improved upon. Some of the features are pretty cool, like generators, iterators, let, new assignment operators and (my particular favourite) destructuring assignment.

我知道所有这些特殊功能都会只是在具有过时ECMAScript实现的浏览器中抛出错误，但为什么不将它们包括在内，知道有一天这些实现很少而且很远？还有其他原因吗？我们是否可能会在未来的版本中看到一些报废功能再次出现，或者供应商是否害怕破坏兼容性，我们可能永远不会看到标准的这些改进？

I know all of those particular features would just throw errors in browsers with out-of-date ECMAScript implementations, but why not include them anyway with the knowlege that one day those implementations would be few and far between? Were there other reasons too? Are we likely to see some of the scrapped features reappear in a future release, or are vendors so scared of breaking compatibility that we will probably never see such improvements to the standard?

顺便说一句，知道一些关于这个问题的意见会很高兴，你是否因为看到第5版的一些功能而感到恼火，或者你觉得这样更好？是否值得玩ECMAScript 4的实现？

As an aside, it would be nice to know some opinions on the matter, are you annoyed to see some features cut from the 5th Edition or do you think it's better this way? Is it worth playing around with implementations of ECMAScript 4?

推荐答案

简单地说，是没有ECMAScript第4版。来自第5版规范：

Simply put, there was no ECMAScript 4th Edition. From the 5th edition specification:

为开发第四版ECMAScript做了大量工作。虽然这项工作没有完成，也没有作为ECMAScript的第四版出版，但它通知了该语言的不断发展。目前的第五版ECMAScript（作为ECMA-262第5版出版）编纂了语言规范的事实上的解释，这些解释在浏览器实现中变得很普遍，并且增加了对自第三版出版以来出现的新功能的支持。

Significant work was done to develop a fourth edition of ECMAScript. Although that work was not completed and not published as the fourth edition of ECMAScript, it informs continuing evolution of the language. The present fifth edition of ECMAScript (published as ECMA-262 5th edition) codifies de facto interpretations of the language specification that have become common among browser implementations and adds support for new features that have emerged since the publication of the third edition.

基本上，关于如何推动JavaScript向前发展有很多非常强烈的意见，其中许多是不兼容的，其中一些主要是组装的在事情崩溃之前，有些人认为是第四版（尤其是因为缺乏一些重要的实施者的支持）。与此同时，该标准的新版本已经非常非常过期，因此经过多次提前谈判后，各方在2008年7月在奥斯陆聚会并达成了一致意见（Brendan Eich [JavaScript的发明者]后来称这种方法 Harmony 撰写时。

Basically, there were a lot of very strong opinions about how to move JavaScript forward, many of which were incompatible, some of which had mostly been assembled into what some thought would be the 4th edition before things fell apart (not least because of lack of support from some important implementors). Meanwhile, a new edition of the standard was very, very overdue, and so after a lot of advance negotiation, the various parties got together in Oslo in July 2008 and agreed a way forward (Brendan Eich [inventor of JavaScript] later termed that approach "Harmony" when writing it up).

和谐推迟了一些事情，永远把一些东西放在桌子上（命名空间，包，早期绑定）， —重要的 —允许委员会推进自1999年以来的第一次规范更新：第5版。

Harmony deferred some things, put some things completely off the table forever (namespaces, packages, early binding), and — importantly — allowed the committee to move forward with the first specification update since 1999: The 5th edition.

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