Newly revised Section 10 for ES3.1.

Mark Miller erights at
Wed Jul 9 23:37:11 PDT 2008

2008/7/9 Allen Wirfs-Brock <Allen.Wirfs-Brock at>:
> This is currently stated in section 4.2.2 of the draft as:
> With one exception, an ECMAScript program that is voluntarily limited to a
> usage subset  and which executes without error under the subset's
> restrictions will behave identically if executed without on any usage subset
> restrictions. The exception is any situation where the operation of such a
> program depends upon the actual occurrence and subsequent handling of
> additional error conditions that are part of the subset.

I like and agree with that text. My point exactly is your exception
above: a valid program may react to a subset-induced error condition.

ES4 folks,

What are the compatibility relationships between ES4 opt-in, ES4
opt-in strict, ES4 strict, and ES4? I think it's clear that ES4 opt-in
strict is a subset of ES4 opt-in. Are there any other subset
relationships among them? I hadn't realized till just now how large
the gulf might be between ES4 opt-in and ES4. Do opt-in and strict
define orthogonal switches? Can opt-in and non-opt-in programs
co-exist in the same frame (global object)? We all need to clarify
these issues.

Text by me above is hereby placed in the public domain


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