ES3.1 Draft: 11 June 2008 version available

[Maciej Stachowiak]

On Jun 12, 2008, at 9:45 AM, Sam Ruby wrote:

> I'm trying to understand the nature of the ES3.1 - ES4 subset
> relationship that this committee has agreed to.
>
>> p69 12.10.  Disallowing the with statement in strict mode breaks the
>> ES3.1 - ES4 subset relationship (we've found no compelling reason to
>> ban it).
>
> How does having ES4 support *more* than ES3.1 supports break the
> subset relationship?

Having ES3.1 strict mode forbid features that ES4 strict mode does not  
(but which are in both languages) feels like breaking the subset  
relationship to me. The reason is that program that is purely ES3 but  
has the strict mode pragma added could then be legal in one language  
but not the other, which seems problematic.

To the extent that strict mode limits ES3-with-pragma programs, I  
think it should impose the same limits in ES3.1 and ES4.

Regards,
Maciej