Es4-discuss Digest, Vol 8, Issue 44
brendan at mozilla.org
Tue Oct 30 16:58:12 PDT 2007
On Oct 30, 2007, at 3:59 PM, Yehuda Katz wrote:
> I would specifically like to hear a realistic technical scenario
> where the implementation of ES4 produces serious complications in
> the open web.
Me too. Here's one analysis of how ES4 might break existing scripts:
* New keywords and syntax hanging off them. Already addressed by not
opening the __ES4__ namespace without opt-in version selection, e.g.
by <script type="application/ecmascript;version=4">. See the
versioning proposal at
* Intentional incompatibilities. Today we knocked down three proposed
* Unintended incompatibilities: these have to be addressed by testing
the reference implementation, other implementations, and the spec-
language (run by one's brain). This is an auditing procedure, QA.
Often coverage is a problem, but we have had good experiences with
fuzz-testing JS and intend to fuzz the RI.
Hope this helps.
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