No more modes?
brendan at mozilla.com
Thu Oct 14 13:48:19 PDT 2010
On Oct 14, 2010, at 1:39 PM, Jeff Walden wrote:
> On 10/14/2010 08:29 AM, Brendan Eich wrote:
>> Thus there is already one bit of opt-in versioning state in ES5, which must be carried from direct eval's caller to callee.
> SpiderMonkey currently does this,
I wasn't describing any implementation, I was citing ES5 10.1.1, second bullet:
* Eval code is strict eval code if it begins with a Directive Prologue that contains a Use Strict Directive or if the call to eval is a direct call (see 220.127.116.11.1) to the eval function that is contained in strict mode code.
> but fairly shortly (I have patches) it will not. The eval *function*'s implementation will always perform indirect eval, and only the eval opcode will perform direct eval. (We could statically distinguish strict+direct from non-strict+direct, too, with a separate opcode, but since it's trivial to query the currently executing script's strictness, runtime detection seems better than burning an opcode.)
> That's only SpiderMonkey, of course, but as far as I can tell the concepts are applicable to any ECMAScript implementation.
This is an implementation detail, independent of ES5 10.1.1 and unobservable unless there's a bug.
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