Security Demands Simplicity (was: Private Slots)

David Bruant bruant.d at gmail.com
Sun Jan 20 11:16:46 PST 2013


Le 20/01/2013 19:01, Brendan Eich a écrit :
> David Bruant wrote:
>> Once again, the spec (well... you in that case :-) ) will do whatever 
>> is necessary to make the feature understandable by spec readers.
>> Transpilers will work with whatever is in the language. If they only 
>> have weakmaps, they'll use that. 
>
> See http://wiki.ecmascript.org/doku.php?id=harmony:harmony, in particular
>
>
>    Means
>
> 1.
>    Minimize the additional semantic state needed beyond ES5.
> 2.
>    Provide syntactic conveniences for:
>     1.
>        good abstraction patterns;
>     2.
>        high integrity patterns;
>     3.
>        defined by desugaring into kernel semantics.
>
>
> We aim to unify the "spec problem" and the "transpiler problem" where 
> possible.
I think the goal of providing syntactic conveniences defined by 
desugaring into kernel semantics is a valuable goal. It's good to reason 
about this semantics and it's good for transpilers.
I however disagree that it should be taken to the letter as Allen seems 
to take it. Specifically, I disagree with the idea that all kernal 
semantics should be exposed as runtime constructs. They should only if 
they prove to be useful for some other purpose.

> Not always, not necessarily by spec-by-desugaring.
> But we don't want magic in the spec that leaves transpilers falling 
> into the tarpit, if we can avoid it.
Semantics of private-class syntax hasn't been agreed on, so it's hard to 
say if transpilers would have a hard time with the eventually-agreed 
semantics, but Mark's desugaring with WeakMaps could work, couldn't it?

David


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