Machine readable specifications

Sam Tobin-Hochstadt samth at
Fri Mar 22 15:34:18 PDT 2013

On Fri, Mar 22, 2013 at 6:15 PM, Michael Dyck <jmdyck at> wrote:
> Andreas Rossberg wrote:
>> FWIW, there are at least two serious efforts of actually formalising
>> and mechanising the JavaScript language, i.e. its _semantics_, which
>> is a much more interesting endeavor.
> Could you give (or point me to) details of these projects?
> I've done some work along these lines (though I'm not sure it qualifies
> as "serious"), so I'm wondering if I'm just reinventing the work of
> others.

The two projects Andreas is referring to are:

S5 and LambdaJS, by Arjun Guha and others:
Another, unnamed semantics, by Ankur Taly and others:

S5, which covers (almost) all of ES5, is still under development, and
passes a large portion of Test262.


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