Reposted from ES4 discussion (about ECMAScript):

 
 >  We seem to have chosen ML (OCaml with call/cc, probably) as the meta-
 >  language for the ES4 spec.  This is hot of the presses, but it looks 
 >  like the right choice, and any change that moves away from it will 
 >  take unlikely effort and a better candidate language.  We were faced 
 >  with the arduous task of inventing our own sound meta-language, and 
 >  it started looking like ML with customizations.

 >  This means we will have a reference implementation, with all the 
 >  software engineering overhead that implies.  But it will be an 
 >  implementation whose goal is clarity and soundness, not space or time 
 >  performance.  And with some work, as Cormac Flanagan points out, the 
 >  reference code (or probably a subset of it) could be used with Coq to 
 >  do automated proofs.

 >  We will make the reference implementation available in due course, as 
 >  open source.   We will welcome contributors (Hi, Nicolas! ;-).

I think it's quite interesting how it influences our attempt to write 
down JS interpreter.

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