Historically?  It still is!  :)<p>I think VLISP is, as well.  VLISP (not the French one from the 80s, the other one, though the French one was interesting in its own right [1]), was a verified Scheme implementation written in a verified version of Pre-Scheme.  Sweet research project, but I haven&#x27;t seen any public releases of it :&#x2F;<p>There are some papers about both here:  <a href="http:&#x2F;&#x2F;library.readscheme.org&#x2F;page8.html" rel="nofollow">http:&#x2F;&#x2F;library.readscheme.org&#x2F;page8.html</a><p>[1]:  <a href="http:&#x2F;&#x2F;www.artinfo-musinfo.org&#x2F;en&#x2F;issues&#x2F;vlisp&#x2F;index.html" rel="nofollow">http:&#x2F;&#x2F;www.artinfo-musinfo.org&#x2F;en&#x2F;issues&#x2F;vlisp&#x2F;index.html</a><p>VLISP was a precursor to Le-Lisp [2], which was massively popular and influential in Europe, and could run faster on commodity hardware than Lisp Machine Lisp on the Symbolics 3600.<p>[2]:  <a href="http:&#x2F;&#x2F;lelisp.org&#x2F;" rel="nofollow">http:&#x2F;&#x2F;lelisp.org&#x2F;</a>  (under construction, but with some useful links for the time being).<p>France was actually a hotbed of Lisp across the pond and, along with the UK, pretty invested in a European standard for Lisp, first EuLisp (which was an excellent language but somehow flopped unfortunately) and ISLISP (an ISO standard that&#x27;s not so excellent -- basically a crippled version of Common Lisp -- and also pretty much flopped).  I&#x27;ve been in talks with some of the Le-Lisp guys about the possibility of open-sourcing Le-Lisp now that it&#x27;s no longer commercially viable -- fingers crossed!  :)<p>P.S., if anyone from INRIA happens to be reading this:  pretty please??  Jérôme agrees!  :)