Check out Jsonnet and HOCON.<p>Jsonnet:
<a href="http://google.github.io/jsonnet/doc/" rel="nofollow">http://google.github.io/jsonnet/doc/</a><p>HOCON:
<a href="https://github.com/typesafehub/config/blob/master/HOCON.md" rel="nofollow">https://github.com/typesafehub/config/blob/master/HOCON.md</a>