The Apache Clownfish symbiotic object system is an alternative to the &quot;universal runtime&quot; approach.  It is a library rather than a platform.<p>Instead of trying to provide a <i>superset</i> of semantics which encompasses all languages, it provides a single runtime which supports a <i>subset</i> of features, which then lives inside the &quot;host&quot; language environment.<p><a href="https:&#x2F;&#x2F;github.com&#x2F;apache&#x2F;lucy-clownfish" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;apache&#x2F;lucy-clownfish</a>