From its home page (see below):

<blockquote>
[..] An open multi-language (see *(Combining Languages)) platform for interactive programming.

"<em>Multilanguage</em>" means that an application is constructed from source modules written in different languages. "<em>Interactive</em>" means that these modules are dynamically loaded into a shell, and can be used via your preferred language. Cross-language calls are part of the game.

*(Programming language)s currently supported are _(C|C Language), _(C++), _(Scheme), _(Prolog), and an OPS-style production system language.

[..]
</blockquote>

<ul class="implementations">
</li>_("Ravi home page"|http://www-prima.inrialpes.fr/Ravi/).
</ul>
