Opa

A one-size-fits-all environment for Web application writing. It apparently subsumes the database, server, and both server-side and client-side programming into one big programming language. I'm pretty sure I've linked it before, but just in case: Opa.

It might be instructive to work out their examples in Decl.

Opa's central thesis is that polyglot programming suffers from impedance mismatches that slow down any programming effort. I guess my own Decl-based WWW::Publisher's answer to that isn't to eliminate the polyglossia, but to provide some kind of macro-based assistance to make sure your polyglossia has a solid framework to work in.