A higher-order functional programming language, written in Ocaml, which compiles to and integrates with (embeds in) C++. The type system is similar to ML's, while the syntax is mostly similar to that of C++. The language includes a powerful macro-expansion facility, a module system, and the ability to use inlined C++ code and types as primitives.

It supports ultra-lightweight threading and message-passing through compilation to continuations. The environment is also garbage-collected and provides standard bindings and binding-creation support for C and C++.