Hydro is an independent implementation of ICE, the object-oriented RPC protocol by ZeroC, for the O'Caml programming language. Hydro (like ICE) allows you to bridge language barriers by letting components written in different programming languages communicate with each other. ZeroC's ICE product currently includes implementations for C++, Java, C#, Python, Ruby, VB, and PHP. Hydro adds support for O'Caml. Hydro includes an asynchronous runtime and a generator called hydrogen.