Lambda the Ultimate

PiDuce is a concurrent, distributed language intended for experimenting emerging Web Services technologies. PiDuce can be used as a target language for compilers and processors of business languages such as BizTalk and BPel...

PiDuce builds on solid theoretical foundations: it integrates the communication primitives of the Pi calculus, the synchronization patterns of the Join calculus, and an expressive type system that extends XML datatypes with first-class channels and that retains a notion of subtyping. PiDuce is
a type-safe language: well-typed process cannot fail.

PiDuce is implemented in C#. Source code and binaries are available for download.