TyCO - Typed Concurrent Objects

TyCO - Typed Concurrent Objects, is an implicitly typed polymorphic concurrent language based on an extension of the asynchronous pi-calculus featuring first class objects, asynchronous messages and process definitions. Definitions allow, among other things, for object classes to be modeled. A type system assigns monomorphic types to variables and polymorphic types to definition identifiers. TyCO provides a very clean model for a concurrent object-based language which combines the benefits of the formal framework of process calculi with the characteristics of Hewitt's actor system.

There are several reasons why you should want to try TyCO, namely: for programming in the pi-calculus with primitive objects (and no obligation to specify types at identifier declaration), for teaching purposes and to study language design and implementation (by experimenting with the code for the compiler and for the virtual machine).