Lambda the Ultimate

Acute: high-level programming language design for distributed computation

This work is exploring the design space of high-level languages for distributed computation, focussing on typing, naming, and version change. We have designed, formally specified and implemented an experimental language, Acute. This extends an OCaml core to support distributed development, deployment, and execution, allowing type-safe interaction between separately-built programs. It is expressive enough to enable a wide variety of distributed infrastructure layers to be written as simple library code above the byte-string network and persistent store primitives, disentangling the language runtime from communication.

This requires a synthesis of novel and existing features:

• type-safe interaction between programs, with marshal and unmarshal primitives;
• dynamic loading and controlled rebinding to local resources;
• modules and abstract types with abstraction boundaries that are respected by interaction;
• global names, generated either freshly or based on module hashes: at the type level, as runtime names for abstract types; and at the term level, as channel names and other interaction handles;
• versions and version constraints, integrated with type identity;
• local concurrency and thread thunkification; and
• second-order polymorphism with a namecase construct.

The language design deals with the interplay among these features and the core. The semantic definition tracks abstraction boundaries, global names, and hashes throughout compilation and execution, but still admits an efficient implementation strategy.