Revisiting Type-Driven Design of Communicating Systems

I am giving a talk today about implementing global session types as an EDSL within Idris.

The abstract is:

Communication protocols are a cornerstone of modern system design. However, there is a disconnect between the tooling used to design, implement and reason about these protocols and their implementations. Session Types offer a typing discipline that helps resolve this difference by allowing protocol specifications to be used during type-checking, ensuring that implementations adhere to a given specification. Session Type implementations are, however, limited in their expressiveness in protocol design and implementation.

In previous (unpublished) joint work with Edwin Brady, we investigated how to realise a Multi-Party Session-Types inspired language within the dependently typed language Idris. Our work allowed rich protocol descriptions to be described in, and intrinsicly linked, to the protocol implementation: communicating systems were correct-by-construction. A major limitation of our work was that we could not reason competently about value-dependent messages. These are messages that rely upon values previously seen in the protocol.

Recently, I have had a chance to revisit this work and found a interesting solution using /Resource Dependent EDSLs/ to describe value dependent session descriptions. In this talk I will describe the underlying construction techniques employed; demonstrate the ability of our new session description language to describe interesting protocols; and discuss future directions and re-visitations of my previous work.

Slides are not available.