Dependent Session Types

TL;DR

This paper introduces the first formulation of dependent session types, combining linearity and duality guarantees without runtime checks, and demonstrates a practical implementation in ATS compiling to Erlang/Elixir.

Contribution

It presents a novel dependent session type system that ensures communication correctness without runtime overhead, suitable for practical distributed programming.

Findings

First dependent session type system with no runtime checks

Implementation in ATS compiling to Erlang/Elixir

Guarantees linearity and duality in communication protocols

Abstract

Session types offer a type-based discipline for enforcing communication protocols in distributed programming. We have previously formalized simple session types in the setting of multi-threaded $\lambda$-calculus with linear types. In this work, we build upon our earlier work by presenting a form of dependent session types (of DML-style). The type system we formulate provides linearity and duality guarantees with no need for any runtime checks or special encodings. Our formulation of dependent session types is the first of its kind, and it is particularly suitable for practical implementation. As an example, we describe one implementation written in ATS that compiles to an Erlang/Elixir back-end.