Session Typing for a Featherweight Erlang

Dimitris Mostrous, University of Lisbon, Portugal

(Joint work with Vasco Vasconcelos)

As software tends to be increasingly concurrent, the paradigm of message passing is becoming more prominent in computing. The language Erlang offers an intuitive and industry-tested implementation of process-oriented programming, combining pattern-matching with message mailboxes, resulting in concise, elegant programs. However, it lacks a successful static verification mechanism that ensures safety and determinism of communications with respect to well-defined specifications. We present a session typing system for a featherweight Erlang calculus that encompasses the main communication abilities of the language. In this system, structured types are used to govern the interaction of Erlang processes, ensuring that their behaviour is safe with respect to a defined protocol. The expected properties of subject reduction and type safety are established.