A unified semantics for future Erlang

Abstract

The formal semantics of Erlang is a bit too complicated to be easily understandable. Much of this complication stems from the desire to accurately model the current implementations (Erlang/OTP R11-R14), which include features (and optimizations) developed during more than two decades. The result is a two-tier semantics where systems, and in particular messages, behave differently in a local and a distributed setting. With the introduction of multi-core hardware, multiple run-queues and efficient SMP support, the boundary between local and distributed is diffuse and should ultimately be removed. In this paper we develop a new, much cleaner semantics, for such future implementations of Erlang. We hope that this paper can stimulate some much needed debate regarding a number of poorly understood features of current and future implementations of Erlang.