Foundations of Session Types: 10 Years Later

Abstract

We were thrilled to know that our PPDP’09 paper “Foundations of Session Types” [10] was selected for the PPDP Most Influential Paper 10-Year Award. Just moments after being notified of this, we couldn’t help looking at the works that cited—and in some cases were inspired by—our own. The result is the following short note, in which we recollect the main ideas behind our own work and the related ones that followed. The tight gap between the award notification and the deadline for the production of the PPDP’19 proceedings prevent us from providing an exhaustive survey of the related literature and we apologize in advance for the conciseness of our report and any relevant omission. Fortunately, there exist recent surveys [2, 4, 14, 21] that may help the interested readers orient themselves into the vast literature of session types as a whole. Sessions and session types have proved to be extremely successful concepts for the structuring and the analysis of communications in distributed systems. A session is a private communication channel through which participating processes, using the so-called session endpoints, can communicate without interference from other processes. This privacy property of sessions enables the modular reasoning on complex systems, whereby each session is treated— and typed—in isolation. Thus, it is relatively easy to conceive type