Model-View-Update-Communicate: Session Types meet the Elm Architecture [article]

Simon Fowler
2020 arXiv   pre-print
Session types are a type discipline for communication channel endpoints which allow conformance to protocols to be checked statically. Safely implementing session types requires linearity, usually in the form of a linear type system. Unfortunately, linear typing is difficult to integrate with graphical user interfaces (GUIs), and to date most programs using session types are command line applications. In this paper, we propose the first principled integration of session typing and GUI
more » ... t by building upon the Model-View-Update (MVU) architecture, pioneered by the Elm programming language. We introduce λ_MVU, the first formal model of the MVU architecture, and prove it sound. By extending λ_MVU with commands as found in Elm, along with linearity and model transitions, we show the first formal integration of session typing and GUI programming. We implement our approach in the Links web programming language, and show examples including a two-factor authentication workflow and multi-room chat server.
arXiv:1910.11108v3 fatcat:4fnbw5icibatfatxbav26hou4i