Adjoint Reactive GUI Programming

by Dr. Neel Krishnaswami

• When: Friday, 10/9/2021, between 1pm and 2pm (5pm-6pm UTC), EST
• Where: Zoom; Outside guests please RSVP by emailing Harley Eades
• YouTube Stream/Recording: https://youtu.be/Jp5DsOXs6fE

Abstract

Most interaction with a computer is done via a graphical user interface. Traditionally, these are implemented in an imperative fashion using shared mutable state and callbacks. This is efficient, but is also difficult to reason about and error prone. Functional Reactive Programming (FRP) provides an elegant alternative which allows GUIs to be designed in a declarative fashion. However, most FRP languages are synchronous and continually check for new data. This means that an FRP-style GUI will “wake up” on each program cycle. This is problematic for applications like text editors and browsers, where often nothing happens for extended periods of time, and we want the implementation to sleep until new data arrives. In this talk, I present an asynchronous FRP language for designing GUIs called λ𝖶𝗂𝖽𝗀𝖾𝗍. Our language provides a novel semantics for widgets, the building block of GUIs, which offers both a natural Curry–Howard logical interpretation and an efficient implementation strategy.