Elm: Concurrent FRP for Functional GUIs

Graphical user interfaces (GUIs) mediate almost all of our interactions with computers, whether it is through web pages, phone apps, or desktop applications. Functional Reactive Programming (FRP) is a promising approach to GUI design. This thesis presents Elm, a concurrent FRP language focused on easily creating responsive GUIs. Elm has two major features: (1) purely functional graphical layout and (2) support for Concurrent FRP. Purely functional graphical layout is a high level framework for working with complex visual components. It makes it quick and easy to create and combine text, images, and video into rich multimedia displays. Concurrent FRP solves some of FRP’s long-standing efficiency problems: global delays and needless recomputation. Together, Elm’s two major features simplify the complicated task of creating responsive and usable graphical user interfaces. This thesis also includes a fully functional compiler for Elm, available at elm-lang.org. This site includes an interactive code editor that allows you to write and compile Elm programs online with no download or install.