Composing Haggis

Haggis is a purely-functional, multi-threaded user interface framework for composing interactive applications. It provides a compositional view of the world of user interface applications, applying to all aspects of the interface the principle of building a component from parts. Interactive components are viewed as virtual I/O devices that are composed together to make up complete applications. To fully support this style of programming, Haggis makes good use of the integral an extensible, modular and simple programming model for writing user interface applications at a high level of abstraction.

Two key ingredients that Haggis relies on to provide its compositional style are concurrency and monads, making it possible to write multi-threaded functional programs that interact with the Real World comfortably.