Declarative Game Programming: Distilled Tutorial

TL;DR: This tutorial shows how this can be achieved through Functional Reactive Programming (FRP) by implementing the high-level parts of a 2D game akin to the classical game Breakout by using the Haskell-embedded FRP implementation Yampa and bindings to SDL.

Abstract: Video games are usually not programmed very declaratively. There are a number of reasons for this, from low-level efficiency concerns, via the nature of commonly employed programming languages, libraries, and frameworks, to the conceptual nature of such games, with state and effects being omnipresent. However, by structuring games in terms of time-varying values and transformations on such values, it is possible to design and implement video games in a more declarative way. This tutorial shows how this can be achieved through Functional Reactive Programming (FRP) by implementing the high-level parts of a 2D game akin to the classical game Breakout. The tutorial uses the Haskell-embedded FRP implementation Yampa and bindings to SDL (Simple DirectMedia Layer) to obtain game play and visual standards typical of the 2D genre; for example, as seen in many currently popular games for smartphones and tablets.