PaSe: An Extensible and Inspectable DSL for Micro-Animations

This paper presents PaSe, an extensible and inspectable DSL embedded in Haskell for expressing micro-animations. The philosophy of PaSe is to compose animations based on sequential and parallel composition of smaller animations. This differs from other animation libraries that focus more on sequential composition and have only limited forms of parallel composition. To provide similar flexibility as other animation libraries, PaSe features extensibility of operations and inspectability of animations. We present the features of PaSe with a to-do list application, discuss the PaSe implementation, and argue that the callback style of extensibility is detrimental for correctly combining PaSe features. We contrast with the GreenSock Animation Platform, a professional-grade and widely used JavaScript animation library, to illustrate this point.