Snapdown: A Text-Based Snapshot Diagram Language for Programming Education

Abstract

Snapshot diagrams, which visualize in-memory program state, are frequently used in programming education to demonstrate new concepts and help students develop a better understanding of program functionality. This thesis introduces Snapdown, a textual language for drawing snapshot diagrams, designed for use by both students and instructors of programming courses. Snapdown is designed with an emphasis on learnability and simplicity: both to be picked up by students in a classroom setting in a matter of minutes, and to enable creation and maintenance of diagrams in instructional content with minimal overhead. I introduce several use cases of Snapdown and describe the design and features of its textual language. I also describe a deployment of Snapdown during two semesters of emergency remote teaching in MIT software engineering course 6.031 Software Construction, in which students used it to complete pre-class reading exercises and in-class collaborative exercises. Finally, I demonstrate that Snapdown is generally applicable by using it to replicate over 100 diagrams from introductory- and intermediate-level courses at a variety of institutions.