FSM Builder: A Tool for Writing Autograded Finite Automata Questions

TL;DR

FSM Builder is an interactive pedagogical tool that helps students learn finite automata by constructing DFAs and NFAs with graphical feedback, improving understanding and engagement in computing theory courses.

Contribution

The paper introduces FSM Builder, a scalable, flexible tool for constructing automata with personalized feedback, enhancing existing educational methods.

Findings

Students found the interface and feedback useful.

The tool was successfully used in multiple large courses.

It offers greater flexibility and scalability than previous tools.

Abstract

Deterministic and nondeterministic finite automata (DFAs and NFAs) are abstract models of computation commonly taught in introductory computing theory courses. These models have important applications (such as fast regular expression matching), and are used to introduce formal language theory. Undergraduate students often struggle with understanding these models at first, due to the level of abstraction. As a result, various pedagogical tools have been developed to allow students to practice with these models. We introduce the FSM Builder, a new pedagogical tool enabling students to practice constructing DFAs and NFAs with a graphical editor, giving personalized feedback and partial credit. The algorithms used for generating these are heavily inspired by previous works. The key advantages to its competitors are greater flexibility and scalability. This is because the FSM Builder is implemented using efficient algorithms from an open source package, allowing for easy extension and question creation. We discuss the implementation of the tool, how it stands out from previous tools, and takeaways from experiences of using the tool in multiple large courses. Survey results indicate the interface and feedback provided by the tool were useful to students.