The Programming Exercise Markup Language: Towards Reducing the Effort Needed to Use Automated Grading Tools

Automated programming assignment grading tools have become integral to CS courses at introductory as well as advanced levels. However such tools have their own custom approaches to setting up assignments and describing how solutions should be tested, requiring instructors to make a significant learning investment to begin using a new tool. In addition, differences between tools mean that initial investment must be repeated when switching tools or adding a new one. Worse still, tool-specific strategies further reduce the ability of educators to share and reuse their assignments. This paper describes an early experiences with PEML, the Programming Exercise Markup Language, which provides an easy to use, instructor friendly approach for writing programming assignments. Unlike tool-oriented data interchange formats, PEML is designed to provide a human friendly authoring format that has been developed to be intuitive, expressive and not be a technological or notational barrier to instructors. We describe the design and implementation of PEML, both as a programming library and also a public-access web microservice that provides full parsing and rendering capabilities for easy integration into any tools or scripting libraries. We also describe experiences using PEML to describe a full range of programming assignments, laboratory exercises, and small coding questions of varying complexity in demonstrating the practicality of the notation. The aim is to develop PEML as a community resource to reduce the barriers to entry for automated assignment tools while widening the scope of programming assignment sharing and reuse across courses and institutions.