Pedal - An Infrastructure for Automated Feedback Systems.

This paper describes Pedal, an innovative approach to the automated creation of feedback given to students in programming classes. Pedal is so named because it supports the PEDAgogical goals of instructors and is an expandable Library of components motivated by these goals. Pedal currently comes with components for type inferencing, flow analysis, pattern matching, and unit testing to provide an instructor with a rich set of resources to use in authoring and prioritizing feedback. The larger vision is the loosely-coupled architecture whose components can be readily expanded or replaced. The Pedal library components are motivated by a study of contemporary automated feedback systems and our own experience. Pedal's components are described and examples are given of Pedal-based feedback from three different introductory classes at two different universities. The integration of Pedal into several programming and autograding environments is briefly described.