Complementing the Digital Programming Tutor Ask-Elle with Program Synthesis

Abstract

Practising is a part of learning how to program. Usually, teachers help students with this, but digital alternatives are available. Ask-Elle is such an alternative, developed for teaching the functional programming language Haskell. Students can submit partial solutions to exercises and will receive feedback from Ask-Elle. However, it has some limitations when dealing with partial solutions that diverge from the structure of its reference solutions. We present a proof of concept to complement Ask-Elle (called thupy) that aims to handle solutions where students do not follow the structure of the reference solutions from Ask-Elle. We use program synthesis to generate a suggested next step for a student, with more focus on the behaviour rather than the structure of the reference solutions. Our results show that this is a promising idea. Evaluating thupy on a dataset gathered from Ask-Elle, we manage to provide feedback on 21% of student solution where Ask-Elle cannot, and 35% of solutions where it can. We measure an average runtime of 3 seconds, which is an acceptable amount of time to wait for feedback.