Ask-Elle: A Haskell Tutor

Abstract

Ask-Elle is a tutor for learning the higher-order, strongly-typed func-tional programming language Haskell. It supports the stepwise development of Haskell programs by verifying the correctness of incomplete programs, and by providing hints. Teachers can add programming exercises to Ask-Elle by provid-ing a task description for the exercise, one or more model solutions, and properties that a solution should satisfy. A teacher can annotate properties and model solu-tions with feedback messages, and can specify the amount of flexibility allowed in student solutions. This paper presents the design of Ask-Elle, shows the results of several ex-periments we performed with Ask-Elle, and discusses the technology used for the development of Ask-Elle.