Walker: Automated Assessment of Haskell Code using Syntax Tree Analysis

Programming educators often require students to use specific language features to ensure that they meet the educational goals. Verifying such requirements can be very time-consuming for teaching staff. This research investigates the usage of (static) syntax tree analysis to automatically validate the presence of required language constructs in Haskell programs. This paper shows the effectiveness of this approach by testing a prototype written in Haskell (named Walker) on submissions by students, and discusses the different techniques used for traversing the syntax tree when validating the requirements. The results show the approach to be highly accurate, only showing weaknesses when evaluating student-defined types or deviating function names.