A Tool to Assist the Compiler Construction Instructor in Checking the Equivalence of Specifications Based on Regular Expressions

This paper presents CheRegES (CHEcking REGular Expression-based Specifications), a tool that assists the Compiler Construction instructor in checking the equivalence of computer language lexical specifications based on regular expressions. The tool allows the comparison of a reference specification, provided by the instructor, with the specification proposed by the student. As a result, the tool can report that: (i) both specifications are equivalent (and, therefore, the specification proposed by the student can be considered correct); (ii) there are discrepancies between the specification proposed by the student and the one provided by the instructor (and, therefore, the specification proposed by the student can be considered incorrect); or (iii) the result of the comparison is inconclusive. Also, in case discrepancies are discovered, the tool provides sentences that allow differentiation between the two specifications, and that help the instructor to diagnose the problems underlying the student’s specification. The paper motivates the need for the tool, describes its functionality, briefly summarizes its internals, and presents a preliminary evaluation of the tool that makes the usefulness of CheRegES as a tool to support assessment in Compiler Construction courses apparent.