This paper describes the development ofEvaluators, an educational system oriented to the generation of different kinds ofinteractive simulations for introductory Compiler Construction courses in Computer Science and Computer Engineeringdegrees.Evaluatorsconsists of three main instructor-oriented components: (i) an authoring tool that instructors use toauthor collections of exercises concerning attribute grammars, which are a basic formalism for describing languageprocessing tasks, (ii) a generator, which is able to automatically generate different kinds of interactive simulations fromthesebatteries of exercises,and(iii) ananalytic tool used toassess student performancebyanalyzingthe logs recorded whilestudents use the simulations. The underlying development principles behindEvaluatorspromote: (i) a generative approachto the production of interactive simulations from high-level descriptions of exercises, and (ii) a user-centered approach,according to which the system was iteratively enhanced according to the continuous assessment of the successive versionsof the system with instructors and students. In this way, these principles illustrate a development approach centered on theconstruction of generative educational software (instead of on the construction of individual applications) and guided by acontinuous assessment of this software with end users (not only students, but also instructors), which can be meaningfullyextrapolated to other fields of Engineering Education.