A Java-based environment for teaching programming language concepts

The authors describe the SDE visual environment for the study of the semantics of programming languages. SDE supports the abstract machine called SIMPLESEM which is used to define the operational semantics of programming languages in a widely-used textbook on programming languages. By basing the environment on the World-wide Web infrastructure, the environment is immediately available to students and instructors around the globe. SDE enhances the student's learning by simulating and visualizing abstract concepts of semantics. Such visualization environments are invaluable in the study of abstract subjects. SDE is currently being used in several university courses in different countries. The authors describe the environment's architecture and capabilities and review some of their experiences in developing the environment.