VIPER, a Student-Friendly Visual Interpreter of Pascal

We introduce VIPER, a visual interpreter of Pascal, designed to help both the teachers and the students of an introductory programming course. The main innovation of VIPER is the ability to display typically encountered data structures (e.g. trees, lists) in an intuitive way. This, and other usability improvements, have been designed specifically to meet the needs of future users. The interpreter is aimed mostly at small scaleprogramming exercises, and lets the user edit and run portions of code step-by-step with all the needed values being displayed in a suitable manner.