Broadcast-based communication in a programming environment for novices

Abstract

This thesis proposes a model to make communication and processes in an object-oriented language accessible to novice programmers. For my thesis work, I developed a broadcast communication framework in the context of Scratch, an object-based programming language intended for children and being developed at the MIT Media Laboratory. Objects in this framework can broadcast events, which trigger other objects to start new processes. In this document, I identify the basic functionality required to support object communication in such a broadcast model, I describe my implementation of that functionality, and I consider the merits of various user interface metaphors to make these features accessible to novices. Finally, I compare the event broadcasting in this model with the use of procedures in more traditional programming languages, and raise questions as to whether the broadcast model's event handlers should supplement or supplant procedures in a beginner's programming language.