Visual programming-in-the-large versus visual programming-in-the-small

Visual programming research has largely focused on the issues of visual programming-in-the-small. However, entirely different concerns arise when one is programming-in-the-large. We present a visual software engineering environment that allows users to construct visually programs consisting of hierarchically organized networks of components that process streams of arbitrary objects. We discuss the problems that occur when trying to construct systems consisting of thousands of interconnected components, examine how this environment deals with some of the problems specific to visual programming-in-the-large, and show why our initial solutions failed to scale successfully. Finally, we argue that a single visual mechanism called “zooming” addresses these scaling problems and, when suitably augmented, can also support automatic component discovery and intelligent error correction