Hyperflow: A Visual Programming Language for Pen Computers
This paper presents the design philosophy of the Hyperflow visual programming languauge. It also gives an overview of its semantic model. The primary purpose of language is to provide a user interface for a pen-based multimedia computer system designed for school children. Yet it is versatile enough to be used as a system programming language. The concept of visually interactive process, vip in short, is introduced as the fundamental element of the semantics. Vips communicate with each other through exchange of signals, either discrete or continuous. Each vip communicates with the user through its own interface box by displaying on the box information about the vip and by receiving information pen-scribed on the box. There are four different communciation modes: mailing, posting, channeling, and broadcasting. Mailing and posting are for discrete signals and channeling and broadcasting are for continuous signals. Simple Hyperflow programs are given for the purpose of illustration, including a Hyperflow specification for the Line-Clock device driver.