Visual AgenTalk: Anatomy of a Low Threshold, High Ceiling End User Programming Environment

: Typical approaches to end user programming involve design trade-offs between ease of use and expressiveness End user programming environments are either easy to use and not very expressive (low threshold/low ceiling) or more difficult to use but more powerful (high threshold/high ceiling). We propose the development of end user programming environments that are both low threshold and high ceiling by combining a collection of mechanisms that address the issues of program comprehensibility, language tailorability, and interactive multimodality. In this paper, we describe the layered anatomy of a low threshold/high ceiling environment that is usable by both end users and language designers. We then illustrate our theory with a description of a new low threshold/high ceiling end user programming environment called Visual AgenTalk.