Usability Methods for Designing Programming Languages for Software Engineers

Programming language design requires making many usability-related design decisions. We explored using user-centered methods to make languages more effective for programmers. However, existing HCI methods expect iteration with appropriate users, who must learn to use the language to be evaluated. These methods were impractical to apply to programming languages: they have high iteration costs, programmers require significant learning time, and user performance has high variance. To address these problems, we adapted HCI methods to reduce iteration and training costs and designed tasks and analyses that mitigated the high variance. We evaluated the methods by using them to design two languages for professional developers. Glacier extends Java to enable programmers to express immutability properties effectively and easily. Obsidian is a language for blockchains that includes verification of critical safety properties. Summative usability studies showed that programmers were able to program effectively in both languages after short training periods.