Designing the whyline

TLDR

Debugging is a costly, common activity, largely because existing tools fail to support its inquisitive nature. The Whyline is a prototype Interrogative Debugging interface for the Alice environment that visualizes answers as runtime events directly relevant to the programmer’s question. User tests comparing identical debugging scenarios with and without the Whyline showed that the Whyline reduced debugging time by nearly eightfold and enabled programmers to complete 40 % more tasks.

Abstract

Debugging is still among the most common and costly of programming activities. One reason is that current debugging tools do not directly support the inquisitive nature of the activity. Interrogative Debugging is a new debugging paradigm in which programmers can ask why did and even why didn't questions directly about their program's runtime failures. The Whyline is a prototype Interrogative Debugging interface for the Alice programming environment that visualizes answers in terms of runtime events directly relevant to a programmer's question. Comparisons of identical debugging scenarios from user tests with and without the Whyline showed that the Whyline reduced debugging time by nearly a factor of 8, and helped programmers complete 40% more tasks.