REPLs All The Way Up: A Rubric For Better Feedback Loops

GOTO Chicago 2023

We all know that the key to successful software development is iteration and feedback loops, whether that takes the form of the red-green-refactor cycle, or agile project planning. But not all feedback is equally valuable.

I propose a novel archetype for virtuous feedback cycles: the humble Read-Eval-Print-Loop (REPL). In this talk, we’ll talk about the history of REPLs and how they revolutionized early programming environments. We’ll examine the evolution of iterative feedback in software development processes, through the lens of “REPL nature”. We’ll talk about “scientific” processes, and why the proverbial theory/experiment cycle is not sufficient for good science or graceful software development.

Finally, we’ll explore what makes for better feedback loops at every level of the software process, from building algorithms up to business intelligence. You’ll leave with a new rubric for evaluating and improving the iterative circles you work in every day.