How I would do the “Bowling Game Kata” in Haskell today

By Tom Moertel Posted on July 30, 2026 Tags: code, comments, clean code, good code, source code, haskell, kata, bowling, tdd Recently, Philip Schwarz from fpilluminated.org wrote to let me know about a new slide deck he had published: The Bowling Game - From Imperative to Functional Programming - Part 1. In the deck, he revisits the “Bowling Game Kata” and summarizes some of the discussion (controversy?) spurred by this exercise over the last two decades. Philip tells this story in a rather clever fashion that blends code, graphics, and comic-book storytelling techniques, so consider checking out the deck. Anyway, he wrote in particular to kindly let me know that one of the code examples he examines is from my blog, way back when I was learning Haskell in 2006: The Bowling Game Kata in Haskell. This got me thinking about how I might write this code today. So I revised the code, and here it is. (Be sure to read my rationale for each change, which follows the code.) {- My solution to…