Clojure on Thomas Cothran

Pavlov for the Web

Fri, 17 Apr 2026 00:00:00 +0000

Pavlov brings behavioral programming to web development

Avoid with-redefs in tests

Mon, 07 Apr 2025 00:00:00 +0000

The use of with-redefs in tests indicates a poor understanding of good testing practices

Top-Down Imperative Clojure Architectures

Mon, 22 Jul 2024 00:00:00 +0000

When I first became interested in functional programming, a more experienced engineer told me: “you know functional programming doesn’t really amount to much more than procedural programming.” As I insisted on the benefits of map, filter and reduce, he simply shook his head. “You’re thinking in the small. Go look at a large real-world application.”

It took some time for me to see what he meant. My preferred language, Clojure, is a functional language. But too often it is used to build top-down, imperative applications. This negates the value proposition of functional programming: isolating side effects, local reasoning, and system composition.

MPAs vs SPAs: The False Dichotomy

Sun, 28 Jan 2024 00:00:00 +0000

This is the second post in the series “Have Clojure UIs Taken the Wrong Path?”. The first post is here.

How do we choose between building an application using a hypermedia approach versus the client-side SPA? This post won’t answer that question. But it will say how not to make that choice.

A common heuristic is the spectrum that stretches between old fashioned “Multi Page Apps” (MPAs) for basic use cases, to Single Page Applications for rich client interactivity.

Have Clojure UIs Taken the Wrong Path? Part 1

Fri, 24 Nov 2023 00:00:00 +0000

The Clojure community has focused on React-based solutions for complex front-end clients such as Reagent, Rum, Om, Re-frame, and Fulcro.

For all their differences, they follow a very similar architecture, making heavy use of client-side state and using RPC for client-server communication. We will call this the “React+” approach.

But is this the right choice?

I will suggest the answer may be negative. My suspicion is that as web UI libraries advance, the problems they solve are not essential. Rather, the problems are accidental; they are generated by the React+ architecture.

The Wrong Kind of Readability

Sun, 05 Nov 2023 00:00:00 +0000

Andy Hunt and Dave Thomas tell us: 'it’s critical that you write code that is readable and easy to reason about.' This seems uncontroversial; it is the rare point on which software engineers typically agree. Or do they?

Brittle Clojure: Creating Legacy Clojure Systems

Sun, 23 Jul 2023 00:00:00 +0000

Avoid writing brittle Clojure with tactics for flexibility and robustness.