Daniel Janus’s blog
Posts in category: Clojure
Translating non-trivial codebases with Claude
I was wrong (or was I?)
In my last post, I stated:
I don’t think it’s [me writing about LLMs] likely to happen anytime soon: I prefer to write about things that I’m excited about.
I was wrong. And right at the same time. Here comes another post where LLMs play a prominent role.
No, really, you can’t branch Datomic from the past
(and what you can do instead)
I have a love-hate relationship with Datomic. Datomic is a Clojure-based database based on a record of immutable facts; this post assumes a passing familiarity with it – if you haven’t yet, I highly recommend checking it out, it’s enlightening even if you end up not using it.
Double, double toil and trouble
or, Corner-Cases of Comparing Clojure Numbers
Let’s talk about Clojure.
In Clojure, comparing two numbers can throw an exception.
Check this out:
(< 1/4 0.5M)
;=> true ; as expected
(< 1/3 0.5M)
; Execution error (ArithmeticException) at java.math.BigDecimal/divide (BigDecimal.java:1783).
; Non-terminating decimal expansion; no exact representable decimal result.
Lossy CSS compression for fun and loss (or profit)
What
Late last year, I had an idea that’s been steadily brewing in my head. I’ve found myself with some free time recently (it coincided with vacation, go figure), and I’ve hacked together some proof-of-concept code. Whether or not it is actually proving the concept I’m not sure, but the results are somewhat interesting, and I believe the idea is novel (I haven’t found any other implementation in the wild). So it’s at least worthy of a blog post.
My mental model of transducers
Intro
I’ve been programming in Clojure for a long time, but I haven’t been using transducers much. I learned to mechanically transform (into [] (map f coll)) to (into [] (map f) coll) for a slight performance gain, but not much beyond that. Recently, however, I’ve found myself refactoring transducers-based code at work, which prompted me to get back to speed.
Testing a compiler that can’t even print stuff out
I’m enjoying a week-long vacation. In addition to other vacationy things (a trip to Prague, yay!), I wanted to do some off-work programming Just For Fun™ and revisit one of my dormant pet projects, to see if I can make some progress.
I made a website to guess tomorrow’s number of COVID-19 cases, and here’s what happened
Before
It seems so obvious in hindsight. Here in Poland, people have been guessing it ever since the pandemic breakout: in private conversations, in random threads on social media, in comments under governmental information outlets. It seemed a matter of time before someone came up with something like this. In fact, on one Sunday evening in October, I found myself flabbergasted that apparently no one yet has.
Making of “Clojure as a dependency”
In my previous post, “Clojure as a dependency”, I’ve presented the results of some toy research on Clojure version numbers seen in the wild. I’m a big believer in reproducible research, so I’m making available a Git repo that contains code you can run yourself to reproduce these results. This post is an experience report from writing that code.
Clojure as a dependency
I have a shameful confession to make: I have long neglected an open-source library that I maintain, clj-tagsoup.
This would have been less of an issue, but this is my second-most-starred project on GitHub. Granted, I don’t feel a need for it anymore, but apparently people do. I wish I had spent some time reviewing and merging the incoming PRs.
Indenting cond forms
Indentation matters when reading Clojure code. It is the primary visual cue that helps the reader discern the code structure. Most Clojure code seen in the wild conforms to either the community style guide or the proposed simplified rules; the existing editors make it easy to reformat code to match them.