Strong agree. School had me writing stuff myself on the order of a few KLOC at most, and maybe collaborating with a "group" in which at most 2 people actually did anything. What little exposure I got to reading a large codebase I didn't write, was all in personal projects trying to mod open source video games. I'm sure some people had more extensive experiences but that was my bachelor's.

First job had me using a programming language I wasn't super familiar with and trying to add a feature to a codebase 100s of KLOC, all written by other people. Definitely a sink-or-swim moment. My skills of reading and navigating the dreaded Other People's Code were all honed over the next dozen years.

That being said AI is a lot better at reading code than I am, as demonstrated by its ability to find incredibly subtle bugs in huge codebases. So I'm not even sure those code reading skills are all that useful now. When I have to review somebody else's code I get more mileage from pointing an AI at it and asking targeted questions like "how does this handle when a Foo's approval is revoked" than reading it myself line-by-line. I'm not saying I never use those reading skills but the ability to get the big picture, chase down deep callback chains, know where to look... those skills are likely to atrophy.

It's like using GPS vs. knowing the roads as well as a cabbie. GPS gets you pretty damn far for zero effort.

Yeah I agree that reading is a different skill from writing, especially reading someone else's code - I think doing code reviews is a great and valuable skill that should be taught alongside but separately from writing code. Can you reason about someone else's code without immediately rewriting it or jumping to "Well I would have written it differently"?

It's an important skill to learn, as a lot of software developers enter the market as "selfish", thinking they should understand and / or own all code, and if there's too much code or too many other people, they will advocate for microservices so they can once again own their slice of code.

But that's coding; software engineering is coding at scale, over time, and for the last two you need a different (albeit complementary) skillset of both hard and soft skills (hard skills being reading / understanding / reasoning about code, soft skills being letting go of your own ego and giving constructive feedback)

Reading code was always much harder than writing it and it's certainly the root of many NIH syndrome disasters. Writing helps, but you're right that these are two seperate and related skills.

Reading code is very hard because you have to build a mental model from code that others wrote. You’re trying to understand what they wrote, the intent behind that, and what’s wrong or missing - that’s just a fundamentally hard thing.

But building mental models based on data and communications from others is one of the most valuable problem solving and communication skills there is in business, precisely what Carson is getting at in his essay.

Don't think you can be a mature developer unless you can fluently read code. I tell everyone learning to code that reading code is equally important. In our world of AI tools reading code is turning out to be a key skill.

> It certainly feels like its possible to learn to write it without learning to read it.

There's a perhaps subtle difference between possible and viable.

Would you mind sharing some of the insights you gained on reading code? It could be useful for the more junior of us!

I don’t think so. I strongly believe that writing and reading is pretty much the same, because they are strongly related to thinking. They are even secondary to the latter. I often interacted with juniors and other colleagues and those that do have issue with writing and reading often struggle with formalized thinking.

Taking a problem or a wanted behavior and dissecting it down to logical manipulation is hard for those people. They can go down one or two layers but then they got lost while building the necessary abstraction. You can observe it pretty much in real time as they’re losing track of assumptions for the current context. Thinking that way is a skill and once you can do it, reading and writing code is pretty much effortless.

Both learning to write and learning to read is merely a proxy of learning to think. Doing one while not doing the other is handicapping yourself for no reason.