Comment by grayrest | Hacker News Reader

Comment by grayrest | Hacker News Reader

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If you're on a project every day and familiar with all the pieces, there's not a large advantage to static typing. Static typing allows people unfamiliar with the program to make changes and have a reasonably high degree of confidence that they got them right. This can be junior devs, people new to the project, you after 5 years away, or a project that's grown to the point where nobody knows all the pieces.

I'm not saying this as a die-hard static typing fan. I wrote Python for years, have written JS professionally most of my career, and spent 2 years writing Clojure professionally. I'm comfortable with dynamic languages. The Clojure codebase was the most stable I've been on (including typed languages) largely due to the senior team and excellent QA. The only problem I had with it was when business shifted from a subscription model to an a-la-carte model, which required manually reworking a LOT of maps to match the new requirements. This is considerably more painful in a dynamic language than it is in a static one.

There IS a downside to static typing in terms of verbosity. I've seen Java codebases where half the code was there basically because of the static typing. More advanced type systems do not suffer from that problem. I'm fine with OCaml / F# / Rust / Typescript.

Great points, thank you for sharing your experience.

Manual rework of maps seems like something that a good IDE or a small script should be able to automate, that is the point of Clojure being a data structure (EDN) after all - you can do stuff to the code as if it was data. Maybe there were specifics not allowing such sweeping changes, would love to hear more if you can share more about it.

I have a colleague which became 18 just a few days ago. He newer heard of Clojure(Script) or CSS before late last year and started actively learning it sometime after that. Jan is able to work on considerable amounts of code for our new landing page that will have some special interactive OrgPad embeds in it. He didn't have much difficulty navigating Clojure or our code base considering he did most of the work after school and on weekends basically as a learning exercise. Of course, he is getting solid guidance by the team. Our CTO Pavel has 20+ years of experience as a programmer/ software engineer and can do code reviews with Jan, so that helps. It also doesn't hurt that Jan is very smart, basically hand selected over multiple years by our CEO Vít who led a mathematics course for children/ teens and as such known Jan very well. Giving Jan a chance like this is basically a pilot combining normal education with practical, professional experience. Something like a very long internship on steroids :-)

I would still stress that static types are much less valuable than good variable/ function names and documentation/ clear code in my opinion and that maybe the complexity static types introduce isn't worth it overall. I also don't think, that static types as seen in e.g. Java or C# add any discernible degree of confidence - else somebody on the team would notice already. Jan didn't have problems navigating the code base even though most of the technologies, the language and the code base were completely new for him. Yes, anecdotal but I think it really is a valid and very important point.

I'm happy it's working for you well. The map changes were more in the line of changing core maps and then having to update every place they were used. IDEs are amenable to this as long as they can figure out the references. Cursive helped some but most of the work was still manual.

My point of reference between typed and untyped code is primarily with Typescript and Javascript since that's 99% of what separates the two. For what it's worth, I do have 21 years of experience and have been lead on my projects for a number of years. As the lead, I get enough benefit from the type annotations that I've told co-workers to just any type anything they can't get working immediately and I'll fix it in code review. It's enough of an overall team velocity increase and easier code reviews that it's a win.

I'm not trying to argue with your experience. Dynamic languages work fine for building products and Clojure is my favorite dynamic language by a significant margin. I'm sure I'll write more Clojure in the future. I'm just trying to explain the benefits since I had the same mindset 15 years ago and now prefer static types. I'll mention that don't particularly like C# or Java and their type systems are not expressive enough for me to prefer over dynamic language.

I agree that at large scale, types are one of the few things that keeps a project from completely falling apart (and I love lisp, but I would have a really hard time convincing my colleagues to adopt a dynamic language), but this seems counter to that:

> I've told co-workers to just any type anything they can't get working immediately and I'll fix it in code review

If you’re co-workers aren’t able to work with the types, how can they receive any benefits?

Not everyone is at a hyper growth place, but those that are would have zero luck with this pattern.

> If you’re co-workers aren’t able to work with the types, how can they receive any benefits?

There's plenty of distance between unable to work with types at all and knowing the full breadth of the TS type system. I've worked with plenty of people who weren't enthusiastic about types and this is my way of handling those objections. Even someone who doesn't know/care about types gets the IDE features from the types.

I have yet to have someone persist in sending me lots of any types past two weeks because having your work constantly corrected is embarrassing. I don't expect everybody to care about the type system past generics so if someone wants to write a basic index type instead of the more correct keyof or opts for any over figuring out a conditional intersection type, I'll take care of it in code review. I'd rather have them writing code than reading TS documentation to wrangle advanced types and people do look at the commits when they go in and learn the tricks over time.

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