[yogthos]

The whole premise of static typing is that type errors can be caught at compile time. Java type system allows for kinds of errors to be caught at compile time that will not be caught by using protocols in Clojure. Yes, you can run the compiler at run time, but that's entirely besides the point here.

These libraries aren't using protocols for type safety though, they're using them as a performance optimization. That's certainly a perfectly fine reason to use protocols, and I agree that it's a completely legitimate use case. It's the whole right tool for the job thing. If you're writing something where performance is the top concern, then that's what protocols are for.

I very much agree with you that that there are people who focus on low level code, and those who focus on application level code. The style of coding will be different depending on the type of problem you're solving. You're right that I failed to qualify my original statement regarding protocols being an anti-pattern.

You're absolutely correct that we should take a pragmatic approach towards using language features. Hence why the context of whether protocols are the right tool to each for lies in the type of code you're writing. And of course, some people find it easier to have more structure to help with their reasoning. Although, I'd argue tools like Malli work better there.

To sum up, I'm not arguing against protocols being useful or that there's no place for them. We started this discussion talking about whether protocols provide equivalent guarantees to Java's type system. I disagree regarding that. However, I also don't think that this is a real problem. Otherwise, use of something like core.typed would've become prevalent by now.

[huahaiy]

I wrote my library this way for both performance AND type checking reasons. You cannot tell me the reasons why I wrote my code my way. That is just absurd.

In any case, it is possible to write Clojure in a way that is type checked at compile time. And it is an acceptable way to write Clojure. I just want to clear the air.

[yogthos]

I'm not telling you the reasons why you write code the way you do. I'm just telling you about my experience of using the language, which clearly differs from yours. I never found protocols to be useful as a type checking tool, and I find they're not necessary for optimizations most of the time. I spent a lot of time profiling and optimizing Selmer, this is the only protocol that turned out to be necessary for performance https://github.com/yogthos/Selmer/blob/master/src/selmer/nod...

If you find protocols are a helpful tool to structure code that's great, keep using them. Nobody is telling you not to. However, try to accept that different people use the language in different ways. Try to follow your own advice and not to be dogmatic about it.