iron VS Http4s

Scala has quite good support for refined types across multiple libraries. A solution using the refined library might look something like

> The output you see is not generated by python.

Obviously, as running the code generates a very different output…

> It's generated by an external type checker.

I know.

But again, you didn't say that.

You said the above code "generates" this…

Maybe you've heard that by now somewhere: Words matter… ;-)

> The context is python. We're talking about python. I'm making a statement about python.

No, you made a statement about type checking. Here the full quote once again:

> The contents of a string can't be type checked and if all methods are defined this way on a class none of it can be checked.

Nothing in this statement is about Python.

All I did was just proving your words once again to be nonsense: You can statically dispatch (which involves static type checking!) just fine on strings. My (Scala) code is prove of this fact.

> There is literally nothing in my statement to indicate I'm making a general statement about type checking.

LOL. Do you actually know what you're writing? Once more:

> The contents of a string can't be type checked and if all methods are defined this way on a class none of it can be checked.

That's a general statement… It couldn't be even more general, actually.

> But I will say checking for the contents of a string is rare for a type checker to do. That is a general statement that is generally true.

Once again complete nonsense.

There are whole libraries doing more or less nothing else than handling singleton types.

Whole software layers utilize that! But I guess you never heard of static data validation…

https://github.com/Iltotore/iron

You have so little clue, but such a big mouth… That's so embarrassing.

A helpful tip: Stop spiting out maximally general claims (because these are almost always wrong!), and think about what you're actually writing.

What's in your fantasy, or what you "may have meant" is irrelevant!

> The guy made factually incorrect statements and so did you.

That's exactly what I'm talking about: You're a severe DK victim as it seems…

> It's just true that he's wrong.

No, actually you are wrong with almost every claim, like I've proven now several times. And this nonsense still didn't stop… Oh, boy!

> people shouldn't get worked up about someone else identifying a mistake.

Think about that once again. Especially in the context that it's you who is wrong here with almost everything you say.

And no, nobody is "pedantic". It only gets quite unrealistic that someone who doesn't even get banal prose straight would be able to write any code. Because the computer is actually very pedantic. And after production is on fire you can't just come to your boss and excuse yourself with "but I've meant this differently, just the stupid computer did again not understand what I've meant".

But to be honest this would actually explain:

> I've likely worked for more companies then you in the last 5 years or so due to my personality. I don't stay at one place for long.

I have some suspicions to why you don't stay anywhere for long… And yes, that would be indeed related to personality…

You might want to check out Iron.

And there is a beginner-friendly ticket: Add alias for True constraint and IronType[A, True]

Annotation is not the only way (and probably not the best IMHO) to do refined types. You might be interested in Iron in Scala 3 or Refined in Scala 2/3.

The second major version of Iron is out, featuring a complete rewrite on top of better foundations.

http4s is a Typelevel project, and therefore falls into the "program in Scala as if it were Haskell" category. Many people find this off-putting, but honestly, I think with the resources listed above, this is the option at the best intersection of "mature" and "well-documented" available in Scala. The reason it's off-putting to many people is that Haskell-style pure FP isn't mainstream, so it isn't so much a matter of learning a new technology as it is a matter of learning a new paradigm, which necessarily means surfacing and unlearning things you already know, and perhaps confronting the uncomfortable feeling that things you thought were "fundamental," "have to be that way," aren't, and don't. I personally found this process liberating. But not everyone does.

If you want a mature REST API library, I recommend http4s. Be aware, though, that it’s based on purely-functional programming with Cats, cats-effect, and fs2, so if you’re not familiar with them or aren’t prepared to commit to the paradigm, the learning curve may be daunting, seem pointless, or both.

See also cats-effect and fs2. cats-effect gives you your IO Monad (and IOApp to run it with on supported platforms). fs2 is the ecosystem’s streaming library, which is much more pervasive in functional Scala than in Haskell. For example, http4s and Doobie are both based on fs2.

Most important/known: * https://http4s.org/ - an HTTP client/server * https://github.com/typelevel/fs2 - streaming * https://github.com/tpolecat/doobie - JDBC

Scala devs are too busy wondering about free monads and F[Request[F] => Response[F]]. I am very pleased by http4s, Doobie, ScalaJS, and the whole ecosystem, really: https://http4s.org

In reality, your performance issues will not be http4s, but something else. That being said, there are improvements that http4s can and is making, and I'm quite excited about the future 1.0 release, which has some important and fundamental performance improvements already, like a a 125% performance improvement on the plaintext benchmark from https://github.com/http4s/http4s/pull/6091 - and finally, yes, akka-http does have very good performance, but you can also get good performance out of http4s.

http4s for REST services.

This is a long list of misunderstandings I don’t have the patience to unpack. Instead, let me refer you to the links in my top comment in the thread, then suggest you learn at least http4s, a purely-functional web service library that’s been used in production for a decade or so now.

The most popular nowadays are - I guess - akka-http and http4s. You can also use Play if you don't want to start from scratch but prefer a framework-based approach.

There are functional frameworks: https://http4s.org/