scastie VS mdoc

From personal experience Scala also works. It's 100% possible to learn monads using https://scastie.scala-lang.org/ as a scratch pad.

Instead I typically use https://scastie.scala-lang.org, or an ammonite script, or just create a new file that extends App in my test directory. The thing that worksheets do better is that you can import things from your project (like the little app in the test dir) but they also show runtime values (like repl or scastie). However I've just never gotten them to actually work.

I strongly recommend you play around with the local Scala REPL. I have Scala 2.13 on my main dev computer and Scala 3 on my other computer. The local REPL will let you know when things are deprecated and give you hints as to what you should use instead. Scastie https://scastie.scala-lang.org/ can also be a big help.

Operationally, as you might expect from a language borne from academia, Scala tooling can be problematic and compilation can be slow--particularly if you are not yet using Scala 3, which only recently emerged and is very slowly percolating through the ecosystem (Remember the Python 2 to Python 3 transition?). But type inference, a vast standard library, and the time-tested reliability of the JVM make you very productive once you get the hang of them. Performance varies with the JVM you're running, but regardless you do have to contend with the size of compiled objects and the latency of garbage collection at runtime. When you want to experiment, you can skip the ceremony of writing a class or test and instead use a command-line REPL, an online REPL called Scastie you can share, or an outstanding third-party command-line REPL called Ammonite. Dependency management is achieved with SBT typically but also more general JVM build tools like Gradle and Maven.

I am using https://scastie.scala-lang.org/ which does compile server side in Scala. The UI is a bit hard to handle tho.

https://github.com/scalacenter/scastie#how-do-i-embed-scastie

Literally what scaladoc is, it comes with sbt. Although, it's better when enhanced with mdoc so that you get the standard microsite template like these. It would be nice to have an sbt serveDocs and if everyone would host their docs for external linking, but javadoc doesn't do that either.

The good news is that scaladoc is produced by default by sbt and published by default. So you can often pull it from the same repository your library jar came from, extract it with zip, and read the docs. But that's also totally unnecessary - javadoc.io allows you to put in your module info and serves the docs for you, so if there's an older version you can access the documentation this way. Rely on the type signatures, since they can't lie, whilst comments (including scaladoc comments) can. Honestly, library authors should be using mdoc and including examples on every public method, and that type of documentation is something you can almost always contribute to a project for a quick pr kudos.

I know it's not new but the "Snippet validation and results (mdoc)" features in mdoc are so cool. Really takes some of the tedium out of working with documentation since you can know that as you evolve your code the compiler will make sure you keep the docs in sync. Whole new level of Readme-Driven Development