"enums represent a different and incompatible concept in every language I know."

Enums has always felt very natural in every modern languages i've tried (swift and rust, for example), even with associated values. The underlying "sum type" concept also is very intuitive, and seems very complementary to structs for example.

Can you expand a bit on what you mean ?

Sum types are cool. Many languages implement enums which are not tagged union sum types (even when language has rich sum types)

https://en.cppreference.com/w/c/language/enum

https://learn.microsoft.com/en-us/dotnet/csharp/language-ref...

https://docs.python.org/3/library/enum.html

https://api.rubyonrails.org/v5.2.4.5/classes/ActiveRecord/En... https://sorbet.org/docs/tenum

https://docs.oracle.com/javase/tutorial/java/javaOO/enum.htm...

https://dart.dev/language/enums

https://www.postgresql.org/docs/current/datatype-enum.html

https://dev.mysql.com/doc/refman/8.4/en/enum.html

https://zig.guide/language-basics/enums

https://www.erlang.org/eeps/eep-0013

https://hackage.haskell.org/package/planet-mitchell-0.1.0/do...

https://www.ibm.com/docs/en/openxl-fortran-aix/17.1.1?topic=...

This. I find Swift and Rust enums, which are indeed very similar, to be incredibly good at modelling the real world. For example the standard geospatial vector types which are heterogeneous and even recursive in the case of GeometryCollections can be modelled and operated upon very cleanly.

Have you tried them in Java?

Java enums are more or less a “multiton” (as in singleton - for each value each)

And if you want rust style enums in Java you can use sealed types.

Rust has IMHO the best implementation of enums ... Mixed with match it is super powerful

Don't forget, Rust was first implemented in Ocaml, You can guess where those best enums come from.

Kotlins enum classes are quite similar, probably even inspired by rust or prior ML languages. And there's `when` as an alternative to match.

Kotlins syntax is in general a bit underrated imo and I disagree that Java is up to par.