Not sure if this is the right channel, but: is there something new on that topic <https://discuss.ko...

# getting-started

[Manuel Dossinger]

Not sure if this is the right channel, but: is there something new on that topic https://discuss.kotlinlang.org/t/what-is-an-idiomatic-way-to-create-a-read-only-wrapper-for-a-class/10929 ? I.e., I'd like to have a class data class MutableClass(var my1, var my2, var my3...) and a fitting data class ImmutableClass(val my1, val my2, val my3...). So the only difference is, that all members of one class are var and the members of the other one are val and of course I don't want to write the list of members twice 🙂

[Joffrey]

I don't believe there is any automatic way to do this at the moment. Also, I'd like to point out that immutable != read-only, so even automatically converting var to val in some way via a language feature wouldn't guarantee immutability (it would depend on the implementation of the class itself)

[edrd]

You could write a symbol processor to scan your data classes and generate a mutable/immutable version of it, also with functions to convert between one another.

[Manuel Dossinger]

@Joffrey thanks, this is a good point; I guess I was thinkin in Rust 🙂
@edrd I'd rather not introduce "non-standard" code, but thanks

[Paul Griffith]

https://github.com/Kotlin/KEEP/blob/master/notes/value-classes.md#updating-immutable-classes
this KEEP might be interesting reading

[Joffrey]

Yeah the value class feature is pretty interesting, but I think this is not what the OP is after here, the goal was to write only once the immutable and mutable version of the class, and somehow have both generated from it