hey! I'm trying to write a generic function to set...

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[pepe]

hey! I'm trying to write a generic function to set a default value on a nullable property of an immutable object and I have two obstacles:
- can I constraint a type so it is a data class (implements a copy constructor)?
- can I address the right property in the copy constructor using the KProperty?

This is what I have so far:

fun <T: ???, R> T.setDefault(prop: KProperty1<T, R>, defaultValue: R): T =
        prop.get(this)?.let { this } ?: copy(??? = defaultValue)

P.S. maybe this I'm trying to do is stupid/not worth it, feel free to point it out

[Mike]

I assume the default can't be defined on the data class definition itself?

[pepe]

I understand, thanks, so there's no way to make this generic, right?