Couple of `value class` queries thread

Question

Jonathan Mew · Answer

We currently have some Microtype classes which wrap a single value So for example we have a StringMicrotype abstract class extended by a bunch of others I was exploring the possibility of migrating to inline value classes instead

Jonathan Mew · Answer

I ve hit 2 issues so far We have some string types we effectively would like to be case insensitive I think I d need to do something like call a companion `MyCaseInsensitiveString new s ` and pass the lowercased string to a private constructor to preserve that logic We have Exposed Column Types related to our Microtypes so we have an `abstract class StringMicrotypeColumnType lt T StringMicrotype gt ` extended by a few others each associated with the relevant Microtype e g `EmailColumnType` associated with `Email` Is there a way to use generics to refer to any value class that contains a String value

Jonathan Mew · Answer

Perhaps these types are legitimately better as non value classes I m not bothered about improving performance just thought it might mean less more concise code

Jonathan Mew · Answer

``` JvmInline value class EmailAddress private constructor val value String companion object fun new value String EmailAddress = EmailAddress value lowercase ```

Jonathan Mew · Answer

the microtypes are pretty concise already this would mainly just cut out some class hierarchy

Stephan Schroeder · Answer

I like your value class with factory method +1 I m fairly certain that there s no way to use generics to accept any value class containing a String since this is basically the opposite of what you d normally want JvmInline value classes for more type safety But you could maybe implement an Interface on your value classes and use that ```interface StringContainer fun getContent String ```

Jonathan Mew · Answer

looks like I might get away with ```interface StringContainer val value String JvmInline value class EmailAddress private constructor override val value String StringContainer ``` Not sure it s worth it though thinking face Thanks for the input