I m not sure when exactly I d use a value class Does it make kotlinlang #getting-started

class SelectionMenuOptionBuilder(val options: MutableList<SelectOption> = mutableListOf()) {

    fun option(label: String = "", value: String = "", description: String? = null, emoji: Emoji? = null, default: Boolean = false) { options += SelectOption(label, value, description, emoji, default)}
    fun add(selectOption: SelectOption) { options += selectOption }
    fun addAll(selectOptions: Iterable<SelectOption>) { options += selectOptions }
    fun addAll(selectOptions: Array<SelectOption>) { options += selectOptions }

}

Klitos Kyriacou

02/06/2022, 6:32 PM

This doesn't look like a builder. Conventionally a builder would create its own mutable list and have a

build()

function that returns an immutable

List

Nick Allen

02/06/2022, 6:43 PM

That’s Java builders, Kotlin builders are generally a single function that take a lambda where you can populate a mutable value or do other work and then they return an immutable value or other result. You could just use

buildList

Mike Sutjipto

02/06/2022, 7:39 PM

are you wondering if your builder class should be a value class? doesn't really feel like the typical usage of a value class - normally i would use it to wrap something like a string (or other primitive type) where I wanted the semantics of that value to be more clear and also involved in the type system. so e.g. something like

value class UserId(val value: String)

is a common way of using them (at least for me)

👍 1

👍🏻 1

Mykola Gurov

02/06/2022, 7:48 PM

SelectOption

could’ve been a good candidate for the data class. The builder we see here is just a convenience wrapper around the mutable list, and TBH I’m not sure I even see any added value here since the clients of this class could’ve just used the same

mutableList

directly

Jan

02/06/2022, 10:28 PM

Okay thanks

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