Features

As described in concepts, to use Knee you must annotate your Kotlin/Native declarations and they'll be made available in Kotlin/JVM. As a general rule:

• Use @Knee on callables functions or properties
• Use @KneeClass, @KneeInterface, @KneeEnum on types (or typealiases)

This way, the following Kotlin/Native code:

kotlin
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@KneeClass class User(val id: String)

@KneeClass class LoggedOutException : RuntimeException()

@KneeClass class Post @Knee constructor(@Knee val title: String, @Knee val author: User)

@KneeInterface typealias PostSavedCallback = (Post) -> Unit

@KneeClass class Database() {

    private val scope: CoroutineScope = ...
    private val disk: Disk = ...

    @Knee suspend fun getCurrentUser(): User {
       val user = disk.readCurrentUserSuspending()
       return user ?: throw LoggedOutException()
    }

    @Knee fun savePostAsync(post: Post, callback: PostSavedCallback) {
        scope.launch {
            disk.writePostSuspending(post)
            callback(post)
        }
    }
}

@Knee val AppDatabase: Database = ...

...can be seamlessly called from the JVM side - no boilerplate, no glue code, everything is handled for you:

kotlin
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suspend fun createPost(title: String): Post {
    val user = try {
        AppDatabase.getCurrentUser()
    } catch (e: LoggedOutException) {
        TODO("Handle this")
    }
    return Post(title, author = user)
}

fun savePost(post: Post) {
    AppDatabase.savePostAsync(post) { savedPost ->
        check(savedPost == post)
    }
}

We list most features supported by the Knee compiler below:

• Callables (functions and properties)
• Suspend functions and structured concurrency
• Exceptions
• Built-in types (primitives, nullables, collections)
• Enum types
• Class types
• Interface types, lambdas and generics
• java.nio Buffers types