for (firstIndex in (0..inputs.size - 2)) {
        for (secondIndex in (firstIndex + 1..inputs.size - 1)) {
            val firstInput = inputs[firstIndex]
            val secondInput = inputs[secondIndex]
            ...
        }
    }

.asSequence()

anything that extends x

data class CustomMenuItem (val name: String, val action: (E ? extends ViewModel) -> Unit)

With Java, in-memory data “storage” comes in four shapes: variables, parameters, fields, and constants, in order of scope.

With Kotlin, parameters are similar with a few variations. They are final (so they cannot be assigned a new value), can have a default value (so we can omit > them when calling it) and their names matter (as we can use them when invoking).

Now, for the other three, things are more different. As in, they are all defined as properties.

enum Optional<T> {
    case None
    case Some(T)
}

companion object { 
        private val log = LoggerFactory.getLogger(MyClass::class) // TODO

java.etc

context

presenter

http request

data

shared preference

list.map {
  if (condition) {
    42
  }
  0 
}