class Person(firstName: String) {
}

class Customer(name: String) {
    init {
        logger.info("Customer initialized with value ${name}")
    }
}

class MyView : View {
    constructor(ctx: Context) : super(ctx)

    constructor(ctx: Context, attrs: AttributeSet) : super(ctx, attrs)
}

open class Base {
    open fun v() {}
    fun nv() {}
}

class Derived() : Base() {
    override fun v() {}
}

class Address {
    var name: String = ...
    var street: String = ...
    var city: String = ...
    var state: String? = ...
    var zip: String = ...
}

fun copyAddress(address: Address): Address {
    val result = Address() // there's no 'new' keyword in Kotlin
    result.name = address.name // accessors are called
    result.street = address.street
    // ...
    return result
}

val simple: Int? // has type Int, default getter, must be initialized in constructor
val inferredType = 1 // has type Int and a default getter

var b: String? = "abc"
b = null // ok

val l = b.length // error: variable 'b' can be null

val l = if (b != null) b.length else -1

b?.length

val l = b?.length ?: -1

fun MutableList<Int>.swap(index1: Int, index2: Int) {
    val tmp = this[index1] // 'this' corresponds to the list
    this[index1] = this[index2]
    this[index2] = tmp
}

fun reformat(str: String, 
    normalizeCase: Boolean = false, 
    upperCaseFirstLetter: Boolean = false,
    divideByCamelHumps: Boolean = true,
    wordSeparator: Char = '/') : String {..}

reformat(str,
    normalizeCase = true,
    upperCaseFirstLetter = true,
    divideByCamelHumps = false,
    wordSeparator = '_'
)

reformat(str, wordSeparator = '_')

fun double(x: Int) = x * 2

// Using R.layout.activity_main from the main source set
import kotlinx.android.synthetic.main.activity_main.view.*

class MyActivity : Activity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        view.textView.setText("Hello, world!")
        // Instead of findView(R.id.textView) as TextView
    }
}

data class User(val name: String, val age: Int){
    fun foo(): String {
        ....
    }
}

class Delegate {
    operator fun getValue(thisRef: Any?, property: KProperty<*>): String {
        return "$thisRef, thank you for delegating '${property.name}' to me!"
    }
 
    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {
        println("$value has been assigned to '${property.name} in $thisRef.'")
    }
}

println(e.p)
//Example@33a17727, thank you for delegating ‘p’ to me!


e.p = "NEW"
//NEW has been assigned to ‘p’ in Example@33a17727.

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