inline fun letterInRange(char: Char): Boolean = char.compareTo('a')  || char.compareTo('b') ||
                                                   char.compareTo('c') || char.compareTo('d') ||
                                                   char.compareTo('e') || char.compareTo('f') ||
                                                   char.compareTo('g') || char.compareTo('h')

return foo?.let { doStuff(it, bar, baz) } ?: false

saleCars.sortedWith(compareBy(nullsLast<Double>()) { it.hot_deal_likelihood })

validator: ValidationContext.(String?) -> ValidationMessage?

ValidationContext

ValidationMessage

.(String?)

return when {
    filename.isNullOrBlank() -> context.error("Cannot be blank")
    !File(filename).exists() -> context.error("File does not exist")
    !File(filename).isFile -> context.error("Not a file")
    !File(filename).canRead() -> context.error("Permission Denied")
    else -> when (val code = canConnect(filename)) {
        SQLiteErrorCode.SQLITE_OK -> context.success()
        else -> context.error(code.message)
    }
}

when

else

when

kotlin
   private val queue: Deque<() -> Unit> = LinkedList()

    fun addJob(req: String, callback: (String) -> Unit) {
        this.queue.offer {
            callback(req)
        }
    }

    //WILL RUN LATER AT AN UNSPECIFIED POINT OF TIME
    fun pullJob() {
        val func = this.queue.poll()
        if (func != null)
            func()
    }

for (it in this.list) {
                if (it == example) {
                    //do smth
                    break
                }
            }

this.list.foreach{
    if(it==example) //do smth
}

data class Foo(
   val bar : Baz
)
data class Baz(
   val smth : String
   val zzz : String?
)

zzz

zzz

data class Attachment(val filename: String?, val mimeType: String?)

val Attachment.isImage: Boolean
    get() = this.mimeType?.contains("image") == true

fun Attachment.load(): Image { ... }

require

check

Regex("""^[\d]{9}$""")

Regex("""^[\d]{9}${'$'}""")

val foo : SomeInterface = inputVariable
val bar = if (foo is implA) (foo as implA) else (foo as implB)

bar

bar.fieldOnlyOnImplementations