راهنمای ایجاد DSL در کاتلین – به زبان ساده

1class Car {
2   fun drive(miles: Int) {
3      ...
4   }
5}
6val car = Car()
7car.drive(10) // normal stuff

1class Car {
2   infix fun drive(miles: Int) {
3      ...
4   }
5}
6val car = Car()
7car drive 10 // no brackets! no dots!

1val name = "Ahmed Riz"
2name.shout() // won't compile as shout() is not part of String class

1fun String.shout() {
2   println("$this !") // this refers to the value of string itself
3}
4val name = "Ahmed Riz"
5name.shout()  // works! and prints out: Ahmed Riz !

1// a higher order function
2fun process(value: Int, operation: (Int) -> Unit) {
3    operation(value)
4}
5// when calling, we can pass in a lambda expression
6process(10, { value -> println(value) })
7// and because it's the last param, we can extract it out
8// just to clean things up even further 
9process(10) { value -> println(value) }

1// slight change to the previous higher order function
2// now instead of operation: (Int) -> Unit
3// we'll do operation: Int.() -> Unit
4// This makes Int the receiver type
5fun process(value: Int, operation: Int.() -> Unit) {
6    value.operation()
7}
8// usage now becomes
9process(10) { println(this) } // prints out: 10

1val myProfile = "Ahmed Rizwan" profile {
2    age = 90
3    phone = "123 456 789"      
4}

1class Profile(
2    val name: String,
3    var age: Int? = null,
4    var phone: String? = null
5)
6
7infix fun String.profile(create: Profile.() -> Unit): Profile {
8    val profile = Profile(this)
9    profile.create()
10    return profile
11}