Kotlin

Parameter hints

data class User(val id: Int)

fun printSum(a: Int, b: Int) = println(a + b)

fun hintsDemo() {
    val u = User(0)     // calling constructor
    printSum(1, 1)      // calling function
}

Types

Property types	Controls whether hints should appear when assigning a value to a property whose type is not explicitly specified. `class User(_id: Int = 0) { val id = _id // inferred property type }`
Local variable types	Controls whether hints should show the type when a local variable, whose type is not specified, is assigned some value. The type is not shown for constants. `fun returnHello(): String = "Hello" fun hintsDemo() { val s = returnHello() // "s" gets the String type }`
Function return types	Controls whether hints should appear for functions with inferred return types. `fun sum(i1: Int, i2: Int) = i1 + i2 // the return type (Int) is inferred`
Function parameter types	Controls whether hints should appear for lambda parameters without a type. `fun hintsDemo() { listOf(1, 2, 3).filter { elem -> // parameter with inferred type elem >= 3 } }`

Lambdas

Return expressions

Controls whether hints should appear for multiline lambdas that return a value. This is useful in complex constructs, where it is easy to forget that a lambda is returning something.

fun numbers(): String {
    val numbers = StringBuilder()
    return with(numbers) {
        // "with" structure starts here
        for (letter in '0'..'9') {
            append(letter)
        }
        toString() // used as the return value
    }
}

Implicit receivers and parameters

Controls whether hints should appear for lambdas' implicit receivers.

fun numbers(): String {
    val numbers = StringBuilder()
    return with(numbers) {
        // the implicit receiver is "numbers" (StringBuilder)
        for (letter in '0'..'9') {
            append(letter)
        }
        toString()
    }
}

Kotlin﻿

Parameter hints﻿

Types﻿

Lambdas﻿

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Parameter hints

Types

Lambdas

URL path inlay