sajjadyousefnia

fun <T : Number> oneHalf(value: T): Double {
return value.toDouble() / 2.0
}
>>> println(oneHalf(3))
1.5

sajjadyousefnia

interface List<T> {
operator fun get(index: Int): T
// ...
}

sajjadyousefnia

>>> val <T> x: T = TODO()
ERROR: type parameter of a property must be used in its receiver type

sajjadyousefnia

val authors = listOf("Dmitry", "Svetlana")
val readers = mutableListOf<String>(/* ... */)
fun <T> List<T>.filter(predicate: (T) -> Boolean): List<T>
>>> readers.filter { it !in authors }

sajjadyousefnia

val letters = ('a'..'z').toList()
println(letters.slice<Char>(0..2))
println(letters.slice(10..13))

sajjadyousefnia

Error:(12, 34) Kotlin: Illegal usage of inline-parameter 'predicate' in 'public inline fun inlinedFilter(list: List<Int>, predicate: (Int) -> Boolean): List<Int> defined in functiontypes in file Inline.kt'. Add 'noinline' modifier to the parameter declaration

sajjadyousefnia

inline fun inlinedFilter(list : List<Int>, predicate : (Int) -> Boolean) : List<Int>{
    val function = predicate
    return list.filter(predicate)
}

sajjadyousefnia

public static final boolean filterLessThanTwo(int input) {
    return input < 2;
}

public static final void lambdaInstanceTest() {
    List list$iv = CollectionsKt.listOf(new Integer[]{1, 2, 3});
    Iterable $receiver$iv$iv$iv = (Iterable)list$iv;
    Collection destination$iv$iv$iv$iv = (Collection)(new ArrayList());
    Iterator var4 = $receiver$iv$iv$iv.iterator();

sajjadyousefnia

public static final boolean filterLessThanTwo(int input) {
    return input < 2;
}

public static final void lambdaInstanceTest() {
    lambdaInstance((Function1) new Function1<Integer, Boolean>() {
        @Override
        public Boolean invoke(Integer integer) {
            return filterLessThanTwo(integer);
        }

sajjadyousefnia

inline fun inlinedFilter(list : List<Int>, predicate : (Int) -> Boolean) : List<Int>{
    return list.filter(predicate)
}

fun filterLessThanTwo(input: Int) = input < 2

fun lambdaInstance(predicate: (Int) -> Boolean) {
    val list = listOf(1,2,3)
    val newList = inlinedFilter(list, predicate)
    println(newList)