CODEWITHSUNDEEP
functiongenericsoverridingkotlin
ruX
ruX

Reputation: 7472

Overriding function with generics in kotlin

For example I have following sample code

fun f<T>( cb: (T, Int) -> Unit ): Unit {
  println("f called with cb which accepts 2 arguments"); 
}

fun f<T>( cb: (T) -> Unit ): Unit {
  println("f called with cb which accepts 1 argument"); 
  f<T> {item, position -> cb(item) }
}

fun main(args : Array<String>) {
  f { item -> }
  f { item, position -> }
}

Obliviously I want f function choose right implementation depends on amount of arguments I'm going to pass to closure

Currently kompiller gives me error:

(8, 7) : Overload resolution ambiguity: 
internal fun <T> f(cb: (T, kotlin.Int) -> kotlin.Unit): kotlin.Unit defined in root package
internal fun <T> f(cb: (T) -> kotlin.Unit): kotlin.Unit defined in root package

Code in online sandbox: http://kotlin-demo.jetbrains.com/?publicLink=100745728838428857114-628607155

Compiller version: org.jetbrains.kotlin:kotlin-gradle-plugin:0.10.770

UPD: related issue on youtrack: https://youtrack.jetbrains.com/issue/KT-6939

Upvotes: 3

Views: 2106

Answers (1)

ruX
ruX

Reputation: 7472

Thanks to @miensol I realized it was my mistake. I forgot to specify type for T while calling f().

Fixed code:

fun f<T>( cb: (T, Int) -> Unit ): Unit {
  println("f called with cb which accepts 2 arguments"); 
}

fun f<T>( cb: (T) -> Unit ): Unit {
  println("f called with cb which accepts 1 argument"); 
  f<T> {item, position -> cb(item) }
}

fun main(args : Array<String>) {
  f<String> { item -> }
  f<Boolean> { item, position -> }
}

Upvotes: 4

Related Questions