I have this function:

fun uppercase(s: String) = s.uppercase()

And another function that can takes as a parameter a function as the one above:

fun print(uppercase: (s: String) -> String) {
    print(uppercase("Ana"))
}

And in main I call:

print {
    uppercase("Ana")
}

Why should I pass to the uppercase function the name twice? If I remove the argument in print function ("Ana"), I get an error. How to pass the String argument only once?

If I use:

print(uppercase) //I get StackOverflowError.

My goal is to pass a function that takes an argument of type String and returns the uppercase version and the print function and print the result. How can I solve this?

CodePudding user response：

you should write it as

print(::uppercase)

CodePudding user response：

  // regular function definition
fun printMe(s:String): Unit{
    println(s)
}
   // higher-order function definition
fun higherfunc( str : String, myfunc: (String) -> Unit){
   // invoke regular function using local name
    myfunc(str)
}
fun main(args: Array<String>) {
    // invoke higher-order function
    higherfunc("Like this",::printMe)
}