Using Kotlin how can a declare and call a function that takes a list of functions as a parameter. I've used parameters in functions that are a single function, but how do I do this for a list of functions?
This question shows how to send a single function to a function: Kotlin: how to pass a function as parameter to another? What would be the best way to do this for a list of functions?
You can declare it using vararg. In this example, I declare a variable number of functions that take and return String.
fun takesMultipleFunctions(input: String, vararg fns: (String) -> String): String =
fns.fold(input){ carry, fn -> fn(carry) }
fun main(args: Array<String>) {
println(
takesMultipleFunctions(
"this is a test",
{ s -> s.toUpperCase() },
{ s -> s.replace(" ", "_") }
)
)
// Prints: THIS_IS_A_TEST
}
Or the same thing, as a List:
fun takesMultipleFunctions(input: String, fns: List<(String) -> String>): String =
fns.fold(input){ carry, fn -> fn(carry) }
fun main(args: Array<String>) {
println(
takesMultipleFunctions(
"this is a test",
listOf(
{ s -> s.toUpperCase() },
{ s -> s.replace(" ", "_") }
)
)
// Prints: THIS_IS_A_TEST
)
}
