KFunction
- Kotlin course
- Advanced
- Lesson 63/83
- 5 min
Learn method info with KFunction.
Function info with KFunction
KFunction holds a reference to a function. It is obtained with ::functionName. name gives the function name; parameters gives the parameter list.
Example: fun greet(name: String): String = "Hello, $name!". val fn = ::greet. fn.name returns "greet". fn.parameters.size gives 1. This pattern inspects function metadata.
parameters and returnType
KFunction.parameters returns a list of parameters; each has a name and type. returnType gives the function's return type.
Example: fun add(a: Int, b: Int): Int = a + b. ::add.parameters.size returns 2. ::add.returnType gives the Int type. This info is used to process function signatures dynamically.
Practice Print the greet function name
Define fun greet(name: String): String that returns "Hello, $name!". In main take the reference val fn = ::greet and call println(fn.name).
Starter code
// greet function: returns Hello, {name}!
// in main take fn reference, print its nameSample solution
fun greet(name: String): String {
return "Hello, $name!"
}
fun main() {
val fn = ::greet
println(fn.name)
}Expected output
greet
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Match the KFunction parts
| Term | Meaning |
|---|---|
::greet |
Function reference |
fn.name |
Function name |
fn.parameters |
Parameters |
fn.returnType |
Return type |
2 What does KFunction's name property return?
- Parameter count
- Function name Correct answer
- Return type
- Call result
Explanation: name gives the function name.
3 Complete the KFunction reference
fun greet(name: String): String = "Hello, $name!"
val fn = ____fun greet(name: String): String = "Hello, $name!"
val fn = ::greetExplanation: ::greet gives a KFunction reference.