How can I pass the parameter in the function num()? - scala

Question

object MatchTest4 extends App{
def matchTest(x: Any): Any = x match {
case 1 => def num(p: Int, q: Int): Unit = {
val sum = p + q
println(sum)
}
case 2 => def num(p: Int, q: Int): Unit = {
val sub = p - q
println(sub)
}
case 3 => def num(p: Int, q: Int): Unit = {
val mul = p * q
println(mul)
}
case 4 => def num(p: Int, q: Int): Unit = {
val div = p / q
println(div)
}
case _ => println("Invalid Choice")
}
println("Enter Your Choice")
val b= readInt()
println(matchTest(b))
}
Now I want to give parameter to the function num().Is it possible?

Answer 1

The below code should accomplish what you are trying to do. The changes I made were:
Removed the return type for the matchTest. Scala will automatically infer the return type as a function value.
Replaced the method definitions "num" by anonymous functions.
Modified the signature of your wildcard pattern match to also return a function consistent with other pattern matches. (This is a hack, I hope someone knows a better way)
You can run your returned anonymous functions like matchTest(4)(2,3) etc.
def matchTest(x: Any) = x match {
case 1 => (p: Int, q: Int) => {
val sum = p + q
println(sum)
}
case 2 => (p: Int, q: Int) => {
val sub = p - q
println(sub)
}
case 3 => (p: Int, q: Int) => {
val mul = p * q
println(mul)
}
case 4 => (p: Int, q: Int) => {
val div = p / q
println(div)
}
case _ => println("Invalid Choice"); (a: Int, b: Int) => println("Invalid Choice")
}