CODEWITHSUNDEEP
scalafunctional-programming
Maths noob
Maths noob

Reputation: 1802

"bundling" functions in Scala

Let's say I have: 

val sayHello: Int => Unit = {_ => println("hello")}
val sayHi: Int => Unit = {_ => println("hi")}

And a function such as foo :

val foo: Int => Unit = {
  sayHi
}   
foo(123) //= prints hi

Is there a way of writing this:

val bar: Int => Unit = {
  i =>
    sayHello(i)
    sayHi(i)
}

without the i parameter? so that I can run both sayHi and sayHello?

I mistakenly had in my code the following:

val foo: Int => String = {
  sayHello
  sayHi
}

but this only uses the last expression and sayHello is not run.

In general, if this functions were to return anything other than Unit, let's say what is the idomatic way of bunlding these functions so that 

val Hello: Int => String = {_ => "hello"}
val Hi: Int => String = {_ => "hi"}

what is the most idomatic implementation of the function bar:

def bar: Int => Seq[String]

such that:

bar(123) // returns List("hello","hi")

Upvotes: 1

Views: 62

Answers (1)

Tzach Zohar
Tzach Zohar

Reputation: 37832

How about: 

def bar: Int => Seq[String] = i => Seq(Hello, Hi).map(_(i))

For the Unit-returning functions case, you can replace the map with foreach:

def bar: Int => Unit = i => Seq(Hello, Hi).foreach(_(i))

Upvotes: 1

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