CODEWITHSUNDEEP
scalafunctional-programmingfunctional-dependencies
mavarazy
mavarazy

Reputation: 7735

How to define functional argument with implicit parameters

I have a simple function, that I use to generate generic Spec2 tests:

def check[T <: ED](actual: Seq[T], expectedFile: File)(implicit format: Format[T], ordering: Ordering[T]): Seq[MatchResult[Any]] 


def generateCheck(clientName: String, patientId: String, folder: File)

Where generateCheck calls check allot. I want instead of defining check as a separate function, use it as functional argument for generateChecks

I want to have something like this:

def generateCheck(clientName: String, patientId: String, folder: File, check: ???)

For now I made a workaround, and just override check as needed, but I still wonder How can I define check as a functional argument?

Upvotes: 2

Views: 105

Answers (1)

Archeg
Archeg

Reputation: 8462

Ok. I actually thought this is simple, but it is not. I am missing a bit of insights into your code, but next may give you some ideas:

I don't think you can do implicits with anonymous functions. At least I haven't seen that anywhere done. But you can easily wrap it:

 class Check[T]()(implicit format: Format[T]) extends ((Seq[T], File) => Unit) {
    override def apply(v1: Seq[T], v2: File): Unit = ??? // your implementation
  }

So:

    def test(check: Check[Int]): Unit = {
      check(Seq.empty, new File("."))
    }

    test(new Check[Int]())

Or if you can refactor the function that doesn't need implicit context (I just think having implicit class is nice here, but not sure it is applicable to your case):

 implicit class Check[T](val f: (Seq[T], File) => Unit)(implicit format: Format[T]) extends ((Seq[T], File) => Unit) {
    override def apply(v1: Seq[T], v2: File): Unit = f(v1, v2) //do some processing and call f
  }

Now:

  def test(check: Check[Int]): Unit = {
    check(Seq.empty, new File("."))
  }

  test((a: Seq[Int], b: File) => {
    println("Hello world")
  })

But you need to remember to put types into your function, or manually wrap it in new Check[T]

Upvotes: 1

Related Questions