Question

I’m trying to write a simple wrapper class in F# that takes a function that returns a string, and returns a function that takes the same parameters and returns the string from the input ‘wrapped’.

The following code works for functions that take a single variable (so test works fine):

open System

let myFunc anotherFunc =
    fun x -> "boo" + anotherFunc x + "unboo"

let Func2 toDouble =
    (toDouble * 2).ToString ()

let test = myFunc Func2

let Func3 numOne numTwo =
    (numOne * numTwo).ToString ()

let test2 = myFunc Func3

do
    Console.WriteLine(test 10)
    Console.WriteLine(test2 5 10)

But because fun x -> specifies a single parameter, test2 is not valid code. Is there a piece of syntax that would allow for this construct?

Answer 1

Your function works.
The problem is in your last line when you do

let test2 = myFunc Func3

should be

let test2 x = myFunc (Func3 x)

UPDATE:

I’m assuming you don’t want to change Func3. Otherwise the solution from Tomas could be what you need.