I cannot access a function in a custom class; no matter what I try it comes up with errors

Question

import Cocoa

public class Ut {
    public func foo(m: Int) -> Int {
        return m*m
    }
}

class ViewController: NSViewController {

    let j = 3
    let k = Ut.foo(j) // 'ViewController.Type' does not have a member named 'j'

...

Answer 1

Unfortunately, you can’t access other properties when giving properties their initial values:

struct S {
    let a = 1
    // error: S.Type does not have a member named a
    let b = a + 1
}

Instead, you have to initialize these values inside init:

struct S {
    let a: Int
    let b: Int

    init() {
        // note, a must be initialized in here
        // too if b relies on it
        a = 1
        b = a + 1
    }
}

(also, it looks like you’re using Ut.foo as a class-level function but it’s a member function - but this particular error is about the property init)

Answer 2

You have to make your foo(m: Int) as class function in order to call directly like that. Otherwise, you have to create an instance of Ut then call foo() on to this instance

class func foo(m: Int) -> Int {
        return m*m
}

then in other place: let k = Ut.foo(j)

If you pass j as parameter, this call must be placed inside a function, not at class level. If you want to call at class level, pass a value (like: let k = Ut.foo(5) )