Allow initialization and addition of AcknowList

[ChaosCoder]

I am using Acknowlist with SwiftUI and generate the list from the package, which works great.

However, I need to add items to the list, that are not in the package (e.g. graphics licenses, etc.). But the defined + operator for two AcknowList is not public. Initializing of a AcknowList is also not possible from outside the package and the properties including the acknowledgements on an AcknowList are defined with let and therefor can not be mutated.

This PR fixes the first two things, so you can do stuff like:

let listFromPackage = try! AcknowPackageDecoder().decode(from: packageData)

let customList = AcknowList(headerText: nil, acknowledgements: [
    Acknow(title: "Some Graphics", license: "License of the graphics")
], footerText: nil)

let combinedAcknowList = customList + listFromPackage

but not (because the acknowledgments property is a let instead of a var):

let url = Bundle.main.url(forResource: "Package", withExtension: "resolved")!
let data = try! Data(contentsOf: url)
var list = try! AcknowPackageDecoder().decode(from: data)
list.acknowledgments.append(Acknow(title: "Some Graphics", license: "License of the graphics"))

[vtourraine]

Hello Andreas, and thanks a lot for preparing this pull request!

I agree this would be a useful change. There’s just one aspect I would like to preserve as-is: the properties being constants (let) instead of variables. I think you can still achieve the same outcome, using the public initializer or the + operator. Could you please roll this back before I merge, or let me know if I’m missing something?

[ChaosCoder]

Done.

I think the API of your library would improve by using var for the properties (as AcknowList is a struct), you can read about pros and cons here: https://swiftbysundell.com/articles/let-vs-var-for-swift-struct-properties/#is-immutability-always-the-answer or https://forums.swift.org/t/to-var-or-let-struct-properties/52363, but I am not gonna argue here as it is your choice.

[vtourraine]

I sincerely appreciate your feedback on this. I’ll stick to the current approach for now, but I’ll keep an open mind in case it needs revising. Thank you!

[vtourraine]

Release as version 3.4.2