Adds typed mutable copying to NSMutableCopying conformers

TypedMutableCopying.swift

import Foundation

protocol TypedMutableCopying {
    associatedtype ConstantVersion
    associatedtype MutableVersion

    var typedCopy: ConstantVersion { get }
    var typedMutableCopy: MutableVersion { get }
}

extension TypedMutableCopying where Self: NSCopying, ConstantVersion: NSCopying {
    var typedCopy: ConstantVersion {
        copy() as! ConstantVersion
    }
}

extension TypedMutableCopying where Self: NSMutableCopying, MutableVersion: NSMutableCopying {
    var typedMutableCopy: MutableVersion {
        mutableCopy() as! MutableVersion
    }
}

protocol TypedMutableCopying {
    associatedtype ConstantVersion = Self
    associatedtype MutableVersion

    var typedCopy: ConstantVersion { get }
    var typedMutableCopy: MutableVersion { get }
}

extension TypedMutableCopying where Self: NSCopying, ConstantVersion: NSCopying {
    var typedCopy: ConstantVersion {
        copy() as! ConstantVersion
    }
}

extension TypedMutableCopying where Self: NSMutableCopying, MutableVersion: NSMutableCopying {
    var typedMutableCopy: MutableVersion {
        mutableCopy() as! MutableVersion
    }
}

extension NSArray: TypedMutableCopying {
    typealias MutableVersion = NSMutableArray
}

extension NSAttributedString: TypedMutableCopying {
    typealias MutableVersion = NSMutableAttributedString
}

extension NSSet: TypedMutableCopying {
    typealias MutableVersion = NSMutableSet
}

extension NSData: TypedMutableCopying {
    typealias MutableVersion = NSMutableData
}

extension NSString: TypedMutableCopying {
    typealias MutableVersion = NSMutableString
}

extension NSDictionary: TypedMutableCopying {
    typealias MutableVersion = NSMutableDictionary
}

extension NSIndexSet: TypedMutableCopying {
    typealias MutableVersion = NSMutableIndexSet
}

extension NSOrderedSet: TypedMutableCopying {
    typealias MutableVersion = NSMutableOrderedSet
}

extension NSURLRequest: TypedMutableCopying {
    typealias MutableVersion = NSMutableURLRequest
}

extension NSCharacterSet: TypedMutableCopying {
    typealias MutableVersion = NSMutableCharacterSet
}

extension NSParagraphStyle: TypedMutableCopying {
    typealias MutableVersion = NSMutableParagraphStyle
}

#if canImport(UserNotifications)
import UserNotifications

extension UNNotificationContent: TypedMutableCopying {
    typealias MutableVersion = UNMutableNotificationContent
}
#endif

Usage:

let constant = NSParagraphStyle()
let mutable = constant.typedMutableCopy
let newConstant = mutable.typedCopy

#if canImport(UIKit)

should this be UserNotifications?

Yep. Thanks. I'm sure I've made that mistake before and I'll make it again 😆