KVC without NSObject (NSPredicate)

Question

I'm trying to use NSPredicate like so:

let namePredicate = NSPredicate(format: "(username BEGINSWITH[c] $word)")

    if prefix == "@" {
        if countElements(word) > 0 {
            suggestionDatasource.users = (suggestionDatasource.users as NSArray).filteredArrayUsingPredicate(namePredicate!.predicateWithSubstitutionVariables(["word" : word])) as [User]
        }
    }

However, my User class doesn't subclass NSObject so it's not Key Value Compliant. I get unrecognized selector 'valueForKey' whenever I try this. Is there a way I can make a custom class Key Value Compliant without subclassing NSObject? Or perhaps a way to use NSPredicate without having to use KVC.

Thanks

Answer 1

Aren't you making this awfully unnecessarily hard for yourself? Why not just use what Swift gives you - filter, hasPrefix, and so on? I don't know what a User actually is, but let's pretend it's something like this:

struct User {
    let username : String = ""
}

And let's pretend that users is like this:

let users = [User(username:"Matt Neuburg"), User(username:"Dudley Doright")]

Then what you seem to be trying to do is trivial in Swift:

let word = "Matt"
let users2 = users.filter {$0.username.hasPrefix(word)}