How can I get list Languages from NaturalLanguage

I want to get a list of available languages for text translations. The text is unknown.

I created a simple project:

import SwiftUI
import Foundation
import NaturalLanguage

struct ContentView: View {
    
    func LanguagesList () {
        let allLanguages = Locale.isoLanguageCodes
        let locale = Locale(identifier: "en_US")
        for languageCode in allLanguages {
            if let languageName = locale.localizedString(forIdentifier: languageCode) {
                print("\(languageCode): \(languageName)")
            }
        }
        let recognizer = NLLanguageRecognizer()
        recognizer.
        let textRecognitionLanguages = recognizer.availableRecognitionLanguages(for: .text)
        print(textRecognitionLanguages)
    }
    
    var body: some View {
        VStack {
            Image(systemName: "globe")
                .imageScale(.large)
                .foregroundColor(.accentColor)
            Text("Hello, world!")
            Button("Languages list") {
                LanguagesList()
            }
        }
        .padding()
    }
}

I tried to ask ChatGPT. It claims that this is how it should work (SDK 14, NaturalLanguage version 2.0). I updated the OS.

I have Xcode 14.3 includes Swift 5.8 and SDKs for iOS 16.4, iPadOS 16.4, tvOS 16.4, watchOS 9.4, and macOS Ventura 13.3.

The compiler throws 2 errors:

1. Cannot infer contextual base in reference to member 'text'

2. Value of type 'NLLanguageRecognizer' has no member 'availableRecognitionLanguages'

Is there a way to get a list of available languages for text translations. The text is not known in advance?

(From my comment): As @HangarRash said, availableRecognitionLanguages does not exist. For a full list of NLLanguages, see the docs for the enum: NLLanguage. For many enums, especially ones that you create, there is a useful protocol for looping over all of the cases, which is exactly what you are trying to do above. This protocol, called CaseIterable, is not one that NLLanguage conforms to, but as this Hacking with Swift article says, we can make it conform ourselves. Here is an example of adding this conformance:

extension NLLanguage: CaseIterable {
    public static var allCases: [NLLanguage] {
    [.amharic, .arabic, .armenian, .bengali, .bulgarian, .burmese, .catalan, .cherokee, .croatian, .czech, .danish, .dutch, .english, .finnish, .french, .georgian, .german, .greek, .gujarati, .hebrew, .hindi, .hungarian, .icelandic, .indonesian, .italian, .japanese, .kannada, .kazakh, .khmer, .korean, .lao, .malay, .malayalam, .marathi, .mongolian, .norwegian, .oriya, .persian, .polish, .portuguese, .punjabi, .romanian, .russian, .simplifiedChinese, .sinhalese, .slovak, .spanish, .swedish, .tamil, .telugu, .thai, .tibetan, .traditionalChinese, .turkish, .ukrainian, .urdu, .vietnamese, .undetermined]
    }
    
}

And then we can loop over each case like this:

print(NLLanguage.allCases)
//Prints each and every case

We have to declare this conformance ourselves, which also means we have to update it if Apple releases a new NLLanguage. Here are two examples, one with the code that you provided above, and one displaying a list (via ForEach) of all of the cases. First, for the code you provided above:

import SwiftUI
import Foundation
import NaturalLanguage

struct ContentView: View {
    
    func LanguagesList() {
        for lang in NLLanguage.allCases {
            let locale = Locale(identifier: lang.rawValue)
            if let languageName = locale.localizedString(forIdentifier: lang.rawValue) {
                print("\(lang.rawValue): \(languageName)")
                        }
        }
        print(NLLanguage.allCases.map({ lang in
            lang.rawValue
        }))
        //Or, if you want to print the actual language names, use the following:
//        print(NLLanguage.allCases.map({ lang in
//            Locale.current.localizedString(forIdentifier: lang.rawValue) ?? lang.rawValue
//        }))
    }
    
    var body: some View {
        VStack {
            Image(systemName: "globe")
                .imageScale(.large)
                .foregroundColor(.accentColor)
            Text("Hello, world!")
            Button("Languages list") {
                LanguagesList()
            }
        }
        .padding()
    }
}

And next, a ForEach:

struct LanguagesListView: View {
    var body: some View {
        VStack{
            ForEach(NLLanguage.allCases, id: \.self) { lang in
                Text(Locale.current.localizedString(forIdentifier: lang.rawValue) ?? lang.rawValue)
            }
        }
    }
}

Please note that it is not a good idea to use id: \.self in production, as if two values are the same, this can lead to undefined behavior. Above, I am using Locale because this displays the full String for the language - such as "English", rather than the language identifier "en". If you want to display the raw values, then just pass in lang.rawValue.