Localised Strings in addition to currentLocale

[uny]

I would like to use localized strings in addition to NSLocale.currentLocale().

Pattern 1:

struct string {
  struct localizable {
    let locale: NSLocale
    init(locale: NSLocale = NSLocale.currentLocale()) {
      self.locale = locale
    }
    /// Locales: en, ja
    static func helloWorld() -> String {
        return String(format: NSLocalizedString("HelloWorld", comment: ""), locale: self.locale)
    }
  }
}

Pattern 2:

struct string {
  struct en {
    /// Locales: en, ja
    static func helloWorld() -> String {
        return String(format: NSLocalizedString("HelloWorld", comment: ""), locale: NSLocale(localeIdentifier: "en"))
    }
  }
}

[tomlokhorst]

Hey, thanks for creating this issue!

I do plan on adding a feature to R.string for requesting a localized string in a specific locale. Currently, it always chooses the preferred localization.

For now, it's possible to use the generated StringResource to get the strongly typed key for a localized string. You can do something like this:

let basePath = NSBundle.mainBundle().pathForResource("Base", ofType: "lproj")!
let nlPath = NSBundle.mainBundle().pathForResource("nl", ofType: "lproj")!
let baseBundle = NSBundle(path: basePath)!
let nlBundle = NSBundle(path: nlPath)!

let baseTripsTitle = baseBundle.localizedStringForKey(R.string.planner.tripsTitle.key,
  value: nil,
  table: R.string.planner.tripsTitle.tableName)

let dutchTripsTitle = nlBundle.localizedStringForKey(R.string.planner.tripsTitle.key,
  value: nil,
  table: R.string.planner.tripsTitle.tableName)

[uny]

Thank you!
Currently, I am doing the same as your suggestion.

I need time to read and understand the code, but I would like to contribute when I can.
Do you have any idea to implement this feature (pattern 1, pattern 2, or others)?

[mbesnili]

Any progress on this issue ? Maybe you can give some ideas about how this feature should be implemented, so that someone else can be implemented.

[tomlokhorst]

I haven't taken the time to think about this more, since I don't need this at the moment.

The project I'm currently working on does need localised strings for a specific locale, but it's still a few months before we'll start working on that feature.

If someone wants to work on this feature before that, feel free to start a PR or comment on this issue with your ideas.

Related: #155

[tomlokhorst]

I'm working on a design for this feature. It will probably be implemented after #244 and #155.

I think there are two use cases for this, which we can both support:

1. R.swift should have static references to all localizations for which a string is available (can be different per strings file).
   This could be something like: R.string.settings.en.title() (english title) or R.string.settings.nl.title() (dutch title)
2. Get a localized string in a different localization from the preferred localization which NSLocalizedString uses by default.
   This could be something like: R.string.settings.title(locale: NSLocale(localeIdentifier: "fr-CA")) (french title)

With that last use case, I think we should make sure R.swift uses the same fallback logic as NSLocalizedString uses internally. I.e. if a 'en' and 'fr' translation is available, and the users requests 'fr-CA', it should fallback to 'fr'.
I don't think this fallback code is accessible (or open sourced) at this time.

Note that none of this is specific to strings, we could do this for all localized resources.

[tomlokhorst]

I've discussed this some more with @mac-cain13, our conclusions so far:

The use cases for static reference to specific locales are small, so this doesn't need to be a top-level API.
Instead of R.string.settings.nl.title(), we can do something like: R.string.settings.title(locale: .nl). Where the '.nl' is a case of an enum specifically generated for the Settings.strings file.

Replicating the complete fallback mechanism of NSLocalizedString is complex, but that can be done outside the scope of this API. If we simply take an array of possible locales, we can use that to fallback, the order can be generated externally, e.g.:
R.string.settrings.title(locales: ["en", "fr", "nl"])

The simplest, most straightforward API, that can also be used for images and the like, is simply an extra argument as the last argument of the generated function.
R.string.settrings.numberOfItemsProgress(current: 1, total: 3, locale: "es")
R.image.logo(compatitibleWith: traitCollection, locale: "zh")

[fruitcoder]

Is there any progress on this or another convenient way to inject the locale? The solution you described on 20 May 2016 could be put in an extension but it seems like a lot of overhead.

[uny]

Sorry, no progress for me...

[fruitcoder]

Wouldn't it work to overload the static localizable functions with the locale like

static func someLocalizedString(withParam value1: Int, preferredLocale locale: Locale? = nil) -> String {
  let bundle = locale?.languageCode.flatMap {
    Bundle.main.path(forResource: $0, ofType: "lproj").flatMap {
      Bundle(path: $0)
    }
  } ?? R.hostingBundle

  return String(format: NSLocalizedString("SomeLocalizedStringKey", bundle: bundle, value: "String %#@param@", comment: ""), locale: locale ?? R.applicationLocale, value1)
}