CleanKeys.swift

///
/// Swift script to parse, find & replace a set of values with corresponding keys
/// from a given file.
/// In this case for example it's used to replace strings in `"my.String".localized()`
/// with their R.swift generated counterparts.
/// 
/// How to use:
/// - copy the script into the project root folder
/// - set permissions: `chmod -R +x CleanKeys.swift`
/// - run: `./CleanKeys.swift`
/// - ??
/// - profit
///
/// Disclamer: for ease of use, the entire block of code from R.generated.swift containing the keys
/// `static let myStringKey = Rswift.StringResource......` has been copied inside a file `generatedKeys.txt`
/// in the same folder of this script. An example is attached to this gist.

#!/usr/bin/env swift

import Foundation

let dirPath = FileManager.default.currentDirectoryPath
let generatedKeyPath = "/generatedKeys.txt"
let thisFileName = "CleanKeys.swift"

func getContentOfFile(at path: String) -> String {
    let keyFilesPath = dirPath + path
    do {
        let contents = try String(contentsOfFile: keyFilesPath)
        return contents
    } catch {
        print("error reading file!! \(error.localizedDescription)")    
        return ""
    }
}

func writeNewContentToFile(at path: String, newContent: String) {
    let fileURL = URL(fileURLWithPath: dirPath + path)
    do {
        try newContent.write(to: fileURL, atomically: true, encoding: .utf8)
    }
    catch { 
        print("error writing file!! \(error.localizedDescription)")
    }
}

func getKeys(from content: String) -> [(key: String, value: String)] {
    let lines = content
        .components(separatedBy: "\n")
        .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
        .filter { $0.starts(with: "static") }

    let keys = lines
        .map { line -> (String, String) in
            let components = line.components(separatedBy: " ")
            let key = components[2]
            let value = components[5]
                .replacingOccurrences(of: "\"", with: "")
                .replacingOccurrences(of: ",", with: "")
            return (key, value) 
        }

    return keys
}

func getProjectSwiftFilesPaths() -> [String] {
    let enumerator = FileManager.default.enumerator(atPath: dirPath)
    let filePaths = (enumerator?.allObjects as! [String])
        .filter{ $0.contains(".swift") && $0 != thisFileName }
        .map { "/" + $0 }
    return filePaths
}

func replaceInFile(path: String, keys: [(key: String, value: String)]) {
    var contentOfFile = getContentOfFile(at: path)
    guard !contentOfFile.isEmpty else { return }
    guard keys.map(\.value).contains(where: contentOfFile.contains) else { 
        print("File does not contain relevant values, skipping")
        return
    }

    let valuesToReplace = keys.filter { contentOfFile.contains($0.value) }

    valuesToReplace.forEach {
        let oldValueFormat = "\"\($0.value)\".localized()"
        let newKey = "R.string.localizable.\($0.key)()"

        contentOfFile = contentOfFile.replacingOccurrences(of: oldValueFormat, with: newKey)
        print("\(path) - replaced: \($0.value)")
    }

    writeNewContentToFile(at: path, newContent: contentOfFile)
}

func main() {
    let content = getContentOfFile(at: generatedKeyPath)
    let keys = getKeys(from: content)
    let files = getProjectSwiftFilesPaths()
    
    files.forEach { file in
        replaceInFile(path: file, keys: keys)
    }
}

main()

generatedKeys.txt

/// This is a block of code directly from R.generated.swift 

      /// en translation: 
      ///
      /// Locales: es, en
      static let myLocalizedKey = Rswift.StringResource(key: "my.localized.key", tableName: "Localizable", bundle: R.hostingBundle, locales: ["es", "en"], comment: nil)
      /// en translation:  
      ///
      /// Locales: es, en
      static let reminderTitle18 = Rswift.StringResource(key: "reminder.title.18", tableName: "Localizable", bundle: R.hostingBundle, locales: ["es", "en"], comment: nil)
      /// en translation:  
      ///
      /// Locales: es, en
      static let reminderTitle12 = Rswift.StringResource(key: "reminder.title.12", tableName: "Localizable", bundle: R.hostingBundle, locales: ["es", "en"], comment: nil)