             }
         }
         
+        /// Add a custom FTS5 tokenizer.
+        ///
+        ///     class MyTokenizer : FTS5CustomTokenizer { ... }
+        ///     db.add(tokenizer: MyTokenizer.self)
         public func add<Tokenizer: FTS5CustomTokenizer>(tokenizer: Tokenizer.Type) {
             guard let api = FTS5.api(self) else {
                 fatalError("FTS5 is not enabled")

    }
    
    extension Database {
        private class FTS5TokenizerConstructor {
            let db: Database
            let constructor: (Database, [String], UnsafeMutablePointer<OpaquePointer?>?) -> Int32

    }
    
    extension DatabaseQueue {
        
        // MARK: - Custom FTS5 Tokenizers
        
        /// Add a custom FTS5 tokenizer.
        ///
        ///     class MyTokenizer : FTS5CustomTokenizer { ... }
        ///     dbQueue.add(tokenizer: MyTokenizer.self)
        public func add<Tokenizer: FTS5CustomTokenizer>(tokenizer: Tokenizer.Type) {
            inDatabase { db in
                db.add(tokenizer: Tokenizer.self)
