 
 enum AsciifyLetterMode { case regular, lowercase, uppercase }
 
+func lowercased(letter : Character) -> Character {
+  let s = String(letter);
+  return s.lowercased()[s.startIndex];
+}
+
+func uppercased(letter : Character) -> Character {
+  let s = String(letter);
+  return s.uppercased()[s.startIndex];
+}
+
 func asciify(letter : Character, mode : AsciifyLetterMode)
-            -> Character {
+            -> Character? {
   if let r = asciiRepresentations[letter] {
     switch (mode) {
       case .regular:   return r;
-      case .lowercase: return r.capitalized();
-      case .uppercase: return r.();
+      case .lowercase: return lowercased(letter: r);
+      case .uppercase: return uppercased(letter: r);
     }
   }
-  return letter;
+  return nil;
 }
 
 func toggleAccent(letter : Character) -> Character {

  while (i < s.characters.count &&
  !space && index < asciiString.characters.count) {
    currentChar = charAt(s: turkishString, i: index);
  }
}

import patterns

let asciiRepresentations : [Character: Character] = [
  "ç": "c",
  "Ç": "C",
