title: How to check if a character is a letter of some alphabet?
body: <p>How to check in C++ if a character is a letter of some alphabet?
  Generally I need something like this:</p>
  
  <pre><code>bool is_german(wchar_t ch);
  bool is_russian(wchar_t ch);
  bool is_japanese(wchar_t ch);
  </code></pre>
  
  <p>and etc.</p>
  
  <p><strong>EDIT 1</strong>. Can I do it without defining all charachter sets of all languages I need. Or maybe there is some library which has somethis like this:</p>
  
  <blockquote>
    <p>std::vector alphabet = GetEnglishAlphabet(); // alphabet =
    {L'a', L'b', L'c', ...}</p>
  </blockquote>
  
  <p><strong>EDIT 2</strong>. If someone is interested in I've found </p>
  
  <blockquote>
    <p>Script QChar::script() const</p>
  </blockquote>