static size_t parseIdentifier( CppToken &tk, const char *beg, const char *end ) {
  while( ( ( beg != end ) && *beg <= ' ' ) ) ++beg;

  if( beg == end ) return 0;

  if( strncmp( beg, "L"", 2 ) { return parseStringLiteralL( tk, beg, end ); }
  if( strncmp( beg, "u"", 2 ) { return parseStringLiteralu( tk, beg, end ); }
  if( strncmp( beg, "U"", 2 ) { return parseStringLiteralU( tk, beg, end ); }

  ...
}

static size_t parseStringLiteralL( CppToken &tk, const char *beg, const char *end ) {
  const wchar_t *wbeg = reinterpret_cast< const wchar_t * >( beg );
  const wchar_t *wend = reinterpret_cast< const wchar_t * >( end );
  ...
}

static size_t parseStringLiteralL( CppToken &tk, const char *beg, const char *end ) {
  std::wstring value;

  while( *beg != '"' ) value.append( 1, utf8_to_wchart( *beg ) );

  ...
}