code: private function getDefaultPatternList()
      {
          static $patterns = null;
          if (!isset($patterns)) {
              $fixed4   = "\\d{4}";
              $fixed2   = "\\d{2}";
              $var2     = "[1-5][0-9]|[0-9]";
              $varM     = "1[0-2]|[1-9]";
              $varD     = "3[0-1]|[1-2][0-9]|[0-9]";
              $varH     = "2[0-4]|1[0-9]|[0-9]";
              $patterns = array(
                  "Y" => new Numbers("year",   $fixed4),
                  "m" => new Numbers("month",  $fixed2),
                  "n" => new Numbers("month",  $varM),
                  "d" => new Numbers("date",   $fixed2),
                  "j" => new Numbers("date",   $varD),
                  "H" => new Numbers("hour",   $fixed2),
                  "G" => new Numbers("hour",   $varH),
                  "i" => new Numbers("minute", $fixed2),
                  "f" => new Numbers("minute", $var2),
                  "s" => new Numbers("second", $fixed2),
                  "b" => new Numbers("second", $var2),
              );
          }
          return $patterns;
      }
docs: パターン一覧を返します.
  キーが変換文字, 値がその文字に対応する Pattern オブジェクトとなります.
  
  @return array
  @codeCoverageIgnore