半角空白を含んだコメント - 3.2.3. Folding white space and comments クォートされた文字列 - 3.2.5. Quoted strings メールアドレス関連 - 3.4. Address Specification DQUOTEは「"」 BFNメモ. 3.2.1. Primitive Tokens NO-WS-CTL = %d1-8 / ; US-ASCII control characters %d11 / ; that do not include the %d12 / ; carriage return, line feed, %d14-31 / ; and white space characters %d127 text = %d1-9 / ; Characters excluding CR and LF %d11 / %d12 / %d