anchor.diff:     | [\u002F-\u00FF]
      ;
      // a single octet other than NUL, CR, LF, double-quote, or backslash
  -   
  +
   OCTETNOTQSPECIAL
      : [\u0001-\u0009]
      | [\u000B-\u000C]
  
positive.code:    | [\u002B-\u00FF]
     ;
     // either a CRLF pair, OR a single octet  other than NUL, CR, LF, star, or slash
     
  ADDRESSPART
     : ':localpart'
     | ':domain'
  
negative.code:    | [\u005D-\u00FF]
     ;
     // either a CRLF pair, OR a single octet other than NUL, CR, LF, or star
  
  NOTSTAR
     : [\u0001-\u0009]
     | [\u000B-\u000C]
  