anchor.diff:      ;
   
   role
  -    : ID
  +    : STRING AT_ STRING
       | STRING
  -    | STRING AT_ STRING
  +    | ID
       ;
   
   roles
  
positive.code: //create-user.html
  createUser
      : CREATE USER (IF NOT EXISTS)?
      user authOptions
      DEFAULT ROLE roles
      (REQUIRE (NONE | tlsOption (COMMA AND? tlsOption)*))?
      (WITH resourceOption (COMMA resourceOption)*)?
  
negative.code:     ;
  
  user
      : STRING AT_ STRING
      | STRING
      | ID
      ;
  
  users
  