anchor.diff:  HEALTH_CHECK_TIMEOUT:                  'HEALTH_CHECK_TIMEOUT';
   HIGH:                                  'HIGH';
   HONOR_BROKER_PRIORITY:                 'HONOR_BROKER_PRIORITY';
  -HOURS:                                 'HOURS'; 
  +HOURS:                                 'HOURS';
   IDENTITY_VALUE:                        'IDENTITY_VALUE';
   IGNORE_NONCLUSTERED_COLUMNSTORE_INDEX: 'IGNORE_NONCLUSTERED_COLUMNSTORE_INDEX';
   IMMEDIATE:                             'IMMEDIATE';
  
positive.code: RESERVE_DISK_SPACE:                    'RESERVE_DISK_SPACE';
  RESOURCE:                              'RESOURCE';
  RESOURCE_MANAGER_LOCATION:             'RESOURCE_MANAGER_LOCATION';
  RESTRICTED_USER:                       'RESTRICTED_USER'; 
  RETENTION:                             'RETENTION';
  ROBUST:                                'ROBUST';
  ROOT:                                  'ROOT';
  
negative.code: fragment DEC_DIGIT:    [0-9];
  
  fragment FullWidthLetter
      : '\u00c0'..'\u00d6'
      | '\u00d8'..'\u00f6'
      | '\u00f8'..'\u00ff'
      | '\u0100'..'\u1fff'
      | '\u2c00'..'\u2fff'
      | '\u3040'..'\u318f'
      | '\u3300'..'\u337f'
      | '\u3400'..'\u3fff'
      | '\u4e00'..'\u9fff'
      | '\ua000'..'\ud7ff'
      | '\uf900'..'\ufaff'
      | '\uff00'..'\ufff0'
      // | '\u10000'..'\u1F9FF'  //not support four bytes chars
      // | '\u20000'..'\u2FA1F'
  