anchor.diff:  
   hexadecimalLiterals
       : HEX_DIGIT_
  -    | characterSet_? HEX_DIGIT_ collateClause_?
  +    | characterSetName_? HEX_DIGIT_ collateName_?
       ;
   
   bitValueLiterals
       : BIT_NUM_
  -    | characterSet_? BIT_NUM_ collateClause_?
  +    | characterSetName_? BIT_NUM_ collateName_?
       ;
       
   booleanLiterals
  
positive.code: 
  stringLiterals
      : STRING_
      | characterSet_? STRING_ collateClause_?
      | IDENTIFIER_ STRING_ COLLATE (STRING_ | IDENTIFIER_)?
      ;
  
  
negative.code: 
  nullValueLiterals
      : NULL
      ;
  
  characterSetName_
      : IDENTIFIER_
      ;
  collateName_
      : IDENTIFIER_
      ;
  
  identifier_
  