anchor.diff:  exprRecursive
       : matchNone
       ;
  -    
  +
   booleanPrimary
       : booleanPrimary IS NOT? (TRUE | FALSE | UNKNOWN |NULL)
       | booleanPrimary SAFE_EQ predicate
  
positive.code:     ;
  
  columnNamesWithParen
      : LEFT_PAREN columnNames RIGHT_PAREN
      ;
  
  columnNames
      : columnName (COMMA columnName)*
      ;
      
  columnList
      : LEFT_PAREN columnNames RIGHT_PAREN
      ;
  
  indexNames
  
negative.code:     : IF NOT EXISTS;
  
  dataTypeLength
      : LP_ (NUMBER (COMMA NUMBER)?)? RP_
      ;
  
  nullNotnull
  