anchor.diff:    ;
   
   element :
  -     expr
  +     expr_in_array
     ;
   
   //non-empty
  
positive.code:  * to be a column delimiter.
   */
  private boolean isElementSeparator() {
      if(!(inCurly() || inSquare())) {
          return false;
      }
      Token prevToken = input.LT(-1);
      Token nextToken = input.LT(2); //2, not 1 because we haven't matched the FILLER yet
      switch(nextToken.getType()) {
  
negative.code: 
  t_ASSIGN : ASSIGN { offsetTracker.advanceInLine(1); };
  
  t_LPAREN : LPAREN { offsetTracker.advanceInLine(1); };
  t_RPAREN : RPAREN { offsetTracker.advanceInLine(1); };
  t_LCURLY : LCURLY { offsetTracker.advanceInLine(1); };
  t_RCURLY : RCURLY { offsetTracker.advanceInLine(1); };
  t_LSQUARE : LSQUARE { offsetTracker.advanceInLine(1); };
  t_RSQUARE : RSQUARE { offsetTracker.advanceInLine(1); };
  
  t_IDENTIFIER : IDENTIFIER { offsetTracker.advanceByTextSize($text); };
  t_NUMBER : NUMBER { offsetTracker.advanceByTextSize($text); };
  