anchor.diff:  
   t_ASSIGN : ASSIGN { offsetTracker.advanceInLine(1); };
   
  -t_LPAREN : LPAREN { offsetTracker.advanceInLine(1); bracketStack.push(LPAREN); };
  -t_RPAREN : RPAREN { offsetTracker.advanceInLine(1); bracketStack.pop(); };
  -t_LCURLY : LCURLY { offsetTracker.advanceInLine(1); bracketStack.push(LCURLY); };
  -t_RCURLY : RCURLY { offsetTracker.advanceInLine(1); bracketStack.pop(); };
  -t_LSQUARE : LSQUARE { offsetTracker.advanceInLine(1); bracketStack.push(LSQUARE); };
  -t_RSQUARE : RSQUARE { offsetTracker.advanceInLine(1); bracketStack.pop(); };
  +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); };
  
positive.code:   |  matrix
    |  cell_array
    |  access
    |  t_AT t_FILLER? name
    ;
  
  
negative.code:  * to be a column delimiter.
   */
  private boolean isElementSeparator() {
      Token prevToken = input.LT(-1);
      Token nextToken = input.LT(2); //2, not 1 because we haven't matched the FILLER yet
      switch(nextToken.getType()) {
  