anchor.diff:    ;
   
   paren_access :
  -     cell_access (FILLER? t_lparen FILLER? (arg_list FILLER?)? t_rparen)?
  +     cell_access (FILLER? t_LPAREN FILLER? (arg_list FILLER?)? t_RPAREN)?
     ;
   
   cell_access :
  -     name (FILLER? t_lcurly FILLER? arg_list FILLER? t_rcurly)*
  +     name (FILLER? t_LCURLY FILLER? arg_list FILLER? t_RCURLY)*
     |  {inParens()}? name FILLER? AT FILLER? name
     |  {!inParens()}? name AT name //TODO-AC: fix error message for name AT FILLER name case
     ;
  
positive.code:   ;
  
  matrix :
       t_lsquare optional_row_list t_rsquare
    ;
  
  cell_array :
       t_lcurly optional_row_list t_rcurly
    ;
  
  optional_row_list :
  
negative.code: 
  primary_expr :
       literal
    |  t_LPAREN FILLER? expr FILLER? t_RPAREN
    |  matrix
    |  cell_array
    |  access
  