anchor.diff:  expr :
        short_or_expr
     |  t_AT t_FILLER? input_params t_FILLER? expr
  +  |  t_COLON //really only applies in args, but let Natlab handle that
     ;
   
   short_or_expr :
  
positive.code:   ;
  
  arg_list :  
       (arg) (t_FILLER? t_COMMA t_FILLER? arg)*
    ;
    
  arg :
       expr
    |  t_COLON
    ;
  
  literal :
  
negative.code:   |  cell_array
    |  access
    |  t_AT t_FILLER? name
    |  t_END //really only applies in args, but let Natlab handle that
    ;
  
  access :
  