anchor.diff:    ;
   
   colon_expr :
  -     plus_expr (t_FILLER? t_COLON t_FILLER? plus_expr (t_FILLER? t_COLON t_FILLER? plus_expr)?)?
  -  ;
  +     plus_expr  ;
     
   plus_expr :
  -     binary_expr (t_FILLER? (t_PLUS | t_MINUS) t_FILLER? binary_expr)*
  +     binary_expr
     ;
   
   binary_expr :
  
positive.code: expr :
       short_or_expr
    |  t_AT t_FILLER? input_params t_FILLER? expr
    ;
  
  short_or_expr :
  
negative.code:   |  cell_array
    |  access
    |  t_AT t_FILLER? name
    |  t_END //really only applies in args, but let Natlab handle that
    ;
  
  access :
  