anchor.diff:  
   list -> open_bracket ']' : build_list(?line('$1'), []).
   list -> open_bracket list_args close_bracket : build_list(?line('$1'), '$2').
  -list -> open_bracket list_args '|' expr close_bracket : build_list(?line('$1'), '$2', ?line('$3'), '$4').
  +list -> open_bracket list_args '|' matched_expr close_bracket : build_list(?line('$1'), '$2', ?line('$3'), '$4').
   
   % Tuple
   
  
positive.code: 
  Nonterminals
    grammar expr_list
    expr call_expr max_expr base_expr block_expr curly_expr
    comma_separator comma_expr
    add_op mult_op unary_op match_op andand_op oror_op
    open_paren close_paren
    open_bracket close_bracket
    open_curly close_curly
    call_args call_args_parens call_args_no_parens
    base_orddict kv_comma kv_eol
    do_eol end_eol kv_list do_block curly_block
    list list_args
    dot_op dot_identifier dot_paren_identifier dot_punctuated_identifier dot_call_expr
  
negative.code: Rootsymbol grammar.
  
  Right     20 match_op.
  Left      30 do.
  Left      40 ','.  % Solve nested call_args conflicts
  
  Left      50 oror_op.
  