anchor.diff:  
   
   %% @private
  -do_parse_key(Key, Val, Parse) ->
  +do_parse_key(Key, Val, #parse{allow_unknown=AllowUnknown}=Parse) ->
        case find_config(Key, Parse) of
            {ok, _Key2, ignore} ->
                {ok, Parse};
  
positive.code:     Parse = #parse{
          syntax = Syntax,
          opts = Opts,
          path = maps:get(path, Opts, <<>>)
      },
      case do_parse(Terms, Parse) of
          {ok, #parse{ok=Ok, no_ok=NoOk}} ->
  
negative.code: -type parse_opts() ::
      #{
          path => binary(),           % Use base path instead of <<>>
          allow_unknown => boolean(),
          term() => term()            % To be used as context in external functions
      }.
  
  