anchor.diff:  	{Req#http_req.raw_path, Req}.
   
   -spec qs_val(Name::string(), Req::#http_req{})
  -	-> {Value::string() | true, Req::#http_req{}}.
  +	-> {Value::string() | true | undefined, Req::#http_req{}}.
   qs_val(Name, Req=#http_req{raw_qs=RawQs, qs_vals=undefined}) ->
   	QsVals = parse_qs(RawQs),
   	qs_val(Name, Req#http_req{qs_vals=QsVals});
   qs_val(Name, Req) ->
  -	{Name, Value} = lists:keyfind(Name, 1, Req#http_req.qs_vals),
  -	{Value, Req}.
  +	case lists:keyfind(Name, 1, Req#http_req.qs_vals) of
  +		{Name, Value} -> {Value, Req};
  +		false -> {undefined, Req}
  +	end.
   
   -spec qs_val(Name::string(), Default::term(), Req::#http_req{})
   	-> {Value::string() | term() | true, Req::#http_req{}}.
  
positive.code: 	{Req#http_req.raw_qs, Req}.
  
  -spec binding(Name::atom(), Req::#http_req{})
  	-> {Value::string(), Req::#http_req{}}.
  binding(Name, Req) ->
  	{Name, Value} = lists:keyfind(Name, 1, Req#http_req.bindings),
  	{Value, Req}.
  
  -spec binding(Name::atom(), Default::term(), Req::#http_req{})
  	-> {Value::string() | term(), Req::#http_req{}}.
  
negative.code: 	{Req#http_req.bindings, Req}.
  
  -spec header(Name::atom() | string(), Req::#http_req{})
  	-> {Value::string() | undefined, Req::#http_req{}}.
  header(Name, Req) ->
  	case lists:keyfind(Name, 1, Req#http_req.headers) of
  		{Name, Value} -> {Value, Req};
  		false -> {undefined, Req}
  	end.
  
  -spec header(Name::atom() | string(), Default::term(), Req::#http_req{})
  