Re: #168: understanding CC directives

On 3/06/2010 7:06 p.m., Mark Nottingham wrote:
> On 02/06/2010, at 6:45 PM, Julian Reschke wrote:
> Furthermore, the BNF doesn't make it clear that request and response 
> directives shouldn't be intermixed;
>>>     Cache-Control-v = 1#cache-directive
>>>     cache-directive = cache-request-directive
>>>         / cache-response-directive
>> That could be addressed by saying:
>>      Cache-Control-v = 1#cache-request-directive
>>                      / 1#cache-response-directive
>> However, I'm not sure we need to express this as a syntactical constraint (and it also might confuse people with respect to whether this header uses the "list style" or not).
> Yes; I'm not sure we can really do anything about this, except make sure it's clear in the prose.

hang on a minute.  The existing BNF is logically incorrect, the proposed 
replacement is logically correct, but we worry about confusion?

I think it's more likely to create implementor confusion by having the 
ABNF disagree with the prose.  It should still be clear to anyone that 
the choice is between a list of request directives or a list of response 

Maybe the problem is that in fact the Cache-control request header is 
different to the Cache-control response header.  You shouldn't put the 
Cache-control request header in a response message and vice-versa.

Probably going to far to solve that one though, since it would require 
something like

Cache-control-v = Cache-control-req / Cache-control-resp
Cache-control-req = 1#cache-request-directive
Cache-control-resp = 1#cache-response-directive


> Cheers,
> --
> Mark Nottingham

Adrien de Croy - WinGate Proxy Server -

Received on Monday, 7 June 2010 12:26:02 UTC