ietf-nntp OVER and PAT

Clive D.W. Feather clive at demon.net
Wed Nov 22 03:07:00 PST 2000


Russ Allbery said:
>> I think the concern was that the result isn't either predictable or
>> convenient for a client. For example, the following headers:
> 
>>     Subject: Re: This is a test header
> 
>>     Subject: Re: This is a
>>         test header
> 
>> should be equivalent,
> 
> Why do you feel that those to headers should be equivalent?  DRUMS
> explicitly says that they're not.

Because I misremembered the folding rules.

> *Ideally*, I'd like to use exactly the above definition of unfolding for
> overview data and then additionally convert any tab to a space and
> otherwise not make any changes to the header (headers containing lone NUL,
> CR, or LF should really be rejected, but if we want to be complete, we
> could say that those three characters are also replaced with space if
> present).  I think we should be able to preserve all the other control
> characters.

I don't have the experience to argue one way or another about this, but see
below.

>> and I want to write a single wildmat that matches either. Personally I'd
>> also like to be able to match:
> 
>>     Subject: Re:  This is a test header
> 
>> as well.
> 
> I think we're getting towards regular expressions here, honestly.  Maybe
> PAT is an inherently bad idea and what we really want to do is standardize
> XHDR and introduce a separate command that uses regexes.  Bleh.

The client can always do further filtering on the results, perhaps with
full regexes, so I don't see much need for them in the server.

However, white space *is* something that gets munged a lot in practice,
whether or not we approve of this. At present I have no way to pick out
headers containing consecutive words *allowing for white space hassles*
other than "consecutive*word" or "consecutive\u0040*word", which isn't
really what I need. I think that a \s matching white space sequences is a
reasonable addition.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:  +44 20 8371 1138
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