[NNTP] wildmat-exact

Charles Lindsey chl at clerew.man.ac.uk
Fri May 6 04:48:57 PDT 2005


In <20050505085035.GE57289 at finch-staff-1.thus.net> "Clive D.W. Feather" <clive at demon.net> writes:

>Charles Lindsey said:
>> In draft26.pre-1.txt I find
>> 
>>      wildmat = wildmat-pattern *("," ["!"] wildmat-pattern)
>>      wildmat-pattern = 1*wildmat-item
>>        ; must not begin with "!" if not immediately preceded by "!"

Ah! I had missed the significance of that disambiguating sentence.

>>      wildmat-item = wildmat-exact / wildmat-wild
>>      wildmat-exact = %x21-29 / %x2B / %x2D-3E / %x40-5A / %x5E-7E /
>>           UTF8-non-ascii ; exclude * , ? [ \ ]
>>      wildmat-wild = "*" / "?"
>> and
>>      newsgroup-name = 1*wildmat-exact
>> 
>> So it seems to me that a wildmat-exact (and hence a newsgroup-name) can
>> contain (and in particular start with) a '!'.

>Yes.

>We wanted wildmats to be as general as possible so that they could be used
>in other commands in the future. That's why they are allowed to contain
>characters like " and !. When we started there was a command that used
>wildmats against headers.

OK, I had forgotten all the previous exchanges on this (it was a long time
ago). However, I am still unhappy, especially as wildmats are now used
only for filtering newsgroup-names.

Suppose, for the sake of argument, that '!' were a permitted character in
newsgroup-names (despite prohibitions to the contrary in RFC 1036 and
Usefor). Then the following newsgroup-names could legitimately exist.

    !foo.bar
    foo.bar
    foo.baz
    bar.foo

So the wildmat "!foo.bar" matches "!foo.bar", "foo.baz" and "bar.foo", and
"!!foo.bar" matches "foo.bar", "foo.baz" and "bar.foo". You can have great
fun working out other interesting effects.

However, I can see no way to write a wildmat that matches "!foo.bar" and
nothing else.

So it seems that I cannot call NEWNEWS on just that group or, more
importantly, I cannot write a news or nntp URI that opens just that one
group, since <news:!foo.bar> will give me access to just about every group
available on the server :-( .

Life would be simpler if '!' was simply excluded from wildmat-exact.

>On 1st May 2001 you proposed removing it and I said that was "too minimal".
>I can't find any further comments in the archives. However, if we're going
>to change this from the then-consensus, such as it was, we need to discuss
>it first.

OK. Discussion please.

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131 Fax: +44 161 436 6133   Web: http://www.cs.man.ac.uk/~chl
Email: chl at clerew.man.ac.uk      Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
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