[NNTP] wildmat-exact

[Peter Robinson]

|      wildmat = wildmat-pattern *("," ["!"] wildmat-pattern)
|      wildmat-pattern = 1*wildmat-item
|        ; must not begin with "!" if not immediately preceded by "!"
|      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

Charles Lindsey said:

> In <1gw5yas.10gs6ua41nlw0M%pmrobinson at gmx.net> pmrobinson at gmx.net
> (Peter Robinson) writes:
> 
> >Charles Lindsey said:

> >> 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.
> 
> >Actually, assuming the disambiguating comment was normative, neither of
> >those are valid wildmats according to this spec.  You'd have to have
> >something like "a,!foo.bar" and "a,!!foo.bar".  Is there a good reason
> >why we don't have the following: ?
> 
> >        wildmat = ["!"] wildmat-pattern *("," ["!"] wildmat-pattern)
> >                  ^^^^^
> 
> I believe the disambigating comment was intended to be normative (and if
> it wasn't and if it stays, then that would need to be fixed).
> 
> You are right about my examples being invalid, but similar absurdities
> would arise with the forms "a,!foo.bar" and "a,!!foo.bar",

Yes they would.

[...]

> As to allowing a '!' before the first comma, the intention was evidently
> to establish the universe within which the exclusions were then to be
> made.

I see.

> It fails to do so, of course, because if you want the effect of "all
> non-comp.* groups", you can still write "*,!comp.*", even if you cannot
> write "!comp.*".

Yes you can.  But worse, I'd say it "fails to do so" because you can
prefix any valid wildmat with 'not-the-universe,!*,' without altering
its meaning.

> However, the former makes it clearer to the human reader
> what you are trying to do, so I have no wish to change it.

OK.  Leaving it as it is doesn't restrict functionality in any way, so
I'll drop it.

Regards,

Peter