Re: Subject header matching--once again

[Lars Henriksen]

On Sun, Mar 02, 2003 at 12:46:47PM -0800, Mark D. Baushke wrote:
> Andrew J. Gray <address@hidden> writes:
> > I think the closest equivalent that works in a list is the alnum
> > character class. Using this the regular expression would become:
> > 
> >     \\<(PR[ \t#/]?|([-[:alnum:]_+.]+)/)([0-9]+)
> > 
> > Do you think this is a satisfactory replacement for \w?
> 
> \w is the same as [:alnum:]_ and does not really have "-" in the list,
> but doesn't have or "." or "+" in it. That said, using
> 
> ([-:[:alnum:]_+.]+) in the above would seem to match a category name
> properly.

Hmm. Category names definitely cannot contain a colon (the field separator
in the categories file). This made me wonder: which characters _are_ really
forbidden/allowed? The manual (section 4.4.1) has a long list of characters
that cannot appear in a category name, and is a bit woolly about comma.
Forward slash is not mentioned, but ruled out since a category name is also
a directory name. The following are implicitly allowed: # % = ? @ \ ^ |,
but why?

Probably the manual (and the code) should have a list of allowed characters,
viz. those allowed by the regex above.

Lars Henriksen