Re: Subject header matching--once again

["Andrew J. Gray" <andrewg@gnu.org>]

> In the meantime the existing Subject match code should be fixed to reflect
> the agreement reached a year back, see my first mail in this thread:
> http://mail.gnu.org/pipermail/help-gnats/2002-November/003185.html
> 
> A patch follows that includes an update to the documentation. The feature
> is mentioned a couple of times in passing in 'Keeping Track'. I think it
> deserves a (sub)section of its own and have inserted one called 'Following up
> via direct email' in the 'Editing existing Problem Reports' section of 'The
> GNATS User Tools' chapter. I have also corrected a couple of minor errors
> that I ran across.

Thanks for that patch, I am sorry it has taken me so long to get to
it.

> The regular expression used for matching the Subject line appears in the code
> as
> 
>      \\<(PR[ \t#/]?|([-A-Za-z0-9_+.]+)/)([0-9]+)
> 
> whereas the documentation has
> 
>      \<(PR[ \t#/]?|[-\w+.]+/)[0-9]+
> 
> I couldn't get the GNU match-word-constituent operator (\w) to work inside
> the bracket expression and am uncertain as to whether it is allowed there.
> Perl has it. The parentheses which are in the code, but missing from the
> manual, do not affect the matching; they are there only to capture Category
> and Number.

As I understand it the match-word-constituent operator (\w) is not
meant to work inside matching lists. I am looking at the "info"
documentation included with the regex 0.12 (available from
http://ftp.gnu.org/pub/gnu/regex/regex-0.12.tar.gz). In the "List
Operators" node it says most characters lose any special meaning
inside a list.

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?

> I haven't aligned the regular expression syntax with the rest of GNATS as
> suggested by Milan. This is a non-issue as long as the regular expression
> is hard-coded and not exposed for users to modify. The regex searching is also
> case sensitive now.

OK.

> The patch is in production use in the GNATS installation that I am
> responsible for. I hope it can make it into GNATS 4.0-beta2?

Sorry that the patch missed the beta 2. Once we have decided whether
or not to use the alnum character class I will commit the patch.

-- 
Andrew J. Gray


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