regexMatch (Was: substring filters using DN attributes ?)

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

At 09:35 AM 7/25/00 -0700, Mark C Smith wrote:
>"Kurt D. Zeilenga" wrote:
>>
>> I've meaning to publish a regexMatch rule I-D which would allow
>> matching of an asserted regular expression against the string
>> representation of attribute values.  Of course, to be useful with
>> DNs, we'd have to have to define a canonical string representation
>> of DNs.  Given such, you would be able to do DN matching like:
>> 
>>         (member:regexMatch:=.*,dc=example,dc=com$)
>> 
>> Such a matching rule, I believe, would be generally useful in
>> a number of applications.  Of course, user applications may
>> not want to expose regular expressions to average Joe.
>> 
>> If others concur that this would be generally useful, I'll put
>> up a straw man proposal after IETF#48.
>
>It would be interesting to see examples of the kinds of LDAP application
>problems that would be more easily addressed if such a matching rule was
>available.

I agree.  In fact, I wouldn't attempt to write such an I-D
without decent examples.  In general, such a rule would be useful
to applications which required very specific, complex matching
which cannot easily be decomposed into a substrings assertion.
I'll try to come up with some examples, hopefully ones which
are not too contrived.

>If all we really need is a way to anchor the start and end
>of strings (i.e., ^ and $ from regex), I'd rather see a more narrow
>proposal.  Why?  Because general regular expression matching will be
>quite difficult to support using indexes, etc.

I concur that general regular expressions are quite difficult to
to support using indexing.  I also concur that applications wanting
to make an assertion should use an appropriate matching rule.  I
fully agree that applications wanting to simply assert start/end
text should use a substrings matching rules.

Kurt