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(a.josey 14931) Re: (c.harding 44333) Re: regexMatch (Was: substring filters using DN attributes ?)
>Is there a standard definition of what a regular expression actually is ?
>
There certainly is.
It is part of the standard definition of the UNIX(TM) operating system
which is available (foc) from The Open Group, see
http://www.opengroup.org/publications/catalog/t912.htm#medium2
The definition of regular expressions is at
http://www.opengroup.org/onlinepubs/007908799/xbd/re.html
>I ask this because if you work on Solaris for example, there are n different
>libraries and functions for doing regular expression matching so the meaning
>of "regular expression" is not so obvious.
>
>Rob.
>
>"Kurt D. Zeilenga" wrote:
>
>> 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
>
>
>
Regards,
Chris
+++++
========================================================================
Chris Harding
T H E Directory Program Manager
O P E N Apex Plaza, Forbury Road, Reading RG1 1AX, UK
G R O U P Mailto:c.harding@opengroup.org Phone: +44 118 950 8311 x2262
WWW: http://www.opengroup.org Mobile: +44 771 8588820
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