From owner-freebsd-hackers@FreeBSD.ORG Wed Feb 10 18:42:33 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 592CF1065679 for ; Wed, 10 Feb 2010 18:42:33 +0000 (UTC) (envelope-from des@des.no) Received: from smtp.des.no (smtp.des.no [194.63.250.102]) by mx1.freebsd.org (Postfix) with ESMTP id 193508FC18 for ; Wed, 10 Feb 2010 18:42:32 +0000 (UTC) Received: from ds4.des.no (des.no [84.49.246.2]) by smtp.des.no (Postfix) with ESMTP id E31291FFC22; Wed, 10 Feb 2010 18:42:31 +0000 (UTC) Received: by ds4.des.no (Postfix, from userid 1001) id B23B3844A1; Wed, 10 Feb 2010 19:42:31 +0100 (CET) From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= To: Garrett Cooper References: <86tytqvwky.fsf@ds4.des.no> <26049703-8844-4476-B277-776A4EFC0A53@gmail.com> <86fx59jpti.fsf@ds4.des.no> <7d6fde3d1002100923i6bbc24a7ocaf408f4d78ec59f@mail.gmail.com> Date: Wed, 10 Feb 2010 19:42:31 +0100 In-Reply-To: <7d6fde3d1002100923i6bbc24a7ocaf408f4d78ec59f@mail.gmail.com> (Garrett Cooper's message of "Wed, 10 Feb 2010 09:23:01 -0800") Message-ID: <868wb1hqzs.fsf@ds4.des.no> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.95 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Cc: Andrew Brampton , freebsd-hackers@freebsd.org Subject: Re: sysctl with regex? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Feb 2010 18:42:33 -0000 Garrett Cooper writes: > Dag-Erling Sm=C3=B8rgrav writes: > > A glob pattern can be trivially translated to a regular expression, but > > not the other way around. =C2=A0Basically, * in a glob pattern correspo= nds to > > [^/]*, ? corresponds to ., and [abcd] and [^abcd] have the same meaning > ^^^^ ???? ^^^^ > The former is a positive assertion, where the latter is a negative > assertion -- how can they have the same meaning? Read the entire sentence. BTW, neither of these are assertions, and neither of these is negative in any sense, they are just different ways of selecting characters from the alphabet (in the extended sense). > > as in a regular expression. =C2=A0The glob pattern syntax has no equiva= lent > > for +, ?, {m,n}, (foo|bar), etc. > > +, {}, and () -- no... that's typically an extension to shell expanded > values (IIRC). ? I can't make sense of this - I'm not sure whether you misunderstood what I wrote, or just failed to express yourself clearly... > > Finally, .* and .+ are *both* greedy. =C2=A0Perl's regular expression s= yntax > > includes non-greedy variants for both (.*? and .+? respectively). > Yes, but I didn't explicitly note those forms. No, but you claimed that .+ is not non-greedy, which is incorrect. DES --=20 Dag-Erling Sm=C3=B8rgrav - des@des.no