docs/70507: RE in BUG section of re_format(7) in obsolete notation

[Giorgos Keramidas]

The following reply was made to PR docs/70507; it has been noted by GNATS.

From: Giorgos Keramidas <keramida at freebsd.org>
To: "Daniel C. Sobral" <dcs at newsguy.com>
Cc: Marian Cerny <jojo at matfyz.cz>, bug-followup at freebsd.org,
        "Daniel C. Sobral" <dcs at freebsd.org>, Ruslan Ermilov <ru at freebsd.org>,
        "David O'Brien" <obrien at freebsd.org>
Subject: Re: docs/70507: RE in BUG section of re_format(7) in obsolete notation
Date: Sun, 10 Jul 2005 15:05:55 +0300

 On 2005-07-09 23:01, "Daniel C. Sobral" <dcs at newsguy.com> wrote:
 >Giorgos Keramidas wrote:
 >>On 2004-08-16 01:30, Marian Cerny <jojo at matfyz.cz> wrote:
 >>> Shouldn't this paragraph in BUGS section in manual page of re_format:
 >>>
 >>>    Back references are a dreadful botch, posing major problems for
 >>>    efficient implementations.  They are also somewhat vaguely
 >>>    defined (does `a\(\(b\)*\2\)*d' match `abbbd'?).
 >>>    Avoid using them.
 >>>
 >>> be
 >>>
 >>>    Back references are a dreadful botch, posing major problems for
 >>>    efficient implementations.  They are also somewhat vaguely
 >>>    defined (does `a((b)*\2)*d' match `abbbd'?).
 >>>    Avoid using them.
 >>>
 >>> because `a\(\(b\)*\2\)*d' is in obsolete notation? Or does this bug
 >>> concern only the obsolete REs?
 >>
 >> You're probably right that we should change the syntax to look like a
 >> modern RE.  The basic RE syntax is still used by many utils in the base
 >> system though.  This is probably why the regexp has remained as you see
 >> it now.
 >>
 >> Daniel, Ruslan and David... what do you think?  Is this change ok?
 >
 > Old, OLD messages... This was lost in a number of spams I'm happing to
 > be clearing right now. Thing about back references is... they didn't
 > work with Extended Regex, only with basic Regex, which is the obsolete
 > notation.
 >
 > So I'm guessing the rewritten example wouldn't work, because back
 > references is not supported with that syntax. So, if this change was
 > done, could someone check if back references are actually supported in
 > extended regex (the modern syntax), and, if not, undone this change? :-)
 
 Nothing was changed, since I wasn't sure of what to do.
 
 Thanks for the clarification :-)
 
 Does this mean we can close this PR now?