GNU bug report logs - #74065
documentation suggestion for caret

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Greg Minshall <minshall <at> umich.edu>
To: bug-sed <at> gnu.org
Subject: documentation suggestion for caret
Date: Mon, 28 Oct 2024 09:13:34 -0700

in the info node
----
5.3 Overview of basic regular expression syntax
----

in the discussion of caret (^), there is this (totally correct, afaik)
text:
----
     ‘^’ acts as a special character only at the beginning of the
     regular expression or subexpression (that is, after ‘\(’ or ‘\|’).
     Portable scripts should avoid ‘^’ at the beginning of a
     subexpression, though, as POSIX allows implementations that treat
     ‘^’ as an ordinary character in that context.
----

on the other hand, POSIX *EREs* allow caret in a subexpression.  this
isn't mentioned in the info node about EREs (which, as that node treats
GNU sed EREs, probably needn't be).  would it be worth mentioning it
here?
----
     ‘^’ acts as a special character only at the beginning of the
     regular expression or subexpression (that is, after ‘\(’ or ‘\|’).
     Portable scripts should avoid ‘^’ at the beginning of a
     subexpression, though, as POSIX allows implementations that treat
     ‘^’ as an ordinary character in that context.  (Note that POSIX
     *extended* regular expressions, as well as those of GNU sed, do
     allow '^' at the beginning of a subexpression.)
----

cheers.

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