From 46ccd1dae562baa70c16d13e5131e651d3bb5f21 Mon Sep 17 00:00:00 2001 From: "Eric S. Raymond" Date: Tue, 28 Aug 2001 12:50:03 +0000 Subject: Plant a mention in the description of backreferences of the fact that while \0 doesn't do what one might expect, \g<0> does. --- Doc/lib/libre.tex | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/Doc/lib/libre.tex b/Doc/lib/libre.tex index aa18814..8531732 100644 --- a/Doc/lib/libre.tex +++ b/Doc/lib/libre.tex @@ -297,6 +297,8 @@ the space after the group). This special sequence can only be used to match one of the first 99 groups. If the first digit of \var{number} is 0, or \var{number} is 3 octal digits long, it will not be interpreted as a group match, but as the character with octal value \var{number}. +(There is a group 0, which is the entire matched pattern, but it can't +be referenced with \regexp{\e 0}; instead, use \regexp{\e g<0>}.) Inside the \character{[} and \character{]} of a character class, all numeric escapes are treated as characters. @@ -566,7 +568,9 @@ ignored. \samp{\e g<2>} is therefore equivalent to \samp{\e 2}, but isn't ambiguous in a replacement such as \samp{\e g<2>0}. \samp{\e 20} would be interpreted as a reference to group 20, not a reference to - group 2 followed by the literal character \character{0}. + group 2 followed by the literal character \character{0}. The + backreference \samp{\e g<0>} substitutes in the entire substring + matched by the RE. \end{funcdesc} \begin{funcdesc}{subn}{pattern, repl, string\optional{, count}} -- cgit v0.12