From: Guido van Rossum <guido@python.org>
Date: Fri, 14 Mar 1997 04:10:13 +0000 (+0000)
Subject: Hint about [\] trick to avoid quad backslashes.
X-Git-Tag: v1.5a1~290
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=1f8cee2521e8a659bf7dc02ace280dd025500409;p=python

Hint about [\] trick to avoid quad backslashes.
---

diff --git a/Doc/lib/libregex.tex b/Doc/lib/libregex.tex
index 9766c2cb30..d3f44ba862 100644
--- a/Doc/lib/libregex.tex
+++ b/Doc/lib/libregex.tex
@@ -22,9 +22,10 @@ is because Python doesn't remove backslashes from string literals if
 they are followed by an unrecognized escape character.
 \emph{However}, if you want to include a literal \dfn{backslash} in a
 regular expression represented as a string literal, you have to
-\emph{quadruple} it.  E.g.\  to extract \LaTeX\ \samp{\e section\{{\rm
+\emph{quadruple} it or enclose it in a singleton character class.
+E.g.\  to extract \LaTeX\ \samp{\e section\{{\rm
 \ldots}\}} headers from a document, you can use this pattern:
-\code{'\e \e \e \e section\{\e (.*\e )\}'}.  \emph{Another exception:}
+\code{'[\e ] section\{\e (.*\e )\}'}.  \emph{Another exception:}
 the escape sequece \samp{\e b} is significant in string literals
 (where it means the ASCII bell character) as well as in Emacs regular
 expressions (where it stands for a word boundary), so in order to
diff --git a/Doc/libregex.tex b/Doc/libregex.tex
index 9766c2cb30..d3f44ba862 100644
--- a/Doc/libregex.tex
+++ b/Doc/libregex.tex
@@ -22,9 +22,10 @@ is because Python doesn't remove backslashes from string literals if
 they are followed by an unrecognized escape character.
 \emph{However}, if you want to include a literal \dfn{backslash} in a
 regular expression represented as a string literal, you have to
-\emph{quadruple} it.  E.g.\  to extract \LaTeX\ \samp{\e section\{{\rm
+\emph{quadruple} it or enclose it in a singleton character class.
+E.g.\  to extract \LaTeX\ \samp{\e section\{{\rm
 \ldots}\}} headers from a document, you can use this pattern:
-\code{'\e \e \e \e section\{\e (.*\e )\}'}.  \emph{Another exception:}
+\code{'[\e ] section\{\e (.*\e )\}'}.  \emph{Another exception:}
 the escape sequece \samp{\e b} is significant in string literals
 (where it means the ASCII bell character) as well as in Emacs regular
 expressions (where it stands for a word boundary), so in order to