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Hint about [\] trick to avoid quad backslashes.

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Guido van Rossum 1997-03-14 04:10:13 +00:00
parent db5a41f16b
commit 1f8cee2521
2 changed files with 6 additions and 4 deletions
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5
Doc/lib/libregex.tex
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@ -22,9 +22,10 @@ is because Python doesn't remove backslashes from string literals if
they are followed by an unrecognized escape character. they are followed by an unrecognized escape character.
\emph{However}, if you want to include a literal \dfn{backslash} in a \emph{However}, if you want to include a literal \dfn{backslash} in a
regular expression represented as a string literal, you have to 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: \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 the escape sequece \samp{\e b} is significant in string literals
(where it means the ASCII bell character) as well as in Emacs regular (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 expressions (where it stands for a word boundary), so in order to

5
Doc/libregex.tex
View file

@ -22,9 +22,10 @@ is because Python doesn't remove backslashes from string literals if
they are followed by an unrecognized escape character. they are followed by an unrecognized escape character.
\emph{However}, if you want to include a literal \dfn{backslash} in a \emph{However}, if you want to include a literal \dfn{backslash} in a
regular expression represented as a string literal, you have to 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: \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 the escape sequece \samp{\e b} is significant in string literals
(where it means the ASCII bell character) as well as in Emacs regular (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 expressions (where it stands for a word boundary), so in order to