在 perl 单行代码中转义和捕获的正确语法是什么？
What's the correct syntax for escapes and captures in a perl one-liner?
我正在尝试使用 pandoc 将乳胶文件（由 doxygen 自动生成）转换为 .docx 格式。我遇到了一个错误，可能是在 doxygen 中，它允许应该转义的 一些 字符（_ 和 %）在 DoxyCode 乳胶环境。一些下划线出现在文件名中，并且在大括号内。那些不应该逃脱。
我写了一个 perl 单行代码来定位任何 不在 之间的下划线或百分号，并将它们替换为反斜杠后跟相同的字符：
perl -i -pe 's/(?<!\)([_%])(?![^{]+})/\/g' test.tex
这按预期工作。但是，然后我发现某些文件在 DoxyCode 环境中包含例如大括号内的初始化列表，以及一些包含下划线的变量。所以我需要一个 perl 脚本，它可以识别下划线或百分比何时在 \begin{DoxyCode} 和 \end{DoxyCode} 之间，如果有 none.
则插入反斜杠
此命令的正则表达式有效；参见 https://regex101.com/r/gsQm2L/2
虽然它只抓取第一场比赛。我希望 perl 可以抓住其他比赛，但我可能弄错了。
我的命令是
perl -i -pe 's/(?<=begin\{DoxyCode})([\s\S]+?[^\])([_%])([\s\S]+?)(?=end\{DoxyCode})/\/g' test.tex
但它无法进行任何更改。 （我尝试不转义左大括号，但出现错误：Unescaped left brace in regex is deprecated, passed through in regex; 等）我无法判断它是找不到匹配项还是未能替换它们，因为我的捕获语法不正确。
对于第一个和第二个例子，test.tex的原始内容如下：
\begin{DoxyCode}
17 This is some code that contains an_undersc_ore and
18 an escaped\_underscore. Plus another unescaped_unders_core
19 for good measure.
20 As if that was not "bad" enough, it also contains a %percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an_underscore and
18 an escaped\_underscore. Plus another unescaped_underscore
19 for good measure.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
test.tex 的所需内容，在 运行 perl 命令之后，将是以下内容：
\begin{DoxyCode}
17 This is some code that contains an\_undersc\_ore and
18 an escaped\_underscore. Plus another unescaped\_unders\_core
19 for good measure.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an\_underscore and
18 an escaped\_underscore. Plus another unescaped\_underscore
19 for good measure.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
为什么我的 perl 单行程序失败了？我如何获得所需的输出？我绝不是 perl 或 regex 专家，所以我欢迎对其他错误的反馈。
如果相关，我正在研究 debian stretch，并且 perl --version returns
This is perl 5, version 24, subversion 1 (v5.24.1) built for x86_64-linux-gnu-thread-multi
(with 85 registered patches, see perl -V for more detail)
很简单，虽然 "right" 方法是使用正则表达式解析器，但它仍然很简单，您可以使用一个衬里来完成。关键是进行两阶段替换。我为文字反斜杠 (\) 添加了一个用例，这些反斜杠没有开始对 _ 或 % 进行转义。如果可能有其他嵌入式 {}，则可以使用相同的范例排除它们。
$text = <<'EOF';
\begin{DoxyCode}
17 This is some code that contains an_undersc_ore and
18 an escaped\_underscore. Plus another unescaped_unders_core
19 for good measure. A literal \ and a literal \_.
20 As if that was not "bad" enough, it also contains a %percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an_underscore and
18 an escaped\_underscore. Plus another unescaped_underscore
19 for good measure. A literal \%.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
EOF
print "before:\n$text\n\n";
$text =~ s{\Q\begin{DoxyCode}\E\K(.+?)(\Q\end{DoxyCode}\E)}{
my($t,$e) = (,);
$t =~ s{(\\ | \?[_%])}{1==length ? "\" : }egsx; "$t$e";
}egs;
print "after:\n$text\n";
输出：
before:
\begin{DoxyCode}
17 This is some code that contains an_undersc_ore and
18 an escaped\_underscore. Plus another unescaped_unders_core
19 for good measure. A literal \ and a literal \_.
20 As if that was not "bad" enough, it also contains a %percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an_underscore and
18 an escaped\_underscore. Plus another unescaped_underscore
19 for good measure. A literal \%.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
after:
\begin{DoxyCode}
17 This is some code that contains an\_undersc\_ore and
18 an escaped\_underscore. Plus another unescaped\_unders\_core
19 for good measure. A literal \ and a literal \\_.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an\_underscore and
18 an escaped\_underscore. Plus another unescaped\_underscore
19 for good measure. A literal \\%.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
另请阅读http://perldoc.perl.org/perlre.html and http://perldoc.perl.org/perlop.html#Regexp-Quote-Like-Operators。特别注意 \G 断言和 /gc 标志。这就是您为此任务编写合适的解析器的方式。
HTH
我正在尝试使用 pandoc 将乳胶文件（由 doxygen 自动生成）转换为 .docx 格式。我遇到了一个错误，可能是在 doxygen 中，它允许应该转义的 一些 字符（_ 和 %）在 DoxyCode 乳胶环境。一些下划线出现在文件名中，并且在大括号内。那些不应该逃脱。
我写了一个 perl 单行代码来定位任何 不在 之间的下划线或百分号，并将它们替换为反斜杠后跟相同的字符：
perl -i -pe 's/(?<!\)([_%])(?![^{]+})/\/g' test.tex
这按预期工作。但是，然后我发现某些文件在 DoxyCode 环境中包含例如大括号内的初始化列表，以及一些包含下划线的变量。所以我需要一个 perl 脚本，它可以识别下划线或百分比何时在 \begin{DoxyCode} 和 \end{DoxyCode} 之间，如果有 none.
此命令的正则表达式有效；参见 https://regex101.com/r/gsQm2L/2
虽然它只抓取第一场比赛。我希望 perl 可以抓住其他比赛，但我可能弄错了。
我的命令是
perl -i -pe 's/(?<=begin\{DoxyCode})([\s\S]+?[^\])([_%])([\s\S]+?)(?=end\{DoxyCode})/\/g' test.tex
但它无法进行任何更改。 （我尝试不转义左大括号，但出现错误：Unescaped left brace in regex is deprecated, passed through in regex; 等）我无法判断它是找不到匹配项还是未能替换它们，因为我的捕获语法不正确。
对于第一个和第二个例子，test.tex的原始内容如下：
\begin{DoxyCode}
17 This is some code that contains an_undersc_ore and
18 an escaped\_underscore. Plus another unescaped_unders_core
19 for good measure.
20 As if that was not "bad" enough, it also contains a %percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an_underscore and
18 an escaped\_underscore. Plus another unescaped_underscore
19 for good measure.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
test.tex 的所需内容，在 运行 perl 命令之后，将是以下内容：
\begin{DoxyCode}
17 This is some code that contains an\_undersc\_ore and
18 an escaped\_underscore. Plus another unescaped\_unders\_core
19 for good measure.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an\_underscore and
18 an escaped\_underscore. Plus another unescaped\_underscore
19 for good measure.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
为什么我的 perl 单行程序失败了？我如何获得所需的输出？我绝不是 perl 或 regex 专家，所以我欢迎对其他错误的反馈。
如果相关，我正在研究 debian stretch，并且 perl --version returns
This is perl 5, version 24, subversion 1 (v5.24.1) built for x86_64-linux-gnu-thread-multi
(with 85 registered patches, see perl -V for more detail)
很简单，虽然 "right" 方法是使用正则表达式解析器，但它仍然很简单，您可以使用一个衬里来完成。关键是进行两阶段替换。我为文字反斜杠 (\) 添加了一个用例，这些反斜杠没有开始对 _ 或 % 进行转义。如果可能有其他嵌入式 {}，则可以使用相同的范例排除它们。
$text = <<'EOF';
\begin{DoxyCode}
17 This is some code that contains an_undersc_ore and
18 an escaped\_underscore. Plus another unescaped_unders_core
19 for good measure. A literal \ and a literal \_.
20 As if that was not "bad" enough, it also contains a %percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an_underscore and
18 an escaped\_underscore. Plus another unescaped_underscore
19 for good measure. A literal \%.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
EOF
print "before:\n$text\n\n";
$text =~ s{\Q\begin{DoxyCode}\E\K(.+?)(\Q\end{DoxyCode}\E)}{
my($t,$e) = (,);
$t =~ s{(\\ | \?[_%])}{1==length ? "\" : }egsx; "$t$e";
}egs;
print "after:\n$text\n";
输出：
before:
\begin{DoxyCode}
17 This is some code that contains an_undersc_ore and
18 an escaped\_underscore. Plus another unescaped_unders_core
19 for good measure. A literal \ and a literal \_.
20 As if that was not "bad" enough, it also contains a %percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an_underscore and
18 an escaped\_underscore. Plus another unescaped_underscore
19 for good measure. A literal \%.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
after:
\begin{DoxyCode}
17 This is some code that contains an\_undersc\_ore and
18 an escaped\_underscore. Plus another unescaped\_unders\_core
19 for good measure. A literal \ and a literal \\_.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is unescaped.
\end{DoxyCode}
Here is some other stuff that may contain \index{things_not_to_be_escaped}.
\begin{DoxyCode}
17 This is some code that contains an\_underscore and
18 an escaped\_underscore. Plus another unescaped\_underscore
19 for good measure. A literal \\%.
20 As if that was not "bad" enough, it also contains a \%percent sign
21 that is escaped.
\end{DoxyCode}
另请阅读http://perldoc.perl.org/perlre.html and http://perldoc.perl.org/perlop.html#Regexp-Quote-Like-Operators。特别注意 \G 断言和 /gc 标志。这就是您为此任务编写合适的解析器的方式。
HTH