Emacs - Lisp 中的正则表达式需要双重转义 - 为什么? [英] Emacs - regular expressions in Lisp need to be double-escaped - why?

问题描述

我一直在玩 emacs lisp，我想写一个小函数来进行正则表达式搜索和替换.我花了很长时间让正则表达式正常工作，因为我没有意识到在编写 lisp 代码时所有特殊字符都需要双重转义(但在交互使用 query-replace-regexp 时不需要！).

I've been playing around with emacs lisp, and I wanted to write a little function to do a regular expression search and replace. I had a heck of a time getting the regular expression to work correctly because I didn't realize that all the special characters need to be double escaped when writing lisp code (but not when using query-replace-regexp interactively!).

例如，交互地使用 query-replace-regexp 你可以使用

So for example, using query-replace-regexp interactively you can use

^(.*)[	]-.*$

但是在编写elisp代码时，您需要像这样双重转义所有内容:

but when writing elisp code you need to double escape everything like so:

^\(.*\)[	]-.*$  

我终于在 Steve Yegge 文章中找到了对此的引用，但是我想知道有没有人知道这是为什么?

I finally found a reference to this in a Steve Yegge article, but I was wondering if anyone knew why this is?

推荐答案

这是因为您需要对字符串中的反斜杠进行转义.如果不转义字符串中(的反斜杠，结果只是(

It's because you need to escape backslashes in strings. If you don't escape the backslash of ( in the string, it turns out to be just (

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