什么是\&Vim 正则表达式中的模式 [英] What is the \& pattern in Vim's Regex

问题描述

我最近在 Vim 正则表达式内置函数中遇到了分支说明符.\& 上的 Vim 帮助部分包含以下内容:

I recently came across the branch specifier in Vim regex builtins. Vim's help section on \& contains this:

A branch is one or more concats, separated by "\&".  It matches the last
concat, but only if all the preceding concats also match at the same
position.  Examples:
      "foobeep\&..." matches "foo" in "foobeep".
      ".*Peter\&.*Bob" matches in a line containing both "Peter" and "Bob"

目前尚不清楚它是如何使用的以及用于什么目的.很好地解释它的作用和使用方式会很棒.

It's not clear how it is used and what it is used for. A good explanation of what it does and how it is used would be great.

要清楚，这是不是在替换中使用的&(替换为完整匹配)，这是\&在模式中使用.

To be clear this is not the & (replace with whole match) used in a substitution, this is the \& used in a pattern.

示例用法:

/\c\v([^aeiou]&\a){4}

用于搜索4个连续的辅音(取自vim提示).

Used to search for 4 consecutive consonants (Taken from vim tips).

推荐答案

说明:

\& 对应于 \|，就像 and 运算符对应于 or 运算符.因此，两个 concat 必须匹配，但只有最后一个会突出显示.

\& is to \|, what the and operator is to the or operator. Thus, both concats have to match, but only the last will be highlighted.

示例 1:

(以下测试假设 :setlocal hlsearch.)

想象一下这个字符串:

foo foobar

现在，/foo 将在两个单词中突出显示 foo.但有时您只想匹配 foobar 中的 foo.那么你必须使用 /foobar\&foo.

Now, /foo will highlight foo in both words. But sometimes you just want to match the foo in foobar. Then you have to use /foobar\&foo.

反正就是这样.经常使用吗?到目前为止，我还没有看到它超过几次.在这种简单的情况下，大多数人可能会使用零宽度原子.例如.可以通过 /foo\zebar 完成与本示例相同的操作.

That's how it works anyway. Is it often used? I haven't seen it more than a few times so far. Most people will probably use zero-width atoms in such simple cases. E.g. the same as in this example could be done via /foo\zebar.

示例 2:

/\c\v([^aeiou]&\a){4}.

\c - 忽略大小写

\v - 非常神奇"(-> 在这种情况下，您不必转义 &)

\v - "very magic" (-> you don't have to escape the & in this case)

(){4} - 重复相同的模式 4 次

(){4} - repeat the same pattern 4 times

[^aeiou] - 排除这些字符

\a - 字母字符

因此，这个相当令人困惑的正则表达式将匹配 xxxx、XXXX、wXyZ 或 WxYz 但不匹配AAAA 或 xxx1.简单来说:匹配任何不包含 'a'、'e'、'i'、'o' 或 'u' 的 4 个字母字符的字符串.

Thus, this, rather confusing, regexp would match xxxx, XXXX, wXyZ or WxYz but not AAAA or xxx1. Putting it in simple terms: Match any string of 4 alphabetic characters that doesn't contain either 'a', 'e', 'i', 'o' or 'u'.

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