vim 的 grep 插件`Leaderf rg`： grep 和模糊匹配的完美结合

前言

vim 有很多著名的 grep 插件，我使用过的有 ack.vim ，ag.vim 和 ctrlsf.vim ，它们应该也是目前用户最多的几个了。

1. ack.vim
   起步比较早，早期后端 grep 工具是 ack，后来也支持 ag(the_silver_searcher)，pt(the_platium_searcher)，rg(ripgrep)等工具了。它是一个比较传统的 grep 插件，不支持异步，要等到 grep 结束后才能显示结果，在大的项目中 grep 会卡好一阵子。它貌似也不再维护，我 N 久前提交的 pull request 还挂在那，它最近的代码更新在 11 个月前。
2. ag.vim
   它其实是抄袭 ack.vim ，没错，是抄袭。在早期 ack.vim 还不支持 ag 时，它的作者在 ack.vim 代码的基础上稍微改了改，支持了 ag。后来被 ack.vim 的作者给怼了，就放弃了对 ag.vim 的维护。目前功能上小于 ack.vim 。
3. ctrlsf.vim
   这是国人开发的一个插件, 后端 grep 工具支持 ack/ag/pt/rg，同时也支持异步，不过需要 Vim 8.0.1039+或者 NeoVim 才支持异步。这个插件很好用，在我开发Leaderf rg之前一直使用的是它。

Leaderf rg顾名思义，后端基于 rg，由于是LeaderF的子功能，基因上就决定它完美支持异步。同时 LeaderF 又是一个非著名的模糊查找插件，这使它可以在 grep 结果的基础上再通过模糊匹配的方式进行二次过滤，来帮助用户更快地锁定目标，这是目前上面提到的插件所不具备的。

为什么选择 rg(ripgrep)

快速 grep 工具目前有 ag, rg, pt, sift, ucg 等。
我选择 rg 有以下几点原因：

1. 速度比较快，rg 的 README 上有作者的对比，我实测也是 rg 快点。
2. Windows 上 bug 少（ bug 到目前还没发现），ag 和 pt 都遇到过 bug。
3. 作者很活跃，提的 issue 能很快得到回复。
4. rg 功能相对多些，可以从rg --help 看出来。

Leaderf rg 使用介绍

Leaderf rg的使用也比较简单，只要Leaderf[!] + rg 命令和选项（同命令行上一样）就可以了。 具体使用方法可以用:Leaderf rg -h来查看。

usage: Leaderf[!] rg [-h] [-e <PATTERN>...] [-F] [-i] [-L] [-P] [-S] [-s] [-v] [-w] [-x] [--hidden] [--no-config] [--no-ignore] [--no-ignore-global] [--no-ignore-parent] [--no-ignore-vcs] [--no-pcre2-unicode] [-E <ENCODING>] [-M <NUM>] [-m <NUM>] [--max-depth <NUM>] [--max-filesize <NUM+SUFFIX?>] [--path-separator <SEPARATOR>] [--sort <SORTBY>] [--sortr <SORTBY>] [-f <PATTERNFILE>...] [-g <GLOB>...] [--iglob <GLOB>...] [--ignore-file <PATH>...] [--type-add <TYPE_SPEC>...] [-t <TYPE>...] [-T <TYPE>...] [--current-buffer | --all-buffers] [--recall] [--append] [--reverse] [--stayOpen] [--input <INPUT> | --cword] [--top | --bottom | --left | --right | --belowright | --aboveleft | --fullScreen] [--nameOnly | --fullPath | --fuzzy | --regexMode] [--nowrap] [<PATH> [<PATH> ...]] optional arguments: -h, --help show this help message and exit specific arguments: -e <PATTERN>..., --regexp <PATTERN>... A pattern to search for. This option can be provided multiple times, where all patterns given are searched. -F, --fixed-strings Treat the pattern as a literal string instead of a regular expression. -i, --ignore-case Searches case insensitively. -L, --follow Follow symbolic links while traversing directories. -P, --pcre2 When this flag is present, rg will use the PCRE2 regex engine instead of its default regex engine. -S, --smart-case Searches case insensitively if the pattern is all lowercase, case sensitively otherwise. -s, --case-sensitive Searches case sensitively. -v, --invert-match Invert matching. Show lines that do not match the given patterns. -w, --word-regexp Only show matches surrounded by word boundaries. This is roughly equivalent to putting \b before and after all of the search patterns. -x, --line-regexp Only show matches surrounded by line boundaries. --hidden Search hidden files and directories. By default, hidden files and directories are skipped. --no-config Never read configuration files. When this flag is present, rg will not respect the RIPGREP_CONFIG_PATH environment variable. --no-ignore Don't respect ignore files (.gitignore, .ignore, etc.). This implies --no-ignore-parent and --no-ignore-vcs. --no-ignore-global Don't respect ignore files that come from 'global' sources such as git's `core.excludesFile` configuration option (which defaults to `$HOME/.config/git/ignore`). --no-ignore-parent Don't respect ignore files (.gitignore, .ignore, etc.) in parent directories. --no-ignore-vcs Don't respect version control ignore files (.gitignore, etc.). --no-pcre2-unicode When PCRE2 matching is enabled, this flag will disable Unicode mode, which is otherwise enabled by default. -E <ENCODING>, --encoding <ENCODING> Specify the text encoding that rg will use on all files searched. -M <NUM>, --max-columns <NUM> Don't print lines longer than this limit in bytes. -m <NUM>, --max-count <NUM> Limit the number of matching lines per file searched to NUM. --max-depth <NUM> Limit the depth of directory traversal to NUM levels beyond the paths given. --max-filesize <NUM+SUFFIX?> Ignore files larger than NUM in size. This does not apply to directories. --path-separator <SEPARATOR> Set the path separator to use when printing file paths. --sort <SORTBY> This flag enables sorting of results in ascending order. --sortr <SORTBY> This flag enables sorting of results in descending order. -f <PATTERNFILE>..., --file <PATTERNFILE>... Search for patterns from the given file, with one pattern per line. (This option can be provided multiple times.) -g <GLOB>..., --glob <GLOB>... Include or exclude files and directories for searching that match the given glob.(This option can be provided multiple times.) --iglob <GLOB>... Include or exclude files and directories for searching that match the given glob. Globs are matched case insensitively.(This option can be provided multiple times.) --ignore-file <PATH>... Specifies a path to one or more .gitignore format rules files. --type-add <TYPE_SPEC>... Add a new glob for a particular file type. -t <TYPE>..., --type <TYPE>... Only search files matching TYPE. Multiple type flags may be provided. -T <TYPE>..., --type-not <TYPE>... Do not search files matching TYPE. Multiple type-not flags may be provided. <PATH> A file or directory to search. Directories are searched recursively. Paths specified on the command line override glob and ignore rules. --current-buffer Searches in current buffer. --all-buffers Searches in all listed buffers. --recall Recall last search. If the result window is closed, reopen it. --append Append to the previous search results. common arguments: --reverse show results in bottom-up order --stayOpen don't quit LeaderF after accepting an entry --input <INPUT> specifies INPUT as the pattern inputted in advance --cword current word under cursor is inputted in advance --top the LeaderF window is at the top of the screen --bottom the LeaderF window is at the bottom of the screen --left the LeaderF window is at the left of the screen --right the LeaderF window is at the right of the screen --belowright the LeaderF window is at the belowright of the screen --aboveleft the LeaderF window is at the aboveleft of the screen --fullScreen the LeaderF window takes up the full screen --nameOnly LeaderF is in NameOnly mode by default --fullPath LeaderF is in FullPath mode by default --fuzzy LeaderF is in Fuzzy mode by default --regexMode LeaderF is in Regex mode by default --nowrap long lines in the LeaderF window won't wrap If [!] is given, enter normal mode directly. 

注意：如果:Leaderf后面有感叹号，会直接进入 normal 模式；如果没有感叹号，则是输入模式，此时可以输入字符来进行模糊匹配过滤。可以用 tab 键在两个模式间来回切换。

Leaderf rg基本支持 rg 所有的必要选项，用户如果对 rg 命令比较熟悉，可以在 vim 命令行内输入:Leaderf, 然后手敲 rg 命令，命令选项还可以通过 tab 来补全。 当然，更聪明的做法是定义一些快捷键。例如：

" search word under cursor, the pattern is treated as regex, and enter normal mode directly noremap <C-F> :<C-U><C-R>=printf("Leaderf! rg -e %s ", expand("<cword>"))<CR> " search word under cursor, the pattern is treated as regex, " append the result to previous search results. noremap <C-G> :<C-U><C-R>=printf("Leaderf! rg --append -e %s ", expand("<cword>"))<CR> " search word under cursor literally only in current buffer noremap <C-B> :<C-U><C-R>=printf("Leaderf! rg -F --current-buffer -e %s ", expand("<cword>"))<CR> " search word under cursor literally in all listed buffers noremap <C-D> :<C-U><C-R>=printf("Leaderf! rg -F --all-buffers -e %s ", expand("<cword>"))<CR> " search visually selected text literally, don't quit LeaderF after accepting an entry xnoremap gf :<C-U><C-R>=printf("Leaderf! rg -F --stayOpen -e %s ", leaderf#Rg#visual())<CR> " recall last search. If the result window is closed, reopen it. noremap go :<C-U>Leaderf! rg --recall<CR> " search word under cursor in *.h and *.cpp files. noremap <Leader>a :<C-U><C-R>=printf("Leaderf! rg -e %s -g *.h -g *.cpp", expand("<cword>"))<CR> " the same as above noremap <Leader>a :<C-U><C-R>=printf("Leaderf! rg -e %s -g *.{h,cpp}", expand("<cword>"))<CR> " search word under cursor in cpp and java files. noremap <Leader>b :<C-U><C-R>=printf("Leaderf! rg -e %s -t cpp -t java", expand("<cword>"))<CR> " search word under cursor in cpp files, exclude the *.hpp files noremap <Leader>c :<C-U><C-R>=printf("Leaderf! rg -e %s -t cpp -g !*.hpp", expand("<cword>"))<CR> 

参考：rg 的glob 语法。

顺便说一下，直接在 vim 命令行敲:Leaderf rg，就会有传说中的"grep on the fly"的功能哦，同时支持 fuzzy 和 regex 两种模式。

会不会支持 ag 等其他 grep 工具

不会。
首先，ripgrep 已经足够强大，基本不存在别的工具有而 ripgrep 没有的功能。其次，ripgrep 有编译好的 Windows、Linux 和 MacOS 上的binary，可以在这些平台上很容易安装。再者，由于作者比较懒，不想再实现重复的功能。