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

前言

vim有不少著名的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_platinum_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。它貌似也再也不维护，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
   它实际上是抄袭ack.vim，没错，是抄袭。在早期ack.vim还不支持ag时，它的做者在ack.vim代码的基础上稍微改了改，支持了ag。后来被ack.vim的做者给怼了，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，不过须要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以前一直使用的是它。

Leaderf rg顾名思义，后端基于rg，因为是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，这使它能够在grep结果的基础上再经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有的。

为何选择rg(ripgrep)

快速grep工具目前有ag, rg, pt, sift, ucg等。
我选择rg有如下几点缘由：

1. 速度比较快，rg的README上有做者的对比，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. 做者很活跃，提的issue能很快获得回复。
4. rg功能相对多些，能够从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（同命令行上同样）就能够了。 具体使用方法能够用: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.
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注意：若是:Leaderf后面有感叹号，会直接进入normal模式；若是没有感叹号，则是输入模式，此时能够输入字符来进行模糊匹配过滤。能够用tab键在两个模式间来回切换。

Leaderf rg基本支持rg全部的必要选项，用户若是对rg命令比较熟悉，能够在vim命令行内输入:Leaderf, 而后手敲rg命令，命令选项还能够经过tab来补全。 固然，更聪明的作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>
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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等其余grep工具

不会。
首先，ripgrep已经足够强大，基本不存在别的工具备而ripgrep没有的功能。其次，ripgrep有编译好的Windows、Linux和MacOS上的binary，能够在这些平台上很容易安装。再者，因为做者比较懒，不想再实现重复的功能。