Vim 自动补全神器:YouCompleteMe

jopen 8年前

原文: http://blog.marchtea.com/archives/161 作者: MARCHTEA


第一次听说这个插件还是在偶然的情况下看到别人的博客,听说了这个插件的大名。本来打算在实训期间来完成安装的,无奈网实在不给力,也就拖到了回家的时候。在开始准备工作的时候就了解到这个插件不是很容易安装,安装的时候果然名不虚传。(关于这方面的内容,请查看另一篇文章)不过,有付出总有回报,安装之后用上这个插件,真心为这个插件的强大所折服。

那这个插件有何不同? 

Vim 自动补全神器:YouCompleteMe

YouCompleteMe的特别之处

基于语义补全

总所周知,Vim是一款文本编辑器。也就是说,其最基础的工作就是编辑文本,而不管该文本的内容是什么。在Vim被程序员所使用后,其慢慢的被肩负了与IDE一样的工作,文本自动补全(ie,acpomnicppcompleter),代码检查(Syntastic)等等工作。

针对文本自动补全这个功能来说,主要有两种实现方式。

基于文本

我们常用的omnicppcompleteracp,vim自带的c-x, c-n的实现方式就是基于文本。更通俗的说法,其实就是一个字:

其通过文本进行一些正则表达式的匹配,再根据生成的tags(利用ctags生成)来实现自动补全的效果。

基于语义

顾名思义,其是通过分析源文件,经过语法分析以后进行补全。由于对源文件进行分析,基于语义的补全可以做到很精确。但是这显然是vim所不可能支持的。而且经过这么多年发展,由于语法分析有很高的难度,也一直没有合适的工具出现。直到,由apple支持的clang/llvm横空出世。YouCompleteMe也正是在clang/llvm的基础上进行构建的。

整合实现了多种插件

  • clang_complete
  • AutoComplPop
  • Supertab
  • neocomplcache
  • Syntastic(类似功能,仅仅针对c/c++/obj-c代码)

支持语言

  • c
  • c++
  • obj-c
  • c#
  • python

对于其他的语言,会调用vim设置的omnifunc来匹配,因此同样支持phpruby等语言。

已知的有

使用效果图

使用感受

  • 和IDE一样,自动补全,
  • 根据include的文件进行补全
  • 不用再蹩脚的生成tags
  • 补全非常精准,而且速度很快,不会有延迟(以前在大项目上,acp用起来实在是很卡)
  • 支持类似tags的跳转,跳到定义处以及使用处
  • 出错提示很智能,并且用起来真的是如丝般柔滑,不用输入:w进行强制检测

安装

说完了那么多好处,就要说到安装了。不同于以往其他vim插件,YCM是一款编译型的插件。在下载完后,需要手动编译后才能使用。对应其他的插件来说,仅仅就是把。vim的文件丢到相应文件夹下就可以。而这也加大了使用YCM的难度。

安装准备

  • 最新版的Vim(7.3.584+),编译时添加+python标志(已经安装的可以通过vim --version查看)
  • cmake(mac可以通过homebrew安装,brew install cmake,ubuntu可以通过sudo apt-get install cmake
  • 安装vundle插件,用于安装管理vim的插件

mac下快速安装

.vimrc中添加下列代码

Bundle 'Valloric/YouCompleteMe'

保存退出后打开vim,在正常模式下输入

:BundleInstall

等待vundle将YouCompleteMe安装完成

而后进行编译安装:

cd ~/.vim/bundle/YouCompleteMe  ./install --clang-completer

如果不需要c-family的补全,可以去掉--clang-completer。如果需要c#的补全,请加上--omnisharp-completer

正常来说,YCM会去下载clang的包,如果已经有,也可以用系统--system-libclang

就这样,安装结束。打开vim,如果没有提示YCM未编译,则说明安装已经成功了。

手动编译安装

安装的脚本并不是什么时候都好用,至少对我来说是这样的。安装完之后出现了问题,参考issue#809

在用:BundleInstall安装完成或者使用

git clone --recursive https://github.com/Valloric/YouCompleteMe.git

获取最新的仓库,而后使用git submodule update --init --recursive确认仓库的完整性后,开始安装流程。

  1. 下载最新的clang二进制文件 YCM要求clang版本 > 3.2,一般来说都是下载最新的
  2. 安装python-dev。(ubuntu下使用sudo apt-get install python-dev,mac下默认提供,否则请安装command line tools
  3. 编译

    cd ~   mkdir ycm_build   cd ycm_build   cmake -G "Unix Makefiles"-DPATH_TO_LLVM_ROOT=~/ycm_temp/llvm_root_dir .~/.vim/bundle/YouCompleteMe/cpp   make ycm_support_libs

这里需要注意的是,~/ycm_temp/llvm_root_dir中包含的是根据第一步下载的压缩包解压出来的内容(包括include, bin等等文件)

这样就完成了,开始感受YCM提供的完全不逊色于大型IDE所提供的自动补全功能吧。

配置

不同于很多vim插件,YCM首先需要编译,另外还需要有配置。在vim启动后,YCM会找寻当前路径以及上层路径的.ycm_extra_conf.py。在~/.vim/bundle/YouCompleteMe/cpp/ycm/.ycm_extra_conf.py中提供了默认的模板。也可以参考我的(就在模板上改改而已)。不过这个解决了标准库提示找不到的问题。

一般来说,我会在~目录下放一个默认的模板,而后再根据不同的项目在当前目录下再拷贝个.ycm_extra_conf.py

# This file is NOT licensed under the GPLv3, which is the license for the rest  # of YouCompleteMe.  #  # Here's the license text for this file:  #  # This is free and unencumbered software released into the public domain.  #  # Anyone is free to copy, modify, publish, use, compile, sell, or  # distribute this software, either in source code form or as a compiled  # binary, for any purpose, commercial or non-commercial, and by any  # means.  #  # In jurisdictions that recognize copyright laws, the author or authors  # of this software dedicate any and all copyright interest in the  # software to the public domain. We make this dedication for the benefit  # of the public at large and to the detriment of our heirs and  # successors. We intend this dedication to be an overt act of  # relinquishment in perpetuity of all present and future rights to this  # software under copyright law.  #  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,  # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF  # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  # IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR  # OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,  # ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR  # OTHER DEALINGS IN THE SOFTWARE.  #  # For more information, please refer to <http://unlicense.org/>    import os  import ycm_core    # These are the compilation flags that will be used in case there's no  # compilation database set (by default, one is not set).  # CHANGE THIS LIST OF FLAGS. YES, THIS IS THE DROID YOU HAVE BEEN LOOKING FOR.  flags = [  '-Wall',  '-Wextra',  #'-Werror',  #'-Wc++98-compat',  '-Wno-long-long',  '-Wno-variadic-macros',  '-fexceptions',  '-stdlib=libc++',  # THIS IS IMPORTANT! Without a "-std=<something>" flag, clang won't know which  # language to use when compiling headers. So it will guess. Badly. So C++  # headers will be compiled as C headers. You don't want that so ALWAYS specify  # a "-std=<something>".  # For a C project, you would set this to something like 'c99' instead of  # 'c++11'.  '-std=c++11',  # ...and the same thing goes for the magic -x option which specifies the  # language that the files to be compiled are written in. This is mostly  # relevant for c++ headers.  # For a C project, you would set this to 'c' instead of 'c++'.  '-x',  'c++',  '-I',  '.',  '-isystem',  '/usr/include',  '-isystem',  '/usr/local/include',  '-isystem',  '/Library/Developer/CommandLineTools/usr/include',  '-isystem',  '/Library/Developer/CommandLineTools/usr/bin/../lib/c++/v1',  ]      # Set this to the absolute path to the folder (NOT the file!) containing the  # compile_commands.json file to use that instead of 'flags'. See here for  # more details: http://clang.llvm.org/docs/JSONCompilationDatabase.html  #  # Most projects will NOT need to set this to anything; you can just change the  # 'flags' list of compilation flags. Notice that YCM itself uses that approach.  compilation_database_folder = ''    if os.path.exists( compilation_database_folder ):    database = ycm_core.CompilationDatabase( compilation_database_folder )  else:    database = None    SOURCE_EXTENSIONS = [ '.cpp', '.cxx', '.cc', '.c', '.m', '.mm' ]    def DirectoryOfThisScript():    return os.path.dirname( os.path.abspath( __file__ ) )      def MakeRelativePathsInFlagsAbsolute( flags, working_directory ):    if not working_directory:      return list( flags )    new_flags = []    make_next_absolute = False    path_flags = [ '-isystem', '-I', '-iquote', '--sysroot=' ]    for flag in flags:      new_flag = flag        if make_next_absolute:        make_next_absolute = False        if not flag.startswith( '/' ):          new_flag = os.path.join( working_directory, flag )        for path_flag in path_flags:        if flag == path_flag:          make_next_absolute = True          break          if flag.startswith( path_flag ):          path = flag[ len( path_flag ): ]          new_flag = path_flag + os.path.join( working_directory, path )          break        if new_flag:        new_flags.append( new_flag )    return new_flags      def IsHeaderFile( filename ):    extension = os.path.splitext( filename )[ 1 ]    return extension in [ '.h', '.hxx', '.hpp', '.hh' ]      def GetCompilationInfoForFile( filename ):    # The compilation_commands.json file generated by CMake does not have entries    # for header files. So we do our best by asking the db for flags for a    # corresponding source file, if any. If one exists, the flags for that file    # should be good enough.    if IsHeaderFile( filename ):      basename = os.path.splitext( filename )[ 0 ]      for extension in SOURCE_EXTENSIONS:        replacement_file = basename + extension        if os.path.exists( replacement_file ):          compilation_info = database.GetCompilationInfoForFile(            replacement_file )          if compilation_info.compiler_flags_:            return compilation_info      return None    return database.GetCompilationInfoForFile( filename )      def FlagsForFile( filename, **kwargs ):    if database:      # Bear in mind that compilation_info.compiler_flags_ does NOT return a      # python list, but a "list-like" StringVec object      compilation_info = GetCompilationInfoForFile( filename )      if not compilation_info:        return None        final_flags = MakeRelativePathsInFlagsAbsolute(        compilation_info.compiler_flags_,        compilation_info.compiler_working_dir_ )        # NOTE: This is just for YouCompleteMe; it's highly likely that your project      # does NOT need to remove the stdlib flag. DO NOT USE THIS IN YOUR      # ycm_extra_conf IF YOU'RE NOT 100% SURE YOU NEED IT.      #try:      #  final_flags.remove( '-stdlib=libc++' )      #except ValueError:      #  pass    else:      relative_to = DirectoryOfThisScript()      final_flags = MakeRelativePathsInFlagsAbsolute( flags, relative_to )      return {      'flags': final_flags,      'do_cache': True    }

YouCompleteMe提供的其他功能

YCM除了提供了基本的补全功能,自动提示错误的功能外,还提供了类似tags的功能:

  • 跳转到定义GoToDefinition
  • 跳转到声明GoToDeclaration
  • 以及两者的合体GoToDefinitionElseDeclaration

可以在.vimrc中配置相应的快捷键。

nnoremap <leader>gl :YcmCompleterGoToDeclaration<CR>  nnoremap <leader>gf :YcmCompleterGoToDefinition<CR>  nnoremap <leader>gg :YcmCompleterGoToDefinitionElseDeclaration<CR>

另外,YCM也提供了丰富的配置选项,同样在.vimrc中配置。具体请参考

let g:ycm_error_symbol ='>>'let g:ycm_warning_symbol ='>*'

同时,YCM可以打开location-list来显示警告和错误的信息:YcmDiags。个人关于ycm的配置如下:

" for ycm  let g:ycm_error_symbol = '>>'  let g:ycm_warning_symbol = '>*'  nnoremap <leader>gl :YcmCompleter GoToDeclaration<CR>  nnoremap <leader>gf :YcmCompleter GoToDefinition<CR>  nnoremap <leader>gg :YcmCompleter GoToDefinitionElseDeclaration<CR>  nmap <F4> :YcmDiags<CR>

YCM提供的跳跃功能采用了vim的jumplist,往前跳和往后跳的快捷键为Ctrl+O以及Ctrl+I

总结

YouCompleteMe是我用过的最爽的一个自动补全的插件了。之前使用acp时,遇到大文件基本上就卡死了,以至于都不怎么敢使用。由于YCM使用的时C/S结构,部分使用vim脚本编写,部分认为原生代码,使得跑起来速度飞快。

抛弃Vim自带的坑爹的补全吧,抛弃ctags吧,抛弃cscope吧,YCM才是终极补全神器

在安装过程中,我也遇到了不少的坑。一会会发一篇解决这些坑的文章。

最后祝大家码年顺利,一码平川,码到功成。

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