用Youcompleteme打造VIM的IDE

一直习惯在Linux用VIM看代码，但VIM相比VisualStudio和SourceInsight易用性差很多

最需要给VIM添加的功能是

1） 代码跳转，浏览变量函数定义实现等

2）代码自动补全

网上找了一圈发现了这个大神级的插件YouCompleteMe,是Google的工程师Val Markovic开发的，项目地址https://github.com/Valloric/YouCompleteMe

安装Vundle和YouCompleteMe

首先安装VIM的插件管理器，https://github.com/VundleVim/Vundle.vim

mkdir ~/.vim/bundle/

cd ~/.vim/bundle

git clone https://github.com/VundleVim/Vundle.vim.git

编辑~/.vimrc，添加YouCompleteMe的地址

set nocompatible " be iMproved, requiredfiletype off " required" set the runtime path to include Vundle and initializeset rtp+=~/.vim/bundle/Vundle.vimcall vundle#begin()" alternatively, pass a path where Vundle should install plugins"call vundle#begin('~/some/path/here')" let Vundle manage Vundle, requiredPlugin 'VundleVim/Vundle.vim'" The following are examples of different formats supported." Keep Plugin commands between vundle#begin/end." plugin on GitHub repoPlugin 'Valloric/YouCompleteMe'"Plugin 'scrooloose/nerdtree'"Plugin 'jistr/vim-nerdtree-tabs'" plugin from http://vim-scripts.org/vim/scripts.htmlPlugin 'taglist.vim'" Git plugin not hosted on GitHub"Plugin 'git://git.wincent.com/command-t.git'" git repos on your local machine (i.e. when working on your own plugin)"Plugin 'file:///home/gmarik/path/to/plugin'" The sparkup vim script is in a subdirectory of this repo called vim." Pass the path to set the runtimepath properly."Plugin 'rstacruz/sparkup', {'rtp': 'vim/'}" Install L9 and avoid a Naming conflict if you've already installed a" different version somewhere else." Plugin 'ascenator/L9', {'name': 'newL9'}" All of your Plugins must be added before the following linecall vundle#end() " requiredfiletype plugin indent on " required" To ignore plugin indent changes, instead use:"filetype plugin on"" Brief help" :PluginList - lists configured plugins" :PluginInstall - installs plugins; append `!` to update or just :PluginUpdate" :PluginSearch foo - searches for foo; append `!` to refresh local cache" :PluginClean - confirms removal of unused plugins; append `!` to auto-approve removal"" see :h vundle for more details or wiki for FAQ" Put your non-Plugin stuff after this line

重新启动VIM，执行:PluginInstall，即可安装完成

启动vim，发现vim版本太老，我的ubuntu还是14.04，vim版本是7.4.52

Youcompleme提示需要至少7.4.1578+的版本

因此下载了最新的vim代码，重新编译安装vim8.0,步骤请参考Building Vim From source.

编译ycmd

YouCompleteMe依赖ycmd模块实现代码补全功能，ycmd又依赖clang实现C/C++代码的解析

用YouCompleteMe自带的install.sh脚本完成ycmd的安装

sudo apt-get install build-essential cmake
sudo apt-get install python-dev python3-dev
cd ~/.vim/bundle/YouCompleteMe
./install.py --clang-completer

配置YouCompleteMe

至此用vim打开c文件，可以实现单个文件内的补全

但是无法跳转，无法跨文件补全，原因是没有正确配置clang的编译flag

将~/.vim/bundle/YouCompleteMe/third_party/ycmd/cpp/ycm/.ycm_extra_conf.py复制到代码所在的目录（或上级目录，本级目录找不到ycmd会自动往上找）

在flags数组中添加c代码需要的头文件路径，编译开关等

flags = ['-Wall','-Wextra','-Werror','-fexceptions','-DNDEBUG',# 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.../include','-I.../utils',‘-D...''-D...']

再次打开c代码文件，会有红色的地方显示clang编译出错的代码行，可以根据提示慢慢修改.ycm_extra_conf 直至没有错误，如果有些错误行不需要跳转或者补全，可以不管

最后定义跳转快捷键

map <F2> :YcmCompleter GoTo<CR>

把光标移到某个函数位置，按F2，vim自动跳到了函数定义处，哈哈！

补充

2017-6-11

YcmCompleter只能实现单个编译上下文内的跳转，所以单个编译上下文指的是一个C/C++文件以及它包含的所有头文件

所以无法跳转到定义在另一个c/c++文件中的函数，这可能是YcmComplete跳转功能的硬伤

个人认为用YcmComplete实现代码补全非常合适，但是文件跳转还需要其他更强大的工具