VIM使用（三）

Vim自动补全神器：YouCompleteMe

Ubuntu下，先通过Ｂｕｎｄｌｅ安装插件：

Bundle 'Valloric/YouCompleteMe'
Bundle 'scrooloose/syntastic'

Bundle 'Valloric/ListToggle'

Bundle 'SirVer/ultisnips'

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.acp,omnicppcompleter)，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omnicppcompleter,acp,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：

猜

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php,ruby等语言。

已知的有 * javascript —-tern_for_vim * ruby/java —-eclim

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

编译：

等待vundle将YouCompleteMe安装完成

而后进行编译安装：

sudo apt-get install python-dev
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。

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 :YcmCompleter GoToDeclaration<CR>
nnoremap <leader>gf :YcmCompleter GoToDefinition<CR>
nnoremap <leader>gg :YcmCompleter GoToDefinitionElseDeclaration<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。

UltiSnips简介：

详细参考：http://mednoter.com/UltiSnips.html

UltiSnips 只是个引擎，需要搭配预设的代码块才能运转起来，以下是我创建的几个常用代码块。

代码块集合 honza/vim-snippets　通过Ｂｕｎｄｌｅ安装：

Bundle 'honza/vim-snippets'

如果想自己创建代码块，也参考：http://mednoter.com/UltiSnips.html的内容．

这个插件很简单，给你看我的设置好了：

NeoBundle 'SirVer/ultisnips'
let g:UltiSnipsSnippetDirectories=['UltiSnips']
let g:UltiSnipsSnippetsDir = '~/.vim/UltiSnips'
let g:UltiSnipsExpandTrigger = '<Tab>'
let g:UltiSnipsListSnippets = '<C-Tab>'
let g:UltiSnipsJumpForwardTrigger = '<Tab>'
let g:UltiSnipsJumpBackwardTrigger = '<S-Tab>'

哦，对了，我想起来一件事情。g:UltiSnipsSnippetDirectories 选项的值必须是文件夹名称（可以是多个），并且这个（些）文件夹必须存在于 runtimepath 中的某一项之下。比如说 ~/.vim 就是 runtimepath 中的一项。默认的文件夹 UltiSnips 会自动创建，如果你换了，那你必须保证这个文件夹是存在的。我看你换成了 snippets，如果你事先安装过 SnipMate，那么 snippets 才会存在，否则你得自行创建。g:UltiSnipsSnippetDirectories 选项的作用是指定 UltiSnips 的搜索路径，你找不到 snippets 的原因大概就是这样。

解释为什么错了真的很累，换个角度告诉你，如果你做对了是什么样子的：

let g:UltiSnipsSnippetsDir = '~/.vim/UltiSnips' 这个设置会确保 snippets 都在指定的文件夹内（你自己编辑的也会保存在这里，如果你用了第三方的并且还要进一步编辑，你得确保都复制到了这里）
let g:UltiSnipsSnippetDirectories = ['UltiSnips'] 这个设置会告诉 UltiSnips 去哪儿找 snippets，可以是多个地方，所以如果你用第三方的 snippets，和上一个设置不在一起的话，你得把它们的路径放这里。要注意的是，这个数组里的每一项都必须在 runtimepath 其中的一项之下，所以不确定的话，先看看 runtimepath 的值。
若上述两点都做对了，那么在任意类型文件打开的前提下输入 :UltiSnipsEdit 都会打开对应类型的 snippets，能不能用，哪些能用，一看便知。

注：代码片段的扩展引用

比如在 cpp.snippets 文件的第一行增加一句 extends c ，在打开一个cpp 文件时，会首先查找搜索路径内的所有 c.snippets 文件，所以可以很容易复用已有的代码片段文件。

导航

公告