今天要写一个逻辑结构比较明朗的文档，Emacs 的 outline mode 是很好的，但是太久不用了，实在习惯不了 Emacs 的操作方式，Vim 怎么就没有这样的模式呢？Google 了一下，找到了这个： Emacs outline mode for Vim，就在 vim.org 的网站上。把这个 outline.vim 下载下来之后放到 ~/.vim/syntax/ 下面就行了，用的时候 :set ft=outline 就激活这个模式，可以自己调整一下颜色。Outline 模式的格式很简单：
* 一级标题 ** 二级标题 *** 三级标题 **** 四级标题
依此类推。
Win32 版本的 gvim 是要放到自己的主目录下的 vimfiles\syntax\ 下面，主目录就是 USERPROFILE 这个环境变量的值，一般就是 C:\Documents and Settings\USERNAME。
这里的 ~/.vim 和 vimfiles 目录可以在 vim 里用 :set runtimepath 看到。
贴一下代码，以防原链接失效。
File: syntax/outline.vim
"
" Description:
"
" This uses folding to mimic outline-mode in Emacs. Set filetype to
" 'outline' to activate this functinality. Put it in the modeline to
" preserve outlines between edits. For example:
"
" vim:set ft=outline:
"
" Installation:
"
" Place this file in your home directory under ~/.vim/syntax/, or in the
" system location under the syntax/ directory to provide it to all users
"
" Maintainer: Tye Z.
"
" Customization:
"
" The colors of the outline headers can be changed by linking them to
" whatever you like. For example:
"
" hi! link Outline_1 Statement
"
" History:
"
" Version 1.1:
"
" - Initial version
"
"
" Highlighting for the section header lines. Add to more levels here.
"
syn match Outline_1 /^\*\{1\}[^*].*$/
syn match Outline_2 /^\*\{2\}[^*].*$/
syn match Outline_3 /^\*\{3\}[^*].*$/
syn match Outline_4 /^\*\{4\}[^*].*$/
"hi! default link Outline_1 Comment
"hi! default link Outline_2 Identifier
"hi! default link Outline_3 PreProc
"hi! default link Outline_4 Type
hi Outline_1 cterm=underline ctermfg=4 gui=bold,underline guifg=Blue
hi Outline_2 cterm=underline ctermfg=3 gui=bold,underline guifg=Brown
hi Outline_3 cterm=underline ctermfg=5 gui=bold,underline guifg=Magenta
hi Outline_4 cterm=underline ctermfg=6 gui=bold,underline guifg=SeaGreen
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
setl foldmethod=expr
setl foldexpr=OutlineFoldFunc()
function! OutlineFoldFunc()
let line = getline(v:lnum)
" If the current line starts with a '*', then this is start of a fold
if line =~ '^\*'
return ">" . matchend(line, "^\**")
else
" Since this is not the start of a fold, see if this is the END of
" one. We are at the end of a fold when the next line has nothing
" but whitespace, and the following line is the start of a fold.
" We look two lines ahead so we can display only the LAST blank
" line. If there are no blank lines, then the start of the next
" fold will automatically end this one.
let line2 = getline(v:lnum+1)
if line2 =~ '^\s*$'
let line3 = getline(v:lnum+2)
if line3 =~ '^\*'
return "<" . matchend(line3, "^\**")
endif
endif
endif
return "=" " fold-level has not changed
endfunction
它的折叠功能还不够完善，如果不喜欢，把 setl foldmethod=expr 那句注释掉就行了。