autocomplete.match.pair.vim

inoremap ( <c-r>=OpenPair('(')<CR>
inoremap ) <c-r>=ClosePair(')')<CR>
inoremap { <c-r>=OpenPair('{')<CR>
inoremap } <c-r>=ClosePair('}')<CR>
inoremap [ <c-r>=OpenPair('[')<CR>
inoremap ] <c-r>=ClosePair(']')<CR>
" just for xml document, but need not for now.
"inoremap < <c-r>=OpenPair('<')<CR>
"inoremap > <c-r>=ClosePair('>')<CR>
function! OpenPair(char)
    let PAIRs = {
                \ '{' : '}',
                \ '[' : ']',
                \ '(' : ')',
                \ '<' : '>'
                \}
    if line('$')>2000
        let line = getline('.')

        let txt = strpart(line, col('.')-1)
    else
        let lines = getline(1,line('$'))
        let line=""
        for str in lines
            let line = line . str . "\n"
        endfor

        let blines = getline(line('.')-1, line("$"))
        let txt = strpart(getline("."), col('.')-1)
        for str in blines
            let txt = txt . str . "\n"
        endfor
    endif
    let oL = len(split(line, a:char, 1))-1
    let cL = len(split(line, PAIRs[a:char], 1))-1

    let ol = len(split(txt, a:char, 1))-1
    let cl = len(split(txt, PAIRs[a:char], 1))-1

    if oL>=cL || (oL<cL && ol>=cl)
        return a:char . PAIRs[a:char] . "\<Left>"
    else
        return a:char
    endif
endfunction
function! ClosePair(char)
    if getline('.')[col('.')-1] == a:char
        return "\<Right>"
    else
        return a:char
    endif
endf

inoremap ' <c-r>=CompleteQuote("'")<CR>
inoremap " <c-r>=CompleteQuote('"')<CR>
function! CompleteQuote(quote)
    let ql = len(split(getline('.'), a:quote, 1))-1
    let slen = len(split(strpart(getline("."), 0, col(".")-1), a:quote, 1))-1
    let elen = len(split(strpart(getline("."), col(".")-1), a:quote, 1))-1
    let isBefreQuote = getline('.')[col('.') - 1] == a:quote

    if '"'==a:quote && "vim"==&ft && 0==match(strpart(getline('.'), 0, col('.')-1), "^[\t ]*$")
        " for vim comment.
        return a:quote
    elseif "'"==a:quote && 0==match(getline('.')[col('.')-2], "[a-zA-Z0-9]")
        " for Name's Blog.
        return a:quote
    elseif (ql%2)==1
        " a:quote length is odd.
        return a:quote
    elseif ((slen%2)==1 && (elen%2)==1 && !isBefreQuote) || ((slen%2)==0 && (elen%2)==0)
        return a:quote . a:quote . "\<Left>"
    elseif isBefreQuote
        return "\<Right>"
    else
        return a:quote . a:quote . "\<Left>"
    endif
endfunction

2000 行之内的文档，使用全文括号智能匹配；
大于 2000 行的文档，使用行内括号智能匹配。
这个值请自行根据计算机硬件性能调整。

http://hotoo.github.com/blog/vim-autocomplete-pairs.html

"123456"

光标在6后面的时候再次插入"，会新插入"，变成了"123456""，感觉 在此情况下应该还是"123456"