vim函数

function! SwitchToBuf(filename)
"let fullfn = substitute(a:filename, "^\\~/", $HOME . "/", "")
" find in current tab
let bufwinnr = bufwinnr(a:filename)
if bufwinnr != -1
exec bufwinnr . "wincmd w"
return
else
" find in each tab
tabfirst
let tab = 1
while tab <= tabpagenr("$")
let bufwinnr = bufwinnr(a:filename)
if bufwinnr != -1
exec "normal " . tab . "gt"
exec bufwinnr . "wincmd w"
return
endif
tabnext
let tab = tab + 1
endwhile
" not exist, new tab
exec "tabnew " . a:filename
endif
endfunction

SwitchToBuf()函数，它在所有标签页的窗口中查找指定的文件名，如果找到这样一个窗口，就跳到此窗口中；否则，它新建一个标签页来打开vimrc文件。