vim identify window

I have a function which opens a new window containing the results of a script

function! MyFunc()
    bo new
    se buftype=nofile
    silent! exec开发者_StackOverflow "r! sh MyScript.sh "
endfunction

I'd like to identify this specific window so that I can call my function multiple times and use the same window each time rather than opening a new window.

something like

if exists(myWindow) 
    use myWindow
else
    bo new
endif

Ok I think this might work... but... tread carefully because I am no Vim expert.

When you create the window the first time you can save it in a global:

bo new
set buftype=nofile
let g:my_run_buffer = bufnr("%")

and subsequently you can check to see if that buffer exists:

if bufexists(g:my_run_buffer)
    " Go to buffer
    set swb=usetab
    exec "sbuf " . g:my_run_buffer
else
    ... create it ...
endif

Setting "swb=usetab" will mean that when sbuf switches to the buffer, it will go to whatever window/tab it is currently open in, if it is open. I don't like setting swb globally like that, just for one sbuf call. Anyone know a better way?