How can I reuse the same Vim window/buffer for command output, like the :help window?

Question

Though I'm no Vim expert, I've been scratching an itch by working on a rough Vim equivalent of TextMate's ⌘R functionality to run Ruby code from a buffer and display the output.

The script currently just opens a new window (split) with :new and puts the output there. If you run it multiple times, it opens multiple windows. Ideally, I'd like it to reuse the same window within each tab page, much like :help does.

I've looked but haven't found a way to achieve this. Any pointers?

Answer 1

You can create a scratch buffer with a name, so that on subsequent calls you can check to see if that buffer is already open (and if so reuse it) or you need a new one. Something like this:

function! Output()
    let winnr = bufwinnr('^_output$')
    if ( winnr >= 0 )
        execute winnr . 'wincmd w'
        execute 'normal ggdG'
    else
        new _output
        setlocal buftype=nofile bufhidden=wipe nobuflisted noswapfile nowrap
    endif
    silent! r! ls
endfunction