Run Ruby from a Vim buffer

gistfile1.vim

autocmd FileType ruby compiler ruby

function Run()
  let executable=b:current_compiler

  if !getbufvar("%", "&saved")
    let tmpfile = tempname()
    silent! exe "write " . tmpfile . ".rb"
  endif

  let filename=expand('%:p')

  " Create the previewwindow if doesn't exist
  if ! &previewwindow
    pedit /tmp/_vim_previewwindow
  endif
  " Change to the previewwindow
  silent! wincmd P
  " Run the file with and switch back to the previous window
  execute "%d|silent 0r!" . executable . " '" . filename . "'"
  wincmd p
endfunction

map <Leader>r :call Run()<CR>