random pick name from buffer with vimScript on vim

raffle.vim

" vimScript
" -- On dailies, for random choice on given buffer with names
function! StringInLine(line_number, search_string)
  let line_text = getline(a:line_number)
  let match_position = match(line_text, a:search_string)
  return match_position >= 0
endfunction

function! Raffle()
    let total_lines = line('$')
    let random_line = (RandLine() % total_lines) + 1
    let line_text = getline(random_line)

    if StringInLine(random_line, '>> ')
        :call Raffle()
    else
        let line_text = '>> ' . line_text
        call setline(random_line, line_text)
    endif
endfunction

function! RandLine()
  return str2nr(matchstr(reltimestr(reltime()), '\v\.@<=\d+')[1:])
endfunction
" -- run it with -> :call Raffle()
"  by d4rk3r