Unique Lines in Vim

" Unique Lines
" Barry Arthur, 2012 01 09

let b:unique_lines = []
function! Unique(line)
  let l = getline(a:line)
  1
  let n = search(l, 'w')
  if n != a:line
    return
  endif
  let n = search(l, 'W')
  if n == 0
    call add(b:unique_lines, a:line)
  endif
endfunction

22,$g/./call Unique(line('.'))
echo "Unique Lines = " . string(b:unique_lines)
nohl

finish

one
one
two
three
three
dour
four
dour