" site: http://rayninfo.co.uk/vimtips.html
" advanced incrementing (really useful)
" put following in _vimrc
let g:I=0
function! INC(increment)
  let g:I =g:I + a:increment
  return g:I
endfunction

" eg create list starting from 223 incrementing by 5 between markers a,b
:let I=223
:'a,'bs/^/\=INC(5)/
" create a map for INC
cab viminc :let I=223 \| 'a,'bs/$/\=INC(5)/