Do stuff to visual blocks.

op_on_visual_block.vim

function! OperateOnVisualBlock(expr)
  let save_reg = getreg('x')
  let save_reg_type = getregtype('x')
  normal! gv"xy
  let list = split(@x, '\n')
  let list = eval(printf(a:expr, 'list'))
  let @x = join(list, "\n")
  call setreg('X', '', 'b')
  normal! gv"xp
  call setreg('x', save_reg, save_reg_type)
endfun
function! MapVisualBlock(expr)
  let map = 'map(%s, ' . string(a:expr) . ')'
  call OperateOnVisualBlock(map)
endfunction
function! Add2VisualBlock(number)
  let expr = 'v:val + ' . a:number
  call MapVisualBlock(expr)
endfunction
xnoremap <leader>r :<C-U>call OperateOnVisualBlock('reverse(%s)')<CR>gv
xnoremap <leader>s :<C-U>call OperateOnVisualBlock('sort(%s)')<CR>gv
xnoremap <leader>m :<C-U>call MapVisualBlock('v:val + 1')<CR>gv
command! -nargs=+ OpVB call OperateOnVisualBlock(<q-args>)
command! -nargs=+ MapVB call MapVisualBlock(<q-args>)
command! -nargs=1 Add2VB call MapVisualBlock('v:val + <args>')