Configuring variable-width tab spacing in Vim

Question

I sometimes want Vim to read tab-formatted files where the most reasonable formatting implies a non-uniform tab width. In other words, I want a tab stop at positions:

5, 30, 50, 60, 70, 80

How can I do this in Vim?

Answer 1

If you don't actually need to change the tabstops and can get away with just inserting the correct number of spaces, I would suggest you script it. Here's a quick and dirty version that might do what you want:

let s:tabstops = [0, 5, 30, 50, 60, 70, 80]
fun! Find_next(pos)
  if a:pos > min(s:tabstops) && a:pos < max(s:tabstops) 
    let my_count = 0
    while my_count < len(s:tabstops) - 1
      if a:pos > get(s:tabstops, my_count) && a:pos < get(s:tabstops, my_count+1)
        return get(s:tabstops, my_count+1)
      endif
      let my_count = my_count + 1
    endwhile
    return -1
  endif
  return -1
endfun
fun! Tabbing()
  let pos = col('.')
  let next_stop = Find_next(pos)
  let the_command = "normal i"
  let my_count = 0
  while my_count < next_stop - pos
    let the_command = the_command . " "
    let my_count = my_count + 1
  endwhile
  let the_command = the_command . ""
  execute the_command
endfun
imap <TAB> j<ESC>:call Tabbing()<CR>lxi