vim/vimrc.d/tabline.vim

if exists("+showtabline")

  " Rename tabs to show tab number.
  " based on:
  " http://stackoverflow.com/questions/5927952/whats-implementation-of-vims-default-tabline-function

  function! MyTabLine()
    let s = ''
    let t = tabpagenr()
    let i = 1
    while i <= tabpagenr('$')
      let buflist = tabpagebuflist(i)
      let winnr = tabpagewinnr(i)
      let s .= '%' . i . 'T'
      let s .= (i == t ? '%1*' : '%2*')

      let s .= (i == t ? '%#TabNumSel#' : '%#TabNum#')
      let s .= ' ' . i
      let s .= '%#TabSeparator#:'
      let s .= (i == t ? '%#TabLineItemSel#' : '%#TabLineItem#')

      let bufnr = buflist[winnr - 1]
      let file = bufname(bufnr)
      let buftype = getbufvar(bufnr, '&buftype')

      if buftype == 'help'
        let file = 'help:' . fnamemodify(file, ':t:r')

      elseif buftype == 'quickfix'
        let file = 'quickfix'

      elseif buftype == 'nofile'
        if file =~ '\/.'
          let file = substitute(file, '.*\/\ze.', '', '')
        endif

      else
        let file = fnamemodify(file, ':p:t')

      endif

      if file == ''
        let file = "''"
      endif

      let s .= file . ' %#mNoise# '

      let i = i + 1

    endwhile

    let s .= '%T%#TabLineFill#%='
    let s .= '%#mNoise# '
    let s .= '%#TabSeparator# "%#TabLineItemSel#%{v:register}%#TabSeparator#" '
    let s .= '%#mNoise# '
    let s .= "%#TabLineItemSel# %{ObsessionStatus(fnamemodify(v:this_session,':t'),'---')} %*"

    return s

  endfunction

  highlight def link TabNum Comment
  highlight def link TabNumSel String
  highlight def link TabSeparator Comment
  highlight def link TabLineItem Comment
  highlight def link TabLineItemSel String

  set showtabline=2
  set tabline=%!MyTabLine()

endif " exists("+showtabline")