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 l:customtabline = ''
    let l:currenttabnum = tabpagenr()
    let l:lasttabnumber = tabpagenr('$')
    let l:tabnumber = 1
    while l:tabnumber <= l:lasttabnumber
      let l:buflist = tabpagebuflist(l:tabnumber)
      let l:winnr = tabpagewinnr(l:tabnumber)

      if l:lasttabnumber > 1
        let l:customtabline .= '%' . l:tabnumber . 'T'
        let l:customtabline .= (l:tabnumber == l:currenttabnum ? '%1*' : '%2*')

        let l:customtabline .= (l:tabnumber == l:currenttabnum ? '%#TabNumSel#' : '%#TabNum#')
        let l:customtabline .= ' ' . l:tabnumber
        let l:customtabline .= '%#TabSeparator#:'
        let l:customtabline .= (l:tabnumber == l:currenttabnum ? '%#TabLineItemSel#' : '%#TabLineItem#')
      endif

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

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

      elseif l:buftype ==# 'quickfix'
        let l:file = 'quickfix'

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

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

      endif

      if l:file ==# ''
        let l:file = "''"
      endif

      let l:customtabline .= l:file . ' %#TabLineNoise# '

      let l:tabnumber = l:tabnumber + 1

    endwhile

    let l:customtabline .= '%T%#TabLineFill#%='
    let l:customtabline .= '%#TabLineItemSel# %{fugitive#statusline()}%#TabSeparator# '
    let l:customtabline .= '%#TabLineNoise# '
    let l:customtabline .= '%#TabLineNoise# '
    " let l:customtabline .= '%#TabSeparator# "%#TabLineItemSel#%{v:register}%#TabSeparator#" '
    " let l:customtabline .= '%#TabLineNoise# '
    let l:customtabline .= "%#TabLineItemSel# %{ObsessionStatus(fnamemodify(v:this_session,':t'),'---')} %*"

    return l:customtabline

  endfunction

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

endif " exists("+showtabline")