" -- tab switching --
nmap <M-PageUp>   gT
xmap <M-PageUp>   gT
imap <M-PageUp>   <C-O>gT
nmap <S-Tab> gT
xmap <S-Tab> gT
nmap <M-PageDown> gt
xmap <M-PageDown> gt
imap <M-PageDown> <C-O>gt

nmap <Esc>1 1gt
nmap <Esc>2 2gt
nmap <Esc>3 3gt
nmap <Esc>4 4gt
nmap <Esc>5 5gt
nmap <Esc>6 6gt
nmap <Esc>7 7gt
nmap <Esc>8 8gt
nmap <Esc>9 9gt
nmap <Esc>0 10gt
nmap <silent> <M-Home> :tabfirst<CR>
xmap <silent> <M-Home> :<C-U>tabfirst<CR>
imap <silent> <M-Home> <C-O>:tabfirst<CR>
nmap <silent> <M-End> :tablast<CR>
xmap <silent> <M-End> :<C-U>tablast<CR>
imap <silent> <M-End> <C-O>:tablast<CR>

" Original literal behaviour (improved by JumpBetweenTabs())
noremap g<S-Tab> g<Tab>
xnoremap g<S-Tab> g<Tab>
" Open the next/previous buffer in a new tab
nmap <silent> <M-S-PageDown>    :tab sbnext<CR>
nmap <silent> <M-S-PageUp>      :tab sbprevious<CR>

if exists('*function')
  " can't use <expr> because that can't handle a count
  " have to use the <C-U> to avoid passing the count to :call
  nmap <silent> g<Tab> :<C-U>call JumpBetweenTabs(v:count)<CR>
  xmap <silent> g<Tab> :<C-U>call JumpBetweenTabs(v:count)<CR>

  let g:previous_tab = 1
  " When no count is supplied, switch to the previous tab where this function
  " was called.  When a count is supplied, act like "gt".
  " (Note that "gt" effectively forgets the current tab, so afterwards, this
  " function without a count will go back to the previous-previous tab.)
  function! JumpBetweenTabs(count)
    if a:count > 0
      let g:previous_tab = tabpagenr()
      exe ":tabn" a:count
    else
      " have to figure things out first, because :exe must happen last
      let l:new_tab = g:previous_tab
      let g:previous_tab = tabpagenr()
      exe ":tabn" l:new_tab
    endif
  endfunction
endif