既に開いているバッファに移動するコマンド定義

buf_open.vim

if exists('*win_gotoid')
  function! s:buf_open_existing(bname) abort " {{{
    let bnr = bufnr(a:bname)
    if bnr == -1
      echoerr 'Buffer not found:' a:bname
      return
    endif
    let wids = win_findbuf(bnr)
    if empty(wids)
      new
      execute 'buffer' bnr
    else
      call win_gotoid(wids[0])
    endif
  endfunction " }}}
else
  function! s:buf_open_existing(bname) abort " {{{
    let bnr = bufnr(a:bname)
    if bnr == -1
      echoerr 'Buffer not found:' a:bname
      return
    endif
    let tindice = map(filter(map(range(1, tabpagenr('$')), '{"tindex": v:val, "blist": tabpagebuflist(v:val)}'), 'index(v:val.blist, bnr) != -1'), 'v:val.tindex')
    if empty(tindice)
      new
      execute 'buffer' bnr
    else
      execute 'tabnext' tindice[0]
      execute bufwinnr(bnr) 'wincmd w'
    endif
  endfunction " }}}
endif
command! -bar -nargs=1 -complete=buffer Buffer  call s:buf_open_existing(<f-args>)