let s:tmux_option = '@vim'.substitute($TMUX_PANE, '%', '\\%', 'g')

function! tmux#inSession() abort
  return $TMUX !=# ''
endfunction

function! tmux#setNavigationFlag() abort
  call system('tmux set-window-option '.s:tmux_option.' 1')
endfunction

function! tmux#unsetNavigationFlag() abort
  call system('tmux set-window-option -u '.s:tmux_option)
endfunction

function! tmux#isSetClipboardOn() abort
  if !tmux#inSession()
    return 0
  endif
  let l:set_clipboard = trim(system('tmux show-options -g set-clipboard'))
  return l:set_clipboard ==# 'set-clipboard on'
endfunction