Template:Language exist/doc

Shows a flag if a translated page with the given suffix exists, otherwise shows <span></span>.

Further explanation

Input: Given language code, for example de, en for English

if on page with the given language code then

  show nothing -- nothing = <span></span>

else

  if <pagename without lang suffix>/<given lang code> exists then -- current page translated to given language
    show flag
  else
    show nothing -- nothing = <span></span>
  end

end