Question

While has("menu") can tell me if gvim will support the menu command, is there a way to test in vim script if any menu currently exists?

The closest thing that I could figure out is to execute the :menu command and count the output. For example, in rough pseudo code…

  if count(":menu") != '0'
     " something has created a menu and is visible on screen
  else
     " no menus have been created
  endif

Answer 1

Your request is unusual; that’s why menu items probably aren’t covered by exists() or a function analog to maparg().

You have to do this as outlined in your pseudo code:

redir => menuOutput
silent! menu
redir END

if menuOutput =~# '--- Menus ---\n$'
    " no menus
endif

---

^{PS: Overreliance on menus is a Vim “smell”; for one, you don’t have them (easily accessible) when using console Vim.}