Cannot use the return value of a user-defined function defined in a user-defined plugin.

[ubaldot]

Say that I called my plugin foo with the following files:

~/.vim/packages/foo/plugin/foo.vim 
~/.vim/packages/foo/lib/myfunctions.vim 

Then, inside ./lib/myfunctions.vim, I have

vim9script

export def MyFunc(): string
    return "Hello world!"
enddef

whereas in foo.vim, I have both a mapping and a command defined:

vim9script

import autoload "../lib/myfunctions.vim"

noremap <unique> <script> <Plug>MyFunc :call <SID>myfunctions.MyFunc()<cr>

if !hasmapto("<Plug>MyFunc" ) || empty(mapcheck("<F12>", "n"))
    nnoremap <silent> <unique> <F12> <Plug>MyFunc
endif

if !exists(":FooMyFunc")
  command FooMyFunc :call <SID>myfunctions.MyFunc()
endif

Both the mapping and the command work well, and I am satisfied.

The next step I wish to perform is to use the return value of myfunction.MyFunc() in vim-airline, but I am failing.

What I have tried to do is to add the following to my .vimrc

import autoload "~/.vim/packages/foo/lib/myfunctions.vim"
augroup FOO
    autocmd!
    autocmd VimEnter * :call myfunctions.MyFunc()
augroup END
call airline#parts#define_function('foo', 'myfunctions.MyFunc')

(I used the VimEnter event to trigger the autoload mechanism)

but I get the error E121: Undefined variable: myfunctions.

[chrisbra]

honestly, I haven't tried, whether this works with vim9 script

[ubaldot]

Hum ok.
Do you have time to give it a go or what do you suggest me to do? :)