Deferred loading on autocmd (#event[#pattern])

[junegunn]

Does not mean that I'm positive on this. I'm just posting the patch as it was trivial to implement the idea.

Plug 'SirVer/ultisnips',  { 'on': '#InsertEnter' }
Plug 'junegunn/goyo.vim', { 'on': ['Goyo', '#BufEnter#README,BUILD,CHANGELOG'] }

(See :help exists() for #event#pattern syntax)

[vheon]

Since which version is the #event#pattern syntax supported? Just asking because you don't seems to have a minimum version of vim for vim-plug and I wouldn't want you to break some users :)

[junegunn]

It has been quite some time.

vim/vim@f4cd3e8
vim/vim@a9b1e74

The code in this PR only uses exists('##EventName'). #event#pattern syntax was chosen not to introduce a new, arbitrary syntax, but it's not directly used. The code splits the string.

[vheon]

Thanks for digging that up! 😉 As usual I hope that there is a real use for this other than YCM (I know you get a lots of requests from it).

[blueyed]

This might be problematic.
I found this PR when looking for a better way to handle custom InsertEnter handling.

I am using the following:

    Plug 'Shougo/deoplete.nvim', {'on': []}
    …
    augroup vimplug_load_on_insertmode
      autocmd!
      autocmd InsertEnter * call plug#load(
            \ 'cursorcross.vim',
            \ 'delimitMate',
            \ 'deoplete.nvim',
            \ ) | call deoplete#enable()
            \ | autocmd! vimplug_load_on_insertmode
    augroup END

And here the call to deoplete#enable() adds a BufEnter autocmd that gets triggered then.
It is a bit weird, since plug#load() should be finished already, before deoplete#enable() then sets up the BufEnter autocmd?! (I have also put it into a separate function to make sure | does not cause it).

Maybe the BufEnter gets queued after the InsertEnter?!

[blueyed]

The dobufread happens for ftplugin …/.vim/plugged/jedi-vim//**, which is triggered through another handler:

    function s:my_insertenter_python()
      if &ft ==# 'python'
        call plug#load(
            \ 'deoplete-jedi',
            \ 'jedi-vim',
            \ )
        autocmd! vimplug_load_on_insertmode_python
      endif
    endfunction
    augroup vimplug_load_on_insertmode_python
      autocmd!
      autocmd InsertEnter * call s:my_insertenter_python()
    augroup END

[blueyed]

So, this explains the issue: there are two calls to plug#load in that setup.

[blueyed]

I think this would be good to have.

But for my use case I would need to be able to a) call a custom function afterwards (deoplete#enable()), and b) would like to limit it to a filetypes also (i.e. #InsertEnter, but only for python filetypes).

[blueyed]

call a custom function afterwards

That is also useful for lazy-loading Unite, so that you can customize it using call unite#custom#source(…) etc.

[junegunn]

@blueyed

call a custom function afterwards

vim-plug currently supports that via User autocmd

" Code to execute when the plugin is lazily loaded on demand
Plug 'junegunn/goyo.vim', { 'for': 'markdown' }
autocmd! User goyo.vim echom 'Goyo is now loaded!'

Have you tried it?

b) would like to limit it to a filetypes also (i.e. #InsertEnter, but only for python filetypes).

Hmm, I certainly wouldn't want to go that far. In my opinion, custom autocmd is the answer to such complex use cases.

[blueyed]

@junegunn

vim-plug currently supports that via User autocmd

Oh, I missed that, sorry. That is nice.
But I wonder if the autocommand name should not have something like a plug_loaded_ prefix?!
Otherwise it could conflict/overlap with a plugin's own custom User autocommand?!

Thanks!

[jbro]

I think this is a neat little feature, I'm currently using:

Plug 'vim-syntastic/syntastic', { 'on': [] }
"Delay syntatic load until we aren't doing anything
augroup LazySyntatic
  autocmd!
  autocmd CursorHold * :call plug#load('syntastic')
  autocmd CursorHold * :autocmd! LazySyntatic
augroup END

to delay the loading of syntastic. With deferred autoload that could be hidden away with:

Plug 'vim-syntastic/syntastic', { 'on': '#CursorHold' }

[SwenChan]

So, can plug support event now? I'm using SpaceVim which using 'dein' as their default plugin manager and I want to switch to plug , which is my favorite vim plugin manager. But I need this feature because so many plugin in SpaceVim need this.
So, anyone can help with this feature? @junegunn @blueyed