Ask the asynchronous features for Vim 8.1/8.2

[jiangjianshan]

Hello,

NERDTree is very good plugin for Vim but it seems doesn't support asynchronous features for vim 8.1/8.2. Because if we open a folder which has a huge of files inside, it will be spend many time to load it and Vim has to wait for it. The other plugin defx.nvim has been used the Remote plugin from NeoVim. It should be good idea for NERDTree can implement the asynchronous features for Vim 8.1/8.2.

[noscript]

Asynchronous vim features are only applicable when communicating with external processes.

NERDTree is implemented in pure VimScript, so async support would require to rewrite at least some parts of the plugin in another language.

[jiangjianshan]

@noscript , thanks for you reply. I'm not familar with Vim script but can read to understand them. Python is one of my familar language. Does the member has the road map to do this asynchronous feature? NERDTree is really a excellent vim plugin but only may missing the asynchronous feature.

[raven42]

would it be possible to use timer_start() along with a lambda callback to run in the background? Something like this maybe....

function! s:NERDTree.__update(name)
    ... process a:name to generate tree hierarchy
endfunction

function! s:NERDTree.update(name)
    if has('lambda') && has('timers')
        call timer_start(0, { -> s:NERDTree.__update(a:name)})
    else
        call s:NERDTree.__update(a:name)
    endif
endfunction

[noscript]

Vim is single threaded and so timers are executed in the same thread. Any long operation will freeze Vim.

[PhilRunninger]

Given that vim (and even neovim) is single-threaded, there is no sense in attempting this. Plus, I have no plans to rewrite NERDTree in another language. The reason NERDTree is so slow (and a memory hog) is that it creates an object in memory for each item on the tree. This is a very slow and memory intensive process when the tree is large, and is a lot of overhead because many of those objects are just taking up space when the files they represent aren't accessed.

There are plenty of other plugins out that either do less in terms of memory with the files, or are written at least partially as external programs. They operate better than anything I'd have the time or patience to rewrite NERDTree into.

And there are people who want Vimscript-only plugins (I was one once.), and I think NERDTree fits that bill well.