Creating a hidden buffer

Question

I know that with commands like sbuffer you can create a new buffer and display it in a split window, and commands like enew can create a new buffer in the current window. But is it possible to not display the buffer in any way but just create a hidden buffer right away?

My use case is that I have a python class that should return a vim.buffer object to be processed. The display happens differently depending on conditions in the calling object. So I need a buffer that I can load, and write stuff into (it's a buffer not associated with any file, so it's a nofile buftype), but that is not displayed until I command to load into the current or some other window.

Answer 1

I'm not aware that you can create a hidden unnamed buffer.

But you can create a hidden (even unlisted) buffer with some fancy name and use that.

In VimScript:

let g:myscratch = bufnr("my-fancy-name", 1)
call setbufvar(g:myscratch, "&buftype", "nofile")

The first line returns the buffer number for the buffer named "my-fancy-name". If the buffer does not exist, it is created as hidden, unlisted buffer. So you don't see it with :ls.

The second line sets the buffer as nofile.

The buffer is created, but (for whatever reasons) you cannot write to it. You first have to activate it for a moment: ^{[I didn't find another way to make it "writable".]}

let curbuf = bufnr("")
execute g:myscratch . "buffer"
execute curbuf . "buffer"

If you do this short switch of buffers in a function, you won't see it (screen is not updated).

After that you can write to it with setbufline(g:myscratch, ...) and appendbufline(g:myscratch, ...).

To bring it to view:

execute g:myscratch . "buffer"

To finally delete it use bwipeout:

execute g:myscratch . "bwipeout"