Buffer Stacker (neovim plugin)

Buffer Stacker is a neovim plugin written in Lua that orders buffers in a cycle and supports navigating that cycle. It provides commands to switch to the next and previous buffers in the cycle, which maintains the ordering. When opening a file or picking a buffer out of order, however, that newly entered buffer is placed in the next position relative to the previously open buffer. The cycle of buffers can be printed as well as viewed using a telescope picker. For me, the most desired behavior was to be able to use the previous buffer command :bprevious to return to the buffer I had just left, as if the most recently visited buffer were placed on top of a stack. Vim and neovim, by contrast, sort open buffers according to their buffer numbers.

Buffer Stacker maintains a table of buffer numbers mapped to their nodes in this cycle. It also keeps a reference to the currently open buffer number. Together, the hash map and reference form a stack represented by a circular linked list. (See lua/buffer-stacker/init.lua) For example, they might look like this:

links = {
    1 = { next = 18, prev = 4 },
    4 = { next = 1, prev = 18 },
    18 = { next = 4, prev = 1 }
}
current_bufnr = 1

When navigating the cycle of buffers, the next bufnr is accessed via links[current_bufnr].next (likewise for previous), current_bufnr is updated, and a flag variable local to the plugin is set in order to prevent the reordering of the cycle. The neovim api provides functions for getting information about a buffer from its bufnr as well as entering a buffer.

Two autocommands handle updating the stack cycle (see plugin/buffer-stacker.lua). One, triggered by the BufEnter event, places the now current buffer at the top of the stack. The second, triggered by the BufDelete event, removes a buffer’s number from the cycle.