Prompt:
Write me a neovim lua script that keeps a history of buffers for each window and has a command for going backwards and forwards in history.
Answer:
local history = {}
local current = 0
function AddToHistory()
local bufnr = vim.fn.bufnr()
local winid = vim.fn.win_getid()
local entry = {bufnr, winid}
table.insert(history, entry)
current = #history
end
function GoBack()
if current > 1 then
current = current - 1
local entry = history[current]
vim.fn.bufload(entry[1])
vim.fn.win_gotoid(entry[2])
end
end
function GoForward()
if current < #history then
current = current + 1
local entry = history[current]
vim.fn.bufload(entry[1])
vim.fn.win_gotoid(entry[2])
end
end
vim.cmd([[autocmd BufEnter * lua AddToHistory()]])
vim.cmd([[command! -nargs=0 Back lua GoBack()]])
vim.cmd([[command! -nargs=0 Forward lua GoForward()]])
In less than 5 seconds Bing spits out the above. A quick read of it puts me in a state of mild shock. For someone who has never written Lua and is totally unfamiliar with the Neovim related APIs, this output is incredibly useful.
The generated code contains examples of basic Lua syntax:
function Name() -- function definitions
end
if P then -- if statements
end
local name = {} -- variable definitions
#history -- length of table
table.insert(index, value) -- append to table
I'm not sure what [[]] in the vim.cmd() means so I ask Bing:
Prompt:
what is double bracket syntax in lua
Answer:
In Lua, double square brackets are used to enclose literal strings which traverse several lines.
There's further info and links to Lua docs and stack overflow as well.
It familiarizes me with some of the Neovim specific APIs that are necessary for the plugin:
vim.fn.bufnr() -- get the number (ID) of the current buffer
vim.fn.win_getid() -- get the ID of the current window
vim.fn.bufload(bufnr) -- load a buffer by its number into the current window
vim.fn.win_gotoid(winid) -- move to window by its ID
vim.cmd() -- run vim script
Note: I later changed these to the vim.api.nvim_* equivalents. When asked, Bing served them up without a hitch.
It provides me with a basic structure for the plugin:
- track the history in a table
- track the current place in history
- function for adding new buffers into history
- function for going backwards in history
- function for going forwards in history
- use autocommand to track `BufEnter` events and handle them with the add function
So does it work? No, and I'm thankful for that. I will remain employed for the foreseeable future 😅.
The vim.cmd block at the bottom of the script is essentially vim script and
not Lua.
I asked Bing if it was possible to do this in pure Lua:
Prompt:
how to create an autocommand for neovim in lua
Answer:
... You can also use
vim.api.nvim_create_autocmd()to create autocommands
The answer includes a link to the Neovim Lua docs where I can learn more about this function.
The script maintains a global history across all windows instead of a separate history for each window.
I prompt Bing a couple times to try and fix this issue but never get any output better than the original. I think this "nesting" is a bit beyond the AI's current capabilities.
The script does not delete entries past the current index when opening a new file:
history:
1. file_b
2. file_a <- current
3. file_d
action:
open file_r
expected:
1. file_b
2. file_a
3. file_r <- current
actual:
1. file_b
2. file_a
3. file_d
4. fild_r <- current
To be fair, I didn't tell Bing that I wanted this behavior and honestly, I'm not really sure how to put it into simple enough terms for a prompt anyways. I'll just implement it manually.
Even if the buffer being added is the same as the current buffer, the script adds a new entry in history.
history:
1. file_b
2. file_a <- current
3. file_d
action:
open file_a
expected:
1. file_b
2. file_a <- current
3. file_d
actual:
1. file_b
2. file_a
3. file_d
4. file_a <- current
While there's plenty of work to be done, I'm significantly more confident in my ability to complete the plugin because I have a great assistant--Bing.
A few more hours of coding across a couple days and about 30 Bing prompts later, I have the plugin in a satisfactory state.
Take a look at the code. You'll see that a lot of the generated script's DNA remains. The largest addition is another command to display the history in a popup.
Manually scanning through the Neovim Lua docs is slow. It's better to first ask Bing questions like "Using lua how can I set the position of the cursor in neovim?" and "Using lua how can I close a window in neovim?" At worst the chatbot provides something to search for in the docs and at best gives a complete answer with an explanation and sources.
While there are, of course, many issues with the way large language models have been unleashed onto the world, so far, I am grateful for them. Bing chat is an excellent tool for exploring domains outside my immediate area of expertise. It does not invalidate my years of experience; it enhances it. Without that experience, I would never have been able to take what Bing generated and turn it into what I envisioned. I wouldn't know what was good or bad about it. It does however, greatly increase the velocity at which I am able to develop.
Thanks Bing 💙.