how to copy markdown code block?

[tfriedel]

Copilot Chat typically replies with markdown code blocks,
e.g.

```py
print("hello")
```

I find myself often copying the code from the copilot chat buffer to another buffer.
I know there's this diff tool, but sometimes I need to do it manually because I may only want to copy one block.

What's the easiest way to copy only the code?
There's probably some nice setup involving e.g. vim surround or maybe treesitter to identify the code inside the triple backticks (excluding the bit with the name of the language).

[tfriedel]

I ended up using something suggested by ChatGPT. If anyone knows something better, I'm still interested.

-- identifies code between ``` and yanks it
function YankCodeBlock()
  -- Find the start of the code block
  local start_line = vim.fn.search("^```", "bnW")
  if start_line == 0 then
    return
  end

  -- Find the end of the code block
  local end_line = vim.fn.search("^```", "nW")
  if end_line == 0 then
    return
  end

  -- Adjust start line to skip the language identifier
  start_line = start_line + 1

  -- Yank the content
  vim.cmd(string.format("%d,%dy", start_line, end_line - 1))
  print("Code block yanked")
end

-- Set the mapping
vim.api.nvim_set_keymap("n", "<leader>yc", [[:lua YankCodeBlock()<CR>:echo<CR>]], { noremap = true, silent = true })

[thenbe]

You can do this with the "fenced code block" text object, courtesty of nvim-various-textobjs.

It allows you to press yiC to copy whatever is in the fenced code block.

{
  'chrisgrieser/nvim-various-textobjs',
  lazy = false,
  config = function()
    -- https://github.com/chrisgrieser/nvim-various-textobjs#list-of-text-objects
    require('various-textobjs').setup({
      useDefaultKeymaps = false,
    })

    vim.api.nvim_create_autocmd("FileType", {
      group = vim.api.nvim_create_augroup('markdown_keymaps', { clear = true }),
      pattern = { "markdown", "copilot-chat" },
      callback = function()
        vim.keymap.set({ "o", "x" }, "aC", '<cmd>lua require("various-textobjs").mdFencedCodeBlock(false)<CR>', { desc = "Around Fenced Code Block" })
        vim.keymap.set({ "o", "x" }, "iC", '<cmd>lua require("various-textobjs").mdFencedCodeBlock(true)<CR>', { desc = "Inside Fenced Code Block" })
      end,
    })
  end,
}

[jellydn]

I don't thave this setup but using flash.nvim to quickly select the codeblock for me.

[tfriedel]

Thanks for both of the suggestions! I'm already using flash.nvim.
Together with the remote treesitter functionality I can yank the block without first moving around.
The nvim-various-textobjs solution searches forward for textobjects, so I'd first need to jump either into or before it.

To make the flash.nvim work for the copilotchat buffer, I first had to tell treesitter to treat it as markdown. So I added this to my autoload.lua:

vim.api.nvim_create_autocmd("FileType", {
  pattern = "copilot-chat",
  callback = function()
    vim.bo.filetype = "markdown"
  end,
})