How to customize the output style of quickfix list and location list using Lua?

Based on

:h quickfix-window-function

<filename>|<lnum> col <col>|<text>

I want to change it to something like this:

<filename>:<lnum>:<col>:<text>

How can this be achieved using Lua?

If you're looking to customize the display of entries in Neovim's quickfix or location list, you can use the quickfixtextfunc option to define a custom formatting function. The following Lua code provides a clean and flexible way to format quickfix or location list entries, showing

• file paths
• line numbers
• column numbers
• error types
• message text

in a consistent format.

function _G.qftf(info)
  local items
  local ret = {}

  if info.quickfix == 1 then
    items = vim.fn.getqflist({ id = info.id, items = 0 }).items
  else
    items = vim.fn.getloclist(info.winid, { id = info.id, items = 0 }).items
  end
  local valid_fmt = "%s:%d:%d:%s %s" -- filepath : line : col : type : text

  for i = info.start_idx, info.end_idx do
    local e = items[i]
    local fname = ""
    local str

    if e.valid == 1 then
      if e.bufnr > 0 then
        fname = vim.fn.bufname(e.bufnr)
        if fname == "" then
          fname = "[No Name]"
        else
          fname = fname:gsub("^" .. vim.env.HOME, "~")
        end
      end
      local lnum = e.lnum
      local col = e.col
      local qtype = e.type == "" and "" or " " .. e.type:sub(1, 1):upper()
      str = valid_fmt:format(fname, lnum, col, qtype, e.text)
    else
      str = e.text
    end
    table.insert(ret, str)
  end

  return ret
end

vim.o.quickfixtextfunc = "{info -> v:lua._G.qftf(info)}"

(optional) highlight/syntax

After setting _G.qftf()..., the original qf highlight may be affected

Therefore, you can consider adding qf.lua, for example:

~/.config/nvim/after/syntax/qf.lua

And add the following content to highlight the filepath and line number

-- ~/.config/nvim/after/syntax/qf.lua

local win_id = vim.api.nvim_get_current_win()
local ns_id = vim.api.nvim_create_namespace("qf_highlight_" .. win_id)

-- (optional)
if vim.g.qffiletype ~= nil then
  -- let g:qffiletype="cpp"
  vim.fn.clearmatches(win_id)
  vim.api.nvim_set_option_value('filetype', vim.g.qffiletype, { buf = buf_id })
else
  vim.fn.matchadd("Normal", [[.*]], 0, -1, { window = win_id })
end

vim.api.nvim_set_hl(ns_id, "HLFilepath", { fg = "#b38bfd" })
vim.api.nvim_set_hl(ns_id, "HLLine", { fg = "#3fb440" })
vim.api.nvim_win_set_hl_ns(win_id, ns_id)

vim.fn.matchadd("HLFilepath", [[^\s*.*\ze:\d\+:\d\+]], 10, -1, { window = win_id })
vim.fn.matchadd("HLLine", [[^\s*.*:\zs\d\+\ze:\d\+]], 10, -1, { window = win_id })