initial commit for native-only neovim plugin configuration

lua/config/autocommands.lua

@@ -1,5 +1,6 @@
 --[[
 
+
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@@ -25,30 +26,33 @@
             |  _/ /_____\__ \ || (_| | (__|   <
             |_|/___|    |___/\__\__,_|\___|_|\_\
 
-                Neovim 0.12 configuration
-                  (c) Frank Zechert 2026
+                Neovim v0.12 configuration
+                  (C) Frank Zechert 2026
 ]]
+
 local create_group = vim.api.nvim_create_augroup
 local create_cmd = vim.api.nvim_create_autocmd
-local function contains(tbl, value)
-	for _, v in ipairs(tbl) do
-		if v == value then
-			return true
-		end
-	end
-	return false
-end
 
--- briefly highlithg text that is yanked
+-- briefly highlight text that is yanked
 create_cmd("TextYankPost", {
 	desc = "Highlight yanked text",
 	group = create_group("cmd-highlight-yank", { clear = true }),
 	callback = function()
 		vim.highlight.on_yank()
-	end,
+	end
 })
 
--- recognize all scripts with bash shebang as bash filetype
+-- disable list chars in specific file types, e.g. netrw
+create_cmd("FileType", {
+	desc = "Disable list characters for some filetypes",
+	group = create_group("cmd-disable-listchars", { clear = true }),
+	pattern = { "netrw" },
+	callback = function(args)
+		vim.opt_local.list = false
+	end
+})
+
+-- when recognizing a bash shebang, switch filetype to bash
 create_cmd({"BufRead", "BufNewFile"}, {
 	desc = "Recognize bash shebang as bash filetype",
 	group = create_group("cmd-recognize-bash-filetype", { clear = true }),
@@ -59,38 +63,53 @@ create_cmd({"BufRead", "BufNewFile"}, {
 		if first_line:match("^#!.*/bash") then
 			vim.bo[buf].filetype = "bash"
 		end
-	end,
+	end
 })
 
--- disable list chars in specific filetypes, e.g. netrw
-create_cmd({"FileType"}, {
-	desc = "Disable list chars for some filetypes",
-	pattern = { "netrw" },
-	callback = function(args)
-		vim.opt_local.list = false
-	end,
-})
-
--- automatically remove trailing whitespace on save file
-create_cmd({"BufWritePre"}, {
-	desc = "Remove trailing whitespace when saving",
+-- when saving a file, remove trailing whitespace
+create_cmd("BufWritePre", {
+	desc = "Remove trailing whitespace before saving a file",
 	group = create_group("cmd-remove-trailing-whitespace", { clear = true }),
 	pattern = "*",
 	callback = function(args)
 		vim.api.nvim_buf_call(args.buf, function()
-			vim.cmd([[%s/\s\+$//e]])
+			local cursor = vim.api.nvim_win_get_cursor(0)
+			vim.cmd([[keepjumps keeppatterns silent! %s/\s\+$//e]])
+			vim.api.nvim_win_set_cursor(0, cursor)
 		end)
-	end,
+	end
 })
 
--- automatically set textwidth if not set otherwise
-create_cmd({"FileType"}, {
-	desc = "Automatically set textwidth",
-	pattern = "*",
-	callback = function(args)
-		local buf = args.buf
-		if vim.bo[buf].textwidth == 0 then
-			vim.bo[buf].textwidth = vim.g.ui.textwidth[vim.bo[buf].filetype] or vim.g.ui.textwidth.default
+
+-- highlight trailing whitespace when in normal mode
+local trailing_hl_group = create_group("cmd-highlight-trailing-whitespace", { clear = true })
+local trailing_hl_match_ids = {}
+-- Remove highlight in all non-normal modes
+create_cmd({"InsertEnter", "CmdlineEnter", "TermEnter" }, {
+	desc = "Remove trailing whitespace highlight in non-normal mode",
+	group = trailing_hl_group,
+	callback = function()
+		local window = vim.api.nvim_get_current_win()
+		local id = trailing_hl_match_ids[window]
+		if id then
+			pcall(vim.fn.matchdelete, id)
+			trailing_hl_match_ids[window] = nil
 		end
-	end,
+	end
+})
+-- Apply highlight in normal mode
+create_cmd({"InsertLeave", "CmdlineLeave", "TermLeave", "BufEnter", "WinEnter" }, {
+	desc = "Add trailing whitespace highlight in normal mode",
+	group = trailing_hl_group,
+	callback = function()
+		if vim.fn.mode() ~= "n" then
+			return
+		end
+		local window = vim.api.nvim_get_current_win()
+		local id = trailing_hl_match_ids[window]
+		if id then
+			pcall(vim.fn.matchdelete, id)
+		end
+		trailing_hl_match_ids[window] = vim.fn.matchadd("TrailingWhitespace", [[\s\+$]])
+	end
 })