lualoader: Address some 'luacheck' concerns

luacheck pointed out an assortment of issues, ranging from non-standard
globals being created as well as unused parameters, variables, and redundant
assignments.

Using '_' as a placeholder for values unused (whether it be parameters
unused or return values unused, assuming multiple return values) feels clean
and gets the point across, so I've adopted it. It also helps flag candidates
for cleanup later in some of the lambdas I've created, giving me an easy way
to re-evaluate later if we're still not using some of these features.

stand/lua/cli.lua

@@ -50,7 +50,7 @@ local parse_boot_args = function(argv, with_kernel)
 	local kernel_name
 	local argstr = ""
 
-	for k, v in ipairs(argv) do
+	for _, v in ipairs(argv) do
 		if with_kernel and v:sub(1,1) ~= "-" then
 			kernel_name = v
 		else
@@ -92,7 +92,7 @@ end
 -- Module exports
 
 function cli.boot(...)
-	local cmd_name, argv = cli.arguments(...)
+	local _, argv = cli.arguments(...)
 	local kernel, argstr = parse_boot_args(argv)
 	if kernel ~= nil then
 		loader.perform("unload")
@@ -102,7 +102,7 @@ function cli.boot(...)
 end
 
 function cli.autoboot(...)
-	local cmd_name, argv = cli.arguments(...)
+	local _, argv = cli.arguments(...)
 	local argstr = parse_boot_args(argv, false)
 	core.autoboot(argstr)
 end
@@ -110,7 +110,7 @@ end
 -- Used for splitting cli varargs into cmd_name and the rest of argv
 function cli.arguments(...)
 	local argv = {...}
-	local cmd_name = ""
+	local cmd_name
 	cmd_name, argv = core.popFrontTable(argv)
 	return cmd_name, argv
 end

stand/lua/config.lua

@@ -37,7 +37,7 @@ local carousel_choices = {}
 pattern_table = {
 	[1] = {
 		str = "^%s*(#.*)",
-		process = function(k, v)  end
+		process = function(_, _)  end
 	},
 	--  module_load="value"
 	[2] = {
@@ -94,7 +94,7 @@ pattern_table = {
 	--  exec="command"
 	[9] = {
 		str = "^%s*exec%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
-		process = function(k, v)
+		process = function(k, _)
 			if loader.perform(k) ~= 0 then
 				print("Failed to exec '" .. k .. "'")
 			end
@@ -283,10 +283,7 @@ function config.parse(name, silent)
 		return silent
 	end
 
-	local text
-	local r
-
-	text, r = io.read(f)
+	local text, _ = io.read(f)
 
 	if text == nil then
 		if not silent then
@@ -302,7 +299,7 @@ function config.parse(name, silent)
 		if line:match("^%s*$") == nil then
 			local found = false
 
-			for i, val in ipairs(pattern_table) do
+			for _, val in ipairs(pattern_table) do
 				local k, v, c = line:match(val.str)
 				if k ~= nil then
 					found = true
@@ -339,7 +336,7 @@ function config.loadkernel(other_kernel)
 
 	local try_load = function (names)
 		for name in names:gmatch("([^;]+)%s*;?") do
-			r = loader.perform("load " .. flags .. " " .. name)
+			local r = loader.perform("load " .. flags .. " " .. name)
 			if r == 0 then
 				return name
 			end
@@ -376,7 +373,7 @@ function config.loadkernel(other_kernel)
 		-- Use our cached module_path, so we don't end up with multiple
 		-- automatically added kernel paths to our final module_path
 		local module_path = config.module_path
-		local res = nil
+		local res
 
 		if other_kernel ~= nil then
 			kernel = other_kernel
@@ -385,7 +382,7 @@ function config.loadkernel(other_kernel)
 		-- then try load with module_path=${kernel}
 		local paths = {"/boot/" .. kernel, kernel}
 
-		for k,v in pairs(paths) do
+		for _, v in pairs(paths) do
 			loader.setenv("module_path", v)
 			res = load_bootfile()
 
@@ -452,7 +449,7 @@ end
 
 function config.loadelf()
 	local kernel = config.kernel_selected or config.kernel_loaded
-	local loaded = false
+	local loaded
 
 	print("Loading kernel...")
 	loaded = config.loadkernel(kernel)

stand/lua/core.lua

@@ -200,7 +200,6 @@ function core.bootenvList()
 	local bootenv_count = tonumber(loader.getenv("bootenvs_count"))
 	local bootenvs = {}
 	local curenv
-	local curenv_idx = 0
 	local envcount = 0
 	local unique = {}
 

stand/lua/drawer.lua

@@ -38,6 +38,7 @@ local fbsd_logo
 local beastie_color
 local beastie
 local fbsd_logo_v
+local orb_color
 local orb
 local none
 local none_shifted = false
@@ -178,7 +179,7 @@ drawer.menu_name_handlers = {
 	-- This is designed so that everything, including menu separators, may
 	-- have their names derived differently. The default action for entry
 	-- types not specified here is to use entry.name directly.
-	[core.MENU_SEPARATOR] = function(drawing_menu, entry)
+	[core.MENU_SEPARATOR] = function(_, entry)
 		if entry.name ~= nil then
 			if type(entry.name) == "function" then
 				return entry.name()
@@ -187,7 +188,7 @@ drawer.menu_name_handlers = {
 		end
 		return ""
 	end,
-	[core.MENU_CAROUSEL_ENTRY] = function(drawing_menu, entry)
+	[core.MENU_CAROUSEL_ENTRY] = function(_, entry)
 		local carid = entry.carousel_id
 		local caridx = config.getCarouselIndex(carid)
 		local choices = entry.items
@@ -263,8 +264,8 @@ function drawer.drawscreen(menu_opts)
 end
 
 function drawer.drawmenu(m)
-	x = drawer.menu_position.x
-	y = drawer.menu_position.y
+	local x = drawer.menu_position.x
+	local y = drawer.menu_position.y
 
 	-- print the menu and build the alias table
 	local alias_table = {}
@@ -288,7 +289,7 @@ function drawer.drawmenu(m)
 			-- fill the alias table
 			alias_table[tostring(entry_num)] = e
 			if e.alias ~= nil then
-				for n, a in ipairs(e.alias) do
+				for _, a in ipairs(e.alias) do
 					alias_table[a] = e
 				end
 			end
@@ -303,10 +304,10 @@ end
 
 
 function drawer.drawbox()
-	x = drawer.box_pos_dim.x
-	y = drawer.box_pos_dim.y
-	w = drawer.box_pos_dim.w
-	h = drawer.box_pos_dim.h
+	local x = drawer.box_pos_dim.x
+	local y = drawer.box_pos_dim.y
+	local w = drawer.box_pos_dim.w
+	local h = drawer.box_pos_dim.h
 
 	local hl = string.char(0xCD)
 	local vl = string.char(0xBA)

stand/lua/loader.lua

@@ -27,16 +27,15 @@
 -- $FreeBSD$
 --
 
-local cli = require("cli")
+require("cli")
 local config = require("config")
 local menu = require("menu")
 local password = require("password")
-local local_module
 
-local result, errstr, errnoval = lfs.attributes("/boot/lua/local.lua")
+local result, _, _ = lfs.attributes("/boot/lua/local.lua")
 -- Effectively discard any errors; we'll just act if it succeeds.
 if result ~= nil then
-	local_module = require("local")
+	require("local")
 end
 
 config.load()

stand/lua/menu.lua

@@ -59,11 +59,11 @@ menu.handlers = {
 	-- continue or not. The return value may be omitted if this entry should
 	-- have no bearing on whether we continue or not, indicating that we
 	-- should just continue after execution.
-	[core.MENU_ENTRY] = function(current_menu, entry)
+	[core.MENU_ENTRY] = function(_, entry)
 		-- run function
 		entry.func()
 	end,
-	[core.MENU_CAROUSEL_ENTRY] = function(current_menu, entry)
+	[core.MENU_CAROUSEL_ENTRY] = function(_, entry)
 		-- carousel (rotating) functionality
 		local carid = entry.carousel_id
 		local caridx = config.getCarouselIndex(carid)
@@ -77,11 +77,11 @@ menu.handlers = {
 			entry.func(caridx, choices[caridx], choices)
 		end
 	end,
-	[core.MENU_SUBMENU] = function(current_menu, entry)
+	[core.MENU_SUBMENU] = function(_, entry)
 		-- recurse
 		return menu.run(entry.submenu)
 	end,
-	[core.MENU_RETURN] = function(current_menu, entry)
+	[core.MENU_RETURN] = function(_, entry)
 		-- allow entry to have a function/side effect
 		if entry.func ~= nil then
 			entry.func()
@@ -122,7 +122,7 @@ menu.boot_environments = {
 				    bootenv_name .. " (" .. idx .. " of " ..
 				    #all_choices .. ")"
 			end,
-			func = function(idx, choice, all_choices)
+			func = function(_, choice, _)
 				bootenvSet(choice)
 			end,
 			alias = {"a", "A"},
@@ -312,7 +312,7 @@ menu.welcome = {
 				    kernel_name .. " (" .. idx .. " of " ..
 				    #all_choices .. ")"
 			end,
-			func = function(idx, choice, all_choices)
+			func = function(_, choice, _)
 				config.selectkernel(choice)
 			end,
 			alias = {"k", "K"}
@@ -361,7 +361,7 @@ function menu.run(m)
 	if m == menu.default then
 		autoboot_key = menu.autoboot()
 	end
-	cont = true
+	local cont = true
 	while cont do
 		local key = autoboot_key or io.getchar()
 		autoboot_key = nil

stand/lua/password.lua

@@ -38,7 +38,7 @@ function password.read()
 	local n = 0
 
 	while true do
-		ch = io.getchar()
+		local ch = io.getchar()
 		if ch == core.KEY_ENTER then
 			break
 		end