Add .luacheckrc and fix issues it pointed out (#589)

mesecons_microcontroller/init.lua

@@ -102,7 +102,7 @@ minetest.register_node(nodename, {
 		for i=1, EEPROM_SIZE+1 do r=r.."0" end --Generate a string with EEPROM_SIZE*"0"
 		meta:set_string("eeprom", r)
 	end,
-	on_receive_fields = function(pos, formanme, fields, sender)
+	on_receive_fields = function(pos, _, fields, sender)
 		local player_name = sender:get_player_name()
 		if minetest.is_protected(pos, player_name) and
 				not minetest.check_player_privs(player_name, {protection_bypass=true}) then
@@ -225,7 +225,6 @@ yc.parsecode = function(code, pos)
 	local Lreal = yc.get_real_portstates(pos)
 	local Lvirtual = yc.get_virtual_portstates(pos)
 	if Lvirtual == nil then return nil end
-	local c
 	local eeprom = meta:get_string("eeprom")
 	while true do
 		local command, params
@@ -251,9 +250,9 @@ yc.parsecode = function(code, pos)
 			if not params then return nil end
 		end
 		if command == "on" then
-			L = yc.command_on (params, Lvirtual)
+			Lvirtual = yc.command_on (params, Lvirtual)
 		elseif command == "off" then
-			L = yc.command_off(params, Lvirtual)
+			Lvirtual = yc.command_off(params, Lvirtual)
 		elseif command == "print" then
 			local su = yc.command_print(params, eeprom, yc.merge_portstates(Lreal, Lvirtual))
 			if su ~= true then return nil end
@@ -384,7 +383,6 @@ end
 
 --Commands
 yc.command_on = function(params, L)
-	local rules = {}
 	for i, port in ipairs(params) do
 		L = yc.set_portstate (port, true, L)
 	end
@@ -392,7 +390,6 @@ yc.command_on = function(params, L)
 end
 
 yc.command_off = function(params, L)
-	local rules = {}
 	for i, port in ipairs(params) do
 		L = yc.set_portstate (port, false, L)
 	end
@@ -405,7 +402,7 @@ yc.command_print = function(params, eeprom, L)
 		if param:sub(1,1) == '"' and param:sub(#param, #param) == '"' then
 			s = s..param:sub(2, #param-1)
 		else
-			r = yc.command_parsecondition(param, L, eeprom)
+			local r = yc.command_parsecondition(param, L, eeprom)
 			if r == "1" or r == "0" then
 				s = s..r
 			else return nil end
@@ -469,8 +466,8 @@ yc.command_after_execute = function(params)
 		if yc.parsecode(params.code, params.pos) == nil then
 			meta:set_string("infotext", "Code in after() not valid!")
 		else
-			if code ~= nil then
-				meta:set_string("infotext", "Working Microcontroller\n"..code)
+			if params.code ~= nil then
+				meta:set_string("infotext", "Working Microcontroller\n"..params.code)
 			else
 				meta:set_string("infotext", "Working Microcontroller")
 			end
@@ -543,8 +540,8 @@ yc.command_parsecondition = function(cond, L, eeprom)
 	cond = string.gsub(cond, "!0", "1")
 	cond = string.gsub(cond, "!1", "0")
 
-	local i = 2
-	local l = string.len(cond)
+	i = 2
+	l = string.len(cond)
 	while i<=l do
 		local s = cond:sub(i,i)
 		local b = tonumber(cond:sub(i-1, i-1))
@@ -553,8 +550,7 @@ yc.command_parsecondition = function(cond, L, eeprom)
 		if s == "=" then
 			if a==nil then return nil end
 			if b==nil then return nil end
-			if a == b  then buf = "1" end
-			if a ~= b then buf = "0" end
+			local buf = a == b and "1" or "0"
 			cond = string.gsub(cond, b..s..a, buf)
 			i = 1
 			l = string.len(cond)
@@ -562,8 +558,8 @@ yc.command_parsecondition = function(cond, L, eeprom)
 		i = i + 1
 	end
 
-	local i = 2
-	local l = string.len(cond)
+	i = 2
+	l = string.len(cond)
 	while i<=l do
 		local s = cond:sub(i,i)
 		local b = tonumber(cond:sub(i-1, i-1))
@@ -659,7 +655,7 @@ yc.set_portstate = function(port, state, L)
 	return L
 end
 
-yc.update_real_portstates = function(pos, node, rulename, newstate)
+yc.update_real_portstates = function(pos, _, rulename, newstate)
 	local meta = minetest.get_meta(pos)
 	if rulename == nil then
 		meta:set_int("real_portstates", 1)
@@ -696,7 +692,7 @@ end
 
 yc.get_virtual_portstates = function(pos) -- portstates according to the name
 	local name = minetest.get_node(pos).name
-	local b, a = string.find(name, ":microcontroller")
+	local _, a = string.find(name, ":microcontroller")
 	if a == nil then return nil end
 	a = a + 1