module refactoring

libs/package.lua

@@ -0,0 +1,34 @@
+if module then return end
+local _G, setfenv, setmetatable = getfenv(0), setfenv, setmetatable
+local environments, interfaces = {}, {}
+
+local function pass() end
+
+local environment_mt = {__index=_G}
+
+local function create_module(name)
+	local environment = setmetatable({_G=_G, pass=pass}, environment_mt)
+	local exports = {}
+	environment.M = setmetatable({}, {
+		__metatable=false,
+		__newindex=function(_, k, v)
+			environment[k], exports[k] = v, v
+		end,
+	})
+	environment._M = environment
+	environments[name] = environment
+	interfaces[name] = setmetatable({}, {__metatable=false, __index=exports, __newindex=pass})
+end
+
+function module(name)
+	local defined = not not environments[name]
+	if not defined then
+		create_module(name)
+	end
+	setfenv(2, environments[name])
+	return defined
+end
+
+function require(name)
+	return interfaces[name]
+end