Simple OOP for Roblox

soop.lua

--[[
Classes are simple modules placed in the SoopHierarchy folder.
Methods, functions, and properties are handled the same as in standard metatable-
based oop frameworks.
Class hierarchy follows the hierarchy of module objects in the hierarchy folder.
Single-inheritence, default constructors(:init()), etc. are handled automatically on start.
--]]


local hierarchy = script.Parent.SoopHierarchy
local soop = {}

function initClass(module, superclass)
	if soop[module.Name] then
		error("Duplicate class name in hierarchy: " .. module.Name)
	end
	
	local class = require(module)
	
	local c_mt = {__index = class, __tostring = function(obj)
		if obj.tostring then
			return obj:tostring()
		else
			return obj._classname
		end
	end}
	
	class._classname = module.Name
	class._module = module
	
	--Inherit parent class properties
	if superclass then
		setmetatable(class, {
			__index = superclass
		})
	end
	
	--Automatic object instantiation.
	--Automatically applies Class.init(obj, ...)
	--e.g. dogObj = soop.Dog.new("Porkchop")
	--     print(dogObj.name) -> Porkchop
	--(see next section for implementation of init function)
	function class.new(...)
		local obj = setmetatable({}, c_mt)
		if obj.init then obj:init(...) end
		return obj
	end
	
	
	--Java style superclass
	--e.g
	--[[
		function Dog:init(dogName)
			Dog.super().init(self, dogName) --Runs parent class initialization function
			
			--NOTE: initializing using the parent class init function is optional.
			
			self.name = dogName
		end
	--]]
	function class.super()
		return superclass
	end
	
	--Java style class checking
	--Takes a class table as argument
	--e.g. print(soop.Dog.instanceOf(soop.Animal))    -> true
	--     print(dogObj.instanceOf(soop.Dog))         -> true
	--     print(dogObj.instanceOf(soop.Animal))      -> true
	function class.instanceOf(c)
		return c == class or superclass and superclass.instanceOf(c)
	end
	
	--Roblox style class checking
	--Takes string class name as argument.
	--e.g. print(dogObj:IsA("Dog"))    -> true
	--     print(dogObj:IsA("Animal")) -> true
	function class.IsA(self, cname)
		return cname == class._classname or (superclass and superclass.IsA(self, cname))
	end
	
	soop[module.Name] = class
	
	for i, v in pairs(module:GetChildren()) do
		if v:IsA("ModuleScript") then
			initClass(v, class)
		end
	end
end

for i, v in pairs(hierarchy:GetChildren()) do
	if v:IsA("ModuleScript") then
		initClass(v)
	end
end

return soop