Improve class prototype

local class = { }
setmetatable(class, class)

--# Standard methods

--# virtual
function class:__call(...)
	--# Call the constructor for a nice and clean syntax (class())
	return self:construct(...)
end

--# virtual
function class:construct(...)
	--# Constructs an object
	local object = { }
	setmetatable(object, self)
	self.__index = self

	local ok, err = pcall(self.init, object, ...)
	if not ok then error(err, 2) end
	return object
end

--# virtual
function class:init()
	--# Standard constructor with no special construction
end

return class

--# Constructing
local object = class()
local TestClass = class()
local InheritClass = TestClass()

--# Adding methods

function TestClass:method()
	--# Do stuff
end

--# Adding metamethods

function TestClass:__tostring()
	return "string"
end

local function magic(t, k)
    local target = t
    while true do
        local value = rawget(target, k)
        if value ~= nil then return value end
        target = rawget(target, "super")
        if target == nil then return nil end
    end
end

local function add(obj, name, parent)
    setmetatable(obj, {__index = magic)
    obj.super = parent
end

Lyqyd, on 20 October 2018 - 03:48 AM said:

local function magic(t, k)
	local target = t
	while true do
		local value = rawget(target, k)
		if value ~= nil then return value end
		target = rawget(target, "super")
		if target == nil then return nil end
	end
end
local function add(obj, name, parent)
	setmetatable(obj, {__index = magic}) --# add missing }
	obj.super = parent
end

Lyqyd, on 20 October 2018 - 03:48 AM said:

local function magic(t, k)
	local target = t
	while true do
		local value = rawget(target, k)
		if value ~= nil then return value end
		target = rawget(target, "super")
		if target == nil then return nil end
	end
end

local function add(obj, name, parent)
	setmetatable(obj, {__index = magic)
	obj.super = parent
end

Not heavily tested, but gives your objects a "super" field to trace their lineage upward, and an __index metamethod to step through that sequence.

function new(parent)
  local obj = setmetatable({}, parent)
  parent.__index = parent
  return obj
end

local obj = new(parentclass)

function parentclass:__add(a, B)/>/>/>
  return a.val, b.val
end

local inheritClass = new(parentclass)
local obj2 = new(inheritClass)
--# obj2 won't have a metamethod __add

local class = {}
class.new = function()
  local rtn = {}
  setmetatable(rtn, {__index = class})

  return rtn
end
local class2 = {}
setmetatable(class2, {__index = class})
class2.new = function()
  local rtn = {}
  local mt = {}
  for k, v in pairs(getmetatable(class)) do mt[k] = v end
  mt.__index = class2
  setmetatable(rtn,mt)

  return rtn
end

EveryOS, on 23 October 2018 - 01:02 PM said:

Copy the metamethods?

local class = {}
class.new = function()
  local rtn = {}
  setmetatable(rtn, {__index = class})

  return rtn
end
local class2 = {}
setmetatable(class2, {__index = class})
class2.new = function()
  local rtn = {}]
  local mt = {}
  for k, v in pairs(getmetatable(class)) do mt[k] = v end
  mt.__index = class2
  setmetatable(rtn,mt)

  return rtn
end

Just a guess, I don't use metatables much and I might be reading your question wrong…

superclass = class()
inheritanceClass = class(superclass)
function superclass:method()
end
local obj = inheritcanceClass:new()
function superclass:method(var)
  print("Value: ", var)
end
obj:method("hello")
-- No output, because he has the method

local class = {}
class.new = function(self)
  local rtn = {}
  setmetatable(rtn, {__index = class})
  return rtn
end
class.method = function() end
local class2 = {}
setmetatable(class2, {__index = class})
class2.new = function(self)
  local rtn = {}
  local mt = {}
  for k, v in pairs(class) do mt[k] = v end
  mt.__index = class2
  setmetatable(rtn, mt)
  return rtn
end
local superclass = class:new()
local inheritanceClass = class2:new()
local obj = inheritanceClass:new()
class.method = function(self, var)
  print("Value: ", var)
end
obj:method("hello")

EveryOS, on 23 October 2018 - 06:14 PM said:

After making some syntax error fixes and mods I get this

local class = {}
class.new = function(self)
  local rtn = {}
  setmetatable(rtn, {__index = class})
  return rtn
end
class.method = function() end
local class2 = {}
setmetatable(class2, {__index = class})
class2.new = function(self)
  local rtn = {}
  local mt = {}
  for k, v in pairs(class) do mt[k] = v end
  mt.__index = class2
  setmetatable(rtn, mt)
  return rtn
end
local superclass = class:new()
local inheritanceClass = class2:new()
local obj = inheritanceClass:new()
class.method = function(self, var)
  print("Value: ", var)
end
obj:method("hello")

On Mimic I get "Value: hello"

I will look into other metatable values

EveryOS, on 23 October 2018 - 06:46 PM said:

Here is something:

--A table called class that does class-type stuff
local class = {}
class.__index = class
class.extend = function(self, cclass)
  class2.__index = self
  setmetatable(cclass, cclass)

  return class2
end
setmetatable(class, class)

Here is a script that uses something like this:

--A table called class that does class-type stuff
local class = {}
class.__index = class
class.extend = function(self, cclass)
  cclass.__index = self
  setmetatable(cclass, cclass)
  return cclass
end
setmetatable(class, class)
local function new(val, ...)
local r = ((val.parent or class):extend(val))
r(...)
return r
end
--After class definition
local number = {
__call = function(self, number)
  self.number = number
end,
__add = function(self, val)
  if type(val) == "number" then
   return self.number + val
  else
   return self.number + val.number
  end
end
}
local wholeNumber = {
parent = number,
__call = function(self, val)
   if math.floor(val) ~= val then error("Not whole") end
   self.parent.__call(self, val)
	end,
	__add = number.__add
}
local n = new(number, 4.2)
print("TYPE OF N: "..type(n))
print(n + 5)
print(n + new(wholeNumber, 3))
print(n + new(wholeNumber, 4.2))

Note that metamethods must be manually defined