batteries/class.lua
2020-03-15 21:22:22 +11:00

46 lines
1.1 KiB
Lua

--[[
barebones oop basics
supports basic inheritance and means you don't have to build/set your own metatable each time
todo: collect some stats on classes/optional global class registry
]]
local function class(inherits)
local c = {}
c.__mt = {__index = c}
--handle single inheritence
if type(inherits) == "table" and inherits.__mt then
setmetatable(c, inherits.__mt)
end
--common class functions
--internal initialisation
--sets up an initialised object with a default value table
--performing a super construction if necessary and assigning the right metatable
function c:init(t, ...)
if inherits then
--super ctor, then overlay args table
t = table.overlay(inherits:new(...), t)
end
--upgrade to this class and return
return setmetatable(t, self.__mt)
end
--constructor
--generally to be overridden
function c:new()
return self:init({})
end
--get the inherited class for super calls if/as needed
--allows overrides that still refer to superclass behaviour
function c:super()
return inherits
end
--done
return c
end
return class