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-- currently a class is a table T with T.__index = T
-- then to make an instance of this class, we do
-- setmetatable(instance,T)
-- this should be fine for anything we wish to do.
-- it is possible we will eventually split this into two separate
-- tables perhaps? i don't see why we would ever do that though
local function class()
local T = {}
T.__index = T
setmetatable(T, {__call = function(cls, ...) return cls.make(cls, ...) end})
return T
end
local function extend(Base)
local T = class()
for k,v in pairs(Base) do
if k:sub(1,2) == "__" and k~="__index" then
T[k]=v
end
end
getmetatable(T).__index = Base
return T
end
local function is(obj, cls)
if not type(obj) == 'table' then return false end
local mt = getmetatable(obj).__index
while mt do
if rawequal(cls, mt) then return true end
mt = (getmetatable(mt) or {}).__index
end
return false
end
return setmetatable({
class=class,
extend=extend,
is=is,
},{__call=class})
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