Planète Casio - Programmes, jeux et cours pour calculatrices Casio

local print = nbdraw.print

-- uses these function instead of () and [] to access to the metatables


-- here we can use this function if item has only one argument. There is a way to extend it to any number of argument using varargs, but I don't know how to use them.

local function my_call (item, arg)
if (item.metatable and item.metatable.call)
then item.metatable.call(item,arg)
else item(arg)
end
end

local function my_index(item, i)
if (item.metatable and item.metatable.index)
then item.metatable.index(item,arg)
else item[ i ]
end
end


class = function(prototype)
local derived = {}
local derivedMT = {
index = prototype,
call = function(proto, ...)
local instance = {}
local instanceMT = {
index = derived,
call = function()
return nil, "ERROR: Attempt to invoke an instance of a class"
end,
}
instance.metatable = instanceMT
if instance.init then
instance:init(...)
end
return instance
end,
}
derived.metatable = derivedMT
return derived
end

car = class()

function car: init(power, type, lights, etc)
self.power = power
self.type = type
self.lights = lights*2
self.options = etc
end

jeep = car(60, "4x4", 12, {airconditioning = false,trailerhook = true})
if jeep.trailerhook then
print("The jeep can have a trailer")
else
print("No trailer for you" )
end