【高级技巧】原型模式：clone创建同类对象的封装

local prototype = { hp = 5000, atk = 300, ai = "patrol" }
local function clone(proto, overrides)
    local obj = {}
    for k, v in pairs(proto) do
        obj[k] = v
    end
    for k, v in pairs(overrides or {}) do
        obj[k] = v
    end
    return obj
end
local mobA = clone(prototype, { ai = "guard" })
local mobB = clone(prototype, { hp = 8000 })
print(mobA.ai, mobB.hp)

local spawns = {}
for i = 1, 5 do
    spawns[#spawns + 1] = clone(prototype,
        { ai = i % 2 == 0 and "guard" or "patrol" })
end
print(#spawns)