Lua子集枚举：二进制掩码的组合映射

local function pickOne(items, mask)
    local out = {}
    for k = 1, #items do
        if math.floor(mask / 2 ^ (k - 1)) % 2 == 1 then
            out[#out + 1] = items[k]
        end
    end
    return out
end

local items = {"货架A", "货架B", "货架C", "货架D"}
local total = 2 ^ #items
local p = getplayerbyname("combo01")
sendmsg(p, 1, "4 件商品共 " .. total .. " 种组合")
sendmsg(p, 1, table.concat(pickOne(items, 13), ","))