【高级技巧】状态压缩：32个开关存进一个数字

local function getBit(flags, n)
    return math.floor(flags / 2 ^ n) % 2
end
local function setBit(flags, n, v)
    local cur = getBit(flags, n)
    if cur == v then
        return flags
    end
    if v == 1 then
        return flags + 2 ^ n
    end
    return flags - 2 ^ n
end

local ACT = { SIGNUP = 0, SIEGE = 1, RANK = 2 }
local function signUp(actor, bitNo)
    local flags = tonumber(getplayvar(actor, 1, "ActFlags")) or 0
    setplayvar(actor, 1, "ActFlags", setBit(flags, bitNo, 1), 1)
    sendmsg(actor, 1, "报名成功（开关位 " .. bitNo .. "）。")
end