Lua位运算：无运算符时代的标志压缩

-- 错误：每开关一个字段，存档膨胀且难迁移
setplayvar(p, "act_1", 1)
setplayvar(p, "act_2", 0)
setplayvar(p, "act_3", 1)

local function getBit(v, i)
    return math.floor(v / 2 ^ i) % 2
end
local function setBit(v, i, on)
    local b = getBit(v, i)
    if on and b == 0 then
        return v + 2 ^ i
    elseif not on and b == 1 then
        return v - 2 ^ i
    end
    return v
end
local flags = 0
flags = setBit(flags, 3, true)
flags = setBit(flags, 0, true)
local p = getplayerbyname("bit02")
sendmsg(p, 1, getBit(flags, 3) .. "/" .. flags)